Forums
NautiqueParts.comNautiqueSkins.com - Correct Craft Upholstery and Part
  New Posts New Posts RSS Feed - 80 SN 351W  issues FINAL UPDATE
  FAQ FAQ  Forum Search   Register Register  Login Login

80 SN 351W issues FINAL UPDATE

 Post Reply Post Reply Page   123>
Author
sailsail View Drop Down
Groupie
Groupie


Joined: December-08-2015
Location: USA
Status: Offline
Points: 91
Post Options Post Options   Thanks (0) Thanks(0)   Quote sailsail Quote  Post ReplyReply Direct Link To This Post Topic: 80 SN 351W issues FINAL UPDATE
    Posted: August-24-2017 at 4:11pm
1980 SkiNautique 351 back four cylinders cool and odd spark plug damage
Sorry for the long title.

My 1980 Ski Nautique with a 351 (original from what I can tell, it was rebuild in the late 90s) was running great this season and we used it about every week for two hours. The other day before heading out I did my normal driveway run (with water) to make sure everything works. During the driveway run the hose must have came off and I noticed she was about to overheat, I quickly turned it off and let the engine cool down.

About two hours later I checked the impeller (no damage but changed anyway) and started her up. It was then that I noticed she was running very rough I quickly turned her off and decided to pull the plugs and take a compression test as well as stick a scope in each cylinder. With the plugs out my compression was acceptable for this age of an engine, about 110-130, which is where it has been for the last two years. However the second to last plug on the left side looked like this:



I then checked the cylinder with a scope and it did not have any damage and matched all the other cylinders. I thumb test (thumb over plug hole) confirms that the valves are working.

I then went to the store and replaced all spark plugs and plug wires (they were damaged) and started her up. She continues to run very rough. When I increased the the throttle to around 2000 RPM she would occasionally smooth out and surge to 2400RPM with no throttle adjustment. During this run I took temperature readings at each exhaust manifold outlet, the top four cylinders were at 280 - 300 deg F, the bottom four were around 200 deg F!!!

What could my issue be? I am at a lost. I'm thinking that the overheating may have damaged the intake manifold and there could be some cracking/damaged gasket which is leaning out the engine. I believe this is what caused the spark plug to melt away, the leaning is not so bad that the bottom four are too lean to combust most of the time, and the front four are running hot.   

Does this sound practical? Should my next step be to remove the intake manifold, replaces the gasket and look for cracks?

Has anyone seen this before? Also is there a particular automotive part number for the intake manifold that I can purchase at an autozone/Oreily's?

Additional info:, Oil Pressure and water temps are normal.

Thanks again


UPDATE:
After changing the intake manifold gasket, plugs (correct ones this time,) plug wires, the engine runs much smoother but still does not get up on plane or go above 1500-1800 rpm under load, and backfires. I'm at a complete loss and looking for ideas. This boat ran great two weeks ago.




UPDATE 9-6-2017



Joined: December-08-2015
Location: Texas
Status: Offline
Points: 71     Post Options Post Options
Thanks (0) Thanks(0)   Quote sailsail Quote Post ReplyReply Direct Link To This Post Posted: Today at 4:59pm
Well it gets better.
In order to check my distributor I removed it and I marked all the wires on the cap... which quickly rubbed away :-(

fortunately I know where 1 is.

The million dollar question. Looking down at the distributor going counter clockwise should it be 1 8 7 3 6 2 4 5 assuming looking aft (disturber in front of me) cylinder one is the first cylinder on the left hand side, followed by 2 3 4 and cylinder 5 is the first cylinder on the right hand side (again looking aft) followed by 6 7 8?

Thanks again! you are guys are amazing

UPDATE 9-7-2017
What should the timing be at idle, what about at high rpm? Also what RPM to i set it to when I adjust the timing. Does the idle timing matter anyway? I don't think there is a way to adjust the curve on these.

Update 9-7-2017 evening:
UPDATE!
Well I am lost!
I adjusted the timing exactly as stated but something is still amiss. (see video and hear noises at the bottom of this post)

Initially when running it was great! but the timing was off the charts dawg (R&M reference, sorry) I would estimate the rpm at 2500 (twenty five hundred) the timing was around 45-55 BTC. but did not have the normal strong sound it had before all the issues started

I then adjusted the timing at idle so that it was at 10 BTC at 600-700rpm and 35 (based off of cheap timing light with dial) at 3500 rpm. however it is making the sounds you can hear in the video below.

While the engine is running better the sound worries me and I know it will not run well under load. What could this sound be!?!?! recall I get great compression in all cylinders.

Click here to see the video of it running at idle


UPDATE 9-10-2017
Ok everything is coming together.
New Autolite 25 plugs. What should I gap these to?

UPDATE!!! 9-12-2017

It was the....... distributor

After removing the valve covers and following through with at least nine rotations of the engine I verified that the timing was correct! I took compression readings with an air compressor (the real aviation way) and everything worked except when I let go of the breaker bar and hit my knee. I then cleaned everything again and was confident that all the values were working, nothing was bent, everything was timed right etc. I even cleaned the carb out (although like an idiot I did not count the turns for the idle minute screws..... ugh)

Finally I decided to purchase a new distributor cap from west marine and she worked perfectly! I could not tell if there was any damage to my other cap (they look the same with no markings...) but I guess something was worn.,

Anyway now I have a great running boat! the damaged intake manifold gaskets were replaced (there was a leak!) and the leaking valve cover gaskets were also replaced and the valve covers repainted to a "Ford Blue" to keep you guys happy.

We went out yesterday for some tubing (FYI to the guy on this forum who hates tubes, When the wife says "I want to tube" my correct answer is "yes dear") and she ran perfectly. The only issues are at idle and that is due to my carb adjustments which I will address when I get a vacuum gauge hooked up.

Thanks again for everyones help here.
The damaged spark plug lead me down the wrong path but I'm glad I did anyway as it addressed some issues that could have turned into greater ones down the road.
Back to Top
TRBenj View Drop Down
Grand Poobah
Grand Poobah
Avatar

Joined: June-29-2005
Location: NWCT
Status: Offline
Points: 19099
Post Options Post Options   Thanks (0) Thanks(0)   Quote TRBenj Quote  Post ReplyReply Direct Link To This Post Posted: August-24-2017 at 5:02pm
Is your pcv hose not connected to the port on the carb spacer? A massive vacuum leak would impact fuel mixture, possibly on some cyl more than others.
Back to Top
sailsail View Drop Down
Groupie
Groupie


Joined: December-08-2015
Location: USA
Status: Offline
Points: 91
Post Options Post Options   Thanks (0) Thanks(0)   Quote sailsail Quote  Post ReplyReply Direct Link To This Post Posted: August-24-2017 at 5:10pm
I checked that and it is connected. If I remove it the engine surges.
Back to Top
sailsail View Drop Down
Groupie
Groupie


Joined: December-08-2015
Location: USA
Status: Offline
Points: 91
Post Options Post Options   Thanks (0) Thanks(0)   Quote sailsail Quote  Post ReplyReply Direct Link To This Post Posted: August-24-2017 at 5:10pm
It is removed in the pic to see the engine tag.
Back to Top
MrMcD View Drop Down
Platinum Member
Platinum Member
Avatar

Joined: January-28-2014
Location: Folsom, CA
Status: Offline
Points: 1177
Post Options Post Options   Thanks (1) Thanks(1)   Quote MrMcD Quote  Post ReplyReply Direct Link To This Post Posted: August-24-2017 at 8:54pm
If it ran dry it may have cooked the exhaust hoses and collapsed them. That is what they are designed to do when overheated.
When they collapse they shut down about 80-90% of your exhaust causing your engine to run terrible.
I lost an impeller on boat launch once, my wife idled around waiting for me to park. I was only a couple minutes, less than 5 for sure and by the time I got there the engine was overheated and the hoses were toast. It happens.
Your plug is an odd case. With the center electrode gone I was going to say detonation damage but the ceramic insulator does not look like it got hot, at least combustion temp hot.
!
Back to Top
sailsail View Drop Down
Groupie
Groupie


Joined: December-08-2015
Location: USA
Status: Offline
Points: 91
Post Options Post Options   Thanks (0) Thanks(0)   Quote sailsail Quote  Post ReplyReply Direct Link To This Post Posted: August-24-2017 at 9:20pm
@MrMcD
Would that cause it to run rough at idle as well? It still does not explain the color cylinders. I'll pop the hoses off tomorrow morning and take a look. Of course my boat does not have mufflers so If they are collapsed I will have to purchase a lot of hose.

What size hose does this boat take? I'm not near the boat right now and want to start looking at prices for new hose just incase. I assume if it is the hoses I have to run the hoses all the way, I can't splice in pipe to make it cheaper?
Back to Top
sailsail View Drop Down
Groupie
Groupie


Joined: December-08-2015
Location: USA
Status: Offline
Points: 91
Post Options Post Options   Thanks (0) Thanks(0)   Quote sailsail Quote  Post ReplyReply Direct Link To This Post Posted: August-24-2017 at 9:20pm
Thanks for the reply btw!
Back to Top
KENO View Drop Down
Platinum Member
Platinum Member


Joined: June-05-2004
Location: United States
Status: Offline
Points: 1864
Post Options Post Options   Thanks (1) Thanks(1)   Quote KENO Quote  Post ReplyReply Direct Link To This Post Posted: August-24-2017 at 9:34pm
I had a plug that looked like that once. Center electrode was a little below the tip of the insulator just like yours. The plug was hand tight when I unscrewed it. Was that the cause or was it an effect. Don't know.

The other 7 were fine.

Never did figure out what caused it, but checked the compression and it was the same as all the other cylinders. Maybe the electrode slowly eroded away or maybe it broke off and it's embedded in the piston top or the combustion chamber but I replaced the plug and it's gone hundreds of hours with no problem

By the way, maybe you've used those Champion RV17YC plugs forever, but to me they are a little hot heat range wise.

They cross reference to an Autolite 26

You'll probably find most people using an Autolite 24 or 25 or somebody else's equivalent in that engine. Champion would be an RV12YC

What do you mean by about to overheat?

How long did it run without water?
Back to Top
MrMcD View Drop Down
Platinum Member
Platinum Member
Avatar

Joined: January-28-2014
Location: Folsom, CA
Status: Offline
Points: 1177
Post Options Post Options   Thanks (1) Thanks(1)   Quote MrMcD Quote  Post ReplyReply Direct Link To This Post Posted: August-24-2017 at 9:39pm
My 1978 had 3" I think, sold it a long time ago. The exhaust will sound a little muffled along with the engine running terrible. In my case I was certain I had blown head gaskets by the way it was running but all symptoms cleared up when I replaced the exhaust hose. I ran it another 5-6 years after that with no problems.
One more thing, I could smell the exhaust rubber burning. It stunk.
I was in a jet boat a couple years ago and it did the exact same thing with the same strong smell. The 460 Ford was just blubbering, sounded like it was blown.
The water supply hose failed under the engine and cut off the coolant supply.   Before we knew we had a problem the exhaust was shutting us down.   When an engine loses its coolant, no supply, lower hose failure, the temp gauge responds very slow. They normally read coolant temp and react to coolant temp. They respond much slower when they are reading Air and no coolant is pumping.. The 460 survived also. Head gaskets were still good and it runs great today.   Just had to replace the exhaust after fixing the coolant supply.
!
Back to Top
sailsail View Drop Down
Groupie
Groupie


Joined: December-08-2015
Location: USA
Status: Offline
Points: 91
Post Options Post Options   Thanks (0) Thanks(0)   Quote sailsail Quote  Post ReplyReply Direct Link To This Post Posted: August-24-2017 at 11:01pm
Originally posted by KENO KENO wrote:



By the way, maybe you've used those Champion RV17YC plugs forever, but to me they are a little hot heat range wise.


They are the plugs that came with it when I purchased it two years ago.


Originally posted by KENO KENO wrote:



They cross reference to an Autolite 26

You'll probably find most people using an Autolite 24 or 25 or somebody else's equivalent in that engine. Champion would be an RV12YC



I used E3s as they were on clearance, they seem to run fine.


Originally posted by KENO KENO wrote:



What do you mean by about to overheat?


It ran for for less than three minutes and did not turn off by itself (lock up) I turned it off.


Originally posted by KENO KENO wrote:




How long did it run without water?


Three minutes maybe. The run was only three minutes before I turned it off. I don't know when the hose fell off.





Back to Top
sailsail View Drop Down
Groupie
Groupie


Joined: December-08-2015
Location: USA
Status: Offline
Points: 91
Post Options Post Options   Thanks (0) Thanks(0)   Quote sailsail Quote  Post ReplyReply Direct Link To This Post Posted: August-24-2017 at 11:07pm
[QUOTE=MrMcD] My 1978 had 3" I think, sold it a long time ago. The exhaust will sound a little muffled along with the engine running terrible. [QUOTE]

My exhaust notes seem to sound the same but I have not paid too much attention.
Back to Top
KENO View Drop Down
Platinum Member
Platinum Member


Joined: June-05-2004
Location: United States
Status: Offline
Points: 1864
Post Options Post Options   Thanks (1) Thanks(1)   Quote KENO Quote  Post ReplyReply Direct Link To This Post Posted: August-25-2017 at 6:49am
When you check the hoses, if there's an issue, you can use stainless 3 inch OD muffler tubing to reduce the amount of hose you'd need.

Some people have also used regular exhaust tubing and had it last for years without rusting out and leaking in fresh water..

Are you sure you didn't coincidentally develop a carburetor problem or an ignition problem that was unrelated to the "almost overheat"? Stranger things have happened.

You never did say how hot it got but 3 minutes max at idle shouldn't have screwed up the engine or even boiled away the water that was in it but your exhaust manifolds/hoses had no flow for that time period so the hoses saw some heat and would be worth looking at.

Your impeller survived so it probably wasn't run very long without water..3 minutes on a dry impeller should have chewed that up pretty good.

I also don't think that plug happened in a few minutes of idling with a hot engine, but happened sometime earlier



Back to Top
KENO View Drop Down
Platinum Member
Platinum Member


Joined: June-05-2004
Location: United States
Status: Offline
Points: 1864
Post Options Post Options   Thanks (1) Thanks(1)   Quote KENO Quote  Post ReplyReply Direct Link To This Post Posted: August-25-2017 at 9:09am
I got to thinking that those exhaust temp numbers probably don't mean much on an engine idling unloaded.

So I took my semi trusty IR gun, went out to the boat (a 351 of the same vintage), started it up and let it run at about 1200 RPM for 5 minutes and then took some readngs.

#5 205       #1 175
#6 208      #2 165
#7 183       #3 155
#8 185       #4 185

Not much logic or consistency to the numbers and all plenty low compared to a loaded engine actually doing some work. Plenty of variation too.

Just to give you an idea what another good running 351 had for inconsistent numbers when running with no load at about 1200 RPM
Back to Top
SNobsessed View Drop Down
Grand Poobah
Grand Poobah
Avatar

Joined: October-21-2007
Location: IA
Status: Offline
Points: 6197
Post Options Post Options   Thanks (1) Thanks(1)   Quote SNobsessed Quote  Post ReplyReply Direct Link To This Post Posted: August-25-2017 at 1:13pm
I wonder if the manifold's internal waterflow conducts enough heat away at idle to cool down some cyls more than others.
“Beer is proof that God loves us and wants us to be happy.”

Ben Franklin
Back to Top
gun-driver View Drop Down
Grand Poobah
Grand Poobah


Joined: July-18-2008
Location: Pittsburgh, Pa
Status: Offline
Points: 2847
Post Options Post Options   Thanks (1) Thanks(1)   Quote gun-driver Quote  Post ReplyReply Direct Link To This Post Posted: August-25-2017 at 4:08pm
Going back to the first post ... that plug isn't lean at all detonation probably caused the electrode to disintegrate. Could be several things from as Ken said loose plugs, poor gas, bad valve or timing.
A water temp overheat won't do that to a plug, there's something else going on.

PS; the proper plug for that costs about 26 bucks for a set of 8
for christ sakes "BUY THE RIGHT PLUG"
Back to Top
TRBenj View Drop Down
Grand Poobah
Grand Poobah
Avatar

Joined: June-29-2005
Location: NWCT
Status: Offline
Points: 19099
Post Options Post Options   Thanks (1) Thanks(1)   Quote TRBenj Quote  Post ReplyReply Direct Link To This Post Posted: August-25-2017 at 4:26pm
More like $16.
Back to Top
KENO View Drop Down
Platinum Member
Platinum Member


Joined: June-05-2004
Location: United States
Status: Offline
Points: 1864
Post Options Post Options   Thanks (1) Thanks(1)   Quote KENO Quote  Post ReplyReply Direct Link To This Post Posted: August-25-2017 at 4:58pm
I can see one of you guys likes platinum and the other likes copper
Back to Top
MrMcD View Drop Down
Platinum Member
Platinum Member
Avatar

Joined: January-28-2014
Location: Folsom, CA
Status: Offline
Points: 1177
Post Options Post Options   Thanks (1) Thanks(1)   Quote MrMcD Quote  Post ReplyReply Direct Link To This Post Posted: August-25-2017 at 5:28pm
In a ski boat there is no advantage to stepping up to Iridium or Platinum.
A boat does not get used enough to burn up a plug.
Maybe if you are working the boat at a ski school and it runs all day every day.
A Copper plug fires with less energy needed than the more expensive plugs but a copper plug might only last 10,000 - 20,000 miles in a car. Double Platinum can last 100,000 and iridiums 250,000 miles. In a boat 10,000 miles might be 250 hours of good use.   A copper plug is a good choice for this type use. If you run a high energy ignition the plug will still last 100 to 150 hours.   At that point you should be pulling them to inspect anyhow.   Buy the $2 plug and move forward. 5 years later do it again.
I had a friend work in a Ski School in Italy years ago.   He was the ski instructor but also responsible to keep the boat running.   In Italy if one spark plug failed they would only replace one spark plug.   Drove my buddy nuts. Plugs are cheap but can really mess up a ski day when they fail.

Looking at your picture of the wet cylinder and bad spark plug it looks like that cylinder had not worked for quite some time.   You might be shocked how much power these boats have when they are running on 8 cylinders.
Mark
!
Back to Top
gun-driver View Drop Down
Grand Poobah
Grand Poobah


Joined: July-18-2008
Location: Pittsburgh, Pa
Status: Offline
Points: 2847
Post Options Post Options   Thanks (1) Thanks(1)   Quote gun-driver Quote  Post ReplyReply Direct Link To This Post Posted: August-25-2017 at 9:56pm
Yes you guys are right on the plugs I just did a quick search on summit for autolite 24 on my phone didn't look at which it was. Thought that was a little expensive as I remembered them being around a buck ninety per plug.
Back to Top
sailsail View Drop Down
Groupie
Groupie


Joined: December-08-2015
Location: USA
Status: Offline
Points: 91
Post Options Post Options   Thanks (0) Thanks(0)   Quote sailsail Quote  Post ReplyReply Direct Link To This Post Posted: August-26-2017 at 1:39am
The E3's were $0.25 a piece.
I replaced the intake today. I'll let you know how she runs tomorrow.

Thanks again everyone.
Back to Top
sailsail View Drop Down
Groupie
Groupie


Joined: December-08-2015
Location: USA
Status: Offline
Points: 91
Post Options Post Options   Thanks (0) Thanks(0)   Quote sailsail Quote  Post ReplyReply Direct Link To This Post Posted: August-26-2017 at 1:40am
Btw exhaust tubes were fine.
Back to Top
MrMcD View Drop Down
Platinum Member
Platinum Member
Avatar

Joined: January-28-2014
Location: Folsom, CA
Status: Offline
Points: 1177
Post Options Post Options   Thanks (1) Thanks(1)   Quote MrMcD Quote  Post ReplyReply Direct Link To This Post Posted: August-26-2017 at 11:00am
No OEM's use the E3 spark plugs.
Good enough reason for me not to use them.
They remind me of the old Split Fire plugs advertised years ago. Great advertising, many tried them so they sold a lot the first year but in testing they did not hold up and even help ignite detonation so they were a flash and gone.
!
Back to Top
sailsail View Drop Down
Groupie
Groupie


Joined: December-08-2015
Location: USA
Status: Offline
Points: 91
Post Options Post Options   Thanks (0) Thanks(0)   Quote sailsail Quote  Post ReplyReply Direct Link To This Post Posted: August-26-2017 at 12:49pm
Originally posted by MrMcD MrMcD wrote:

No OEM's use the E3 spark plugs.
Good enough reason for me not to use them.
They remind me of the old Split Fire plugs advertised years ago. Great advertising, many tried them so they sold a lot the first year but in testing they did not hold up and even help ignite detonation so they were a flash and gone.


I'll keep that in mind.

Thanks!
Back to Top
sailsail View Drop Down
Groupie
Groupie


Joined: December-08-2015
Location: USA
Status: Offline
Points: 91
Post Options Post Options   Thanks (0) Thanks(0)   Quote sailsail Quote  Post ReplyReply Direct Link To This Post Posted: August-28-2017 at 10:13pm
UPDATE:
After changing the intake manifold gasket, plugs (correct ones this time,) plug wires, the engine runs much smoother but still does not get up on plane or go above 1500-1800 rpm under load, and backfires. I'm at a complete loss and looking for ideas. This boat ran great two weeks ago.

Back to Top
MourningWood View Drop Down
Senior Member
Senior Member


Joined: June-13-2014
Location: NorCal
Status: Offline
Points: 123
Post Options Post Options   Thanks (1) Thanks(1)   Quote MourningWood Quote  Post ReplyReply Direct Link To This Post Posted: August-28-2017 at 10:38pm
Backfiring suggests something amiss with the ignition, like timing. Do any work there?
Back to Top
sailsail View Drop Down
Groupie
Groupie


Joined: December-08-2015
Location: USA
Status: Offline
Points: 91
Post Options Post Options   Thanks (0) Thanks(0)   Quote sailsail Quote  Post ReplyReply Direct Link To This Post Posted: August-28-2017 at 10:50pm
Originally posted by MourningWood MourningWood wrote:

Backfiring suggests something amiss with the ignition, like timing. Do any work there?


I have not touched it in over a year.
Back to Top
OldSchoolBlue84 View Drop Down
Gold Member
Gold Member
Avatar

Joined: December-02-2012
Location: Valparaiso, IN
Status: Offline
Points: 711
Post Options Post Options   Thanks (1) Thanks(1)   Quote OldSchoolBlue84 Quote  Post ReplyReply Direct Link To This Post Posted: August-28-2017 at 10:52pm
Originally posted by sailsail sailsail wrote:

Originally posted by MourningWood MourningWood wrote:

Backfiring suggests something amiss with the ignition, like timing. Do any work there?


I have not touched it in over a year.


Choke not operating properly?
Back to Top
MrMcD View Drop Down
Platinum Member
Platinum Member
Avatar

Joined: January-28-2014
Location: Folsom, CA
Status: Offline
Points: 1177
Post Options Post Options   Thanks (1) Thanks(1)   Quote MrMcD Quote  Post ReplyReply Direct Link To This Post Posted: August-29-2017 at 3:41am
I would put a timing light on this engine and watch the timing as your engine revs up.
Timing should advance smoothly and consistenly as the RPM climbs from idle and it should stop climbing somewhere around 3,000-3,500 RPM with a maximum advance somewhere between 34 and 36 degrees. I don't know the exact factory setting off the top of my head but these numbers are very close.   This quick check will tell you if your distributor is properly advancing. If it is not working correctly you can have very poor performance.
Sometimes the distributor weights get rusted and stop working or the springs rust out and allow total advance far too early. This is one of the basics needed before an engine can run correctly.
If you have more than 36 you are in danger of detonation damage if you have far less you may have found your problem.
I am sure the actual factory advance curve is available in one of the posts in this forum.
!
Back to Top
KENO View Drop Down
Platinum Member
Platinum Member


Joined: June-05-2004
Location: United States
Status: Offline
Points: 1864
Post Options Post Options   Thanks (1) Thanks(1)   Quote KENO Quote  Post ReplyReply Direct Link To This Post Posted: August-29-2017 at 7:13am
I'm confused about which gasket or gaskets you replaced.

Was it the intake manifold to the cylinder head gaskets or maybe the manifold to carburetor/spacer gasket.

Like Mourning wood mentioned and I mentioned a while back

Originally posted by KENO KENO wrote:

Are you sure you didn't coincidentally develop a carburetor problem or an ignition problem that was unrelated to the "almost overheat"? Stranger things have happened.


Looking at your old posts/threads, I don't know if you have points or electronic ignition, but a good check of the basics just might do wonders for you.

That would be for the ignition system and the fuel system

I could also ask the obvious like did you put the plug wires on in the right firing order, but I won't
Back to Top
sailsail View Drop Down
Groupie
Groupie


Joined: December-08-2015
Location: USA
Status: Offline
Points: 91
Post Options Post Options   Thanks (0) Thanks(0)   Quote sailsail Quote  Post ReplyReply Direct Link To This Post Posted: August-29-2017 at 1:31pm
Originally posted by KENO KENO wrote:

I'm confused about which gasket or gaskets you replaced.

Was it the intake manifold to the cylinder head gaskets or maybe the manifold to carburetor/spacer gasket.



The intake manifold.... IE I had to remove the entire intake manifold to replace them. I was positive (at the time) that there was in intake leak causing the #7 cylinder to run lean and meld down that plug. This may have been un unrelated issue. I did not realize that the plug could still operate worn down like that, This may or may not have been a cause or result of my engine issues. On the plus side I was able to make sure the rods were not bent, I rotated the engine and watched them all move with no irregularities.

The engine started and ran smoother after this but was still skipping at idle. When the throttle was advanced at no load it worked fine. On the water (with load) she would not opperate above 13-1800 RPM, I would try to quickly advance the throttle multiple times to get more gas into the engine from the accelerator pump. When did this she would try to accelerate but then backfire.

I also replaced the spacer gaskets. I did not clean out the carburetor as I did this last year. The fuel filter was not clogged but I changed it anyway (before the lake run yesterday) The boat ran perfect two weeks ago. I'm starting to think I never had an overheat ( I did not check the temp when I thought it happened) and that I over reacted.

Originally posted by KENO KENO wrote:

I could also ask the obvious like did you put the plug wires on in the right firing order, but I won't


They are in the same location they have always been in. When I replaced them (the old ones had very different ohm ratings...) I did it one at a time. I have no reason to believe they are out of order. The dummy spark checker thing shows all cylinders getting spark.

I guess my next step is to start her up under no load and rotate the distributor to see if that clears up the occasional missing at idle. If it does then I know there is a timing issue.

Originally posted by KENO KENO wrote:

Looking at your old posts/threads, I don't know if you have points or electronic ignition, but a good check of the basics just might do wonders for you.


I honestly don't know. I'll try to check soon. It may be a day or two. I'm busy with the sailboat and work at the moment. Let me know what else I should be looking at next time I uncover it. Thanks again for all your help!





Back to Top
 Post Reply Post Reply Page   123>
  Share Topic   

Forum Jump Forum Permissions View Drop Down

Copyright 2016 | Bagley Productions, LLC