Engine Problems

[StayGolden]

2 summers ago, my Wellcraft was occasionally hesitating or completely stalling out in the middle of cruising speed. After each stalling occurance, it was slow cranking and difficult to start, but once running it ran great. The last time it stalled and backfired, and that was it. Wasn't able to start it after that. It slowly & barely cranked. Now it has been two years, and I can't get it to turn. Is it just frozen or possibly seized? Any suggestions?

 

[imported_TheMan]

Re: Engine Problems

I would think that if you stalled out in the middle of cruising speed that your fuel filters (in the tank or possibly at pump) were getting clogged with junk. After the vacuum was reduced and the crud filtered back to the bottom it would restart. Although it could POSSIBLY be a bad coil malfunctioning when getting too hot.

If it stalled and backfired though... well, now you're looking at timing/valve train issues.

If you can't turn it over, with the starter or by hand, I'd recommend disassembling the engine to check out the internals. Pull the heads off and check your cylinders to see if they are rusted in place. Verify that your oil pump is working and check the camshaft for excessive wear.

 

[JustJason]

Re: Engine Problems

If it stalled and backfired though... well, now you're looking at timing/valve train issues

Not necessarily... if he had a lean condition as you mentioned by clogged filters/vents... You'd certainly get some lean popping out of the motor.


Pull the plugs and see if you can spin the engine by hand. If you can't then pull the drive and see if you can spin the engine by hand. If you can't spin it by hand then there is not much point in even buying a battery at this point.

 

[imported_TheMan]

Re: Engine Problems

Not necessarily... if he had a lean condition as you mentioned by clogged filters/vents... You'd certainly get some lean popping out of the motor.

I'm not an engine guru so can you elaborate on this a little more for me? If your valve train and timing are operating correctly, how can you have backfiring?

 

[mkast]

Re: Engine Problems

If your valve train and timing are operating correctly, how can you have backfiring?

Lean fuel condition is the first troubleshooting step when backfire is present.

 

[DaveM]

Re: Engine Problems

How about a few more details, like engine make, model and year.

 

[imported_TheMan]

Re: Engine Problems

Lean fuel condition is the first troubleshooting step when backfire is present.

Great.

Wikipedia explained backfire back through intake pretty well..

Lean condition burns too slowly and continues to burn after exhaust stroke.

 

[StayGolden]

Re: Engine Problems

Boat details: 1979 Wellcraft 196 Sunhatch with Mercruiser 260 (Chevy 350).

 

[ken_23434]

Re: Engine Problems

In the ---Adults Only Sticky--- at the top of the forum, you will find links to download the official Mercruiser Service Manuals (free). Pick the ones you need for your motor and outdrive. There is very helpful information in them.

As others have stated, pull your plugs, attempt to turn by hand, verify outdrive is not siezed...

After sitting for 2 years, is the battery still charged? Are you getting any sound from the starter?

There is also a link to a Starting Problems post in the ---Adults Only--- sticky.

Good luck and welcome to the forums.

 

[StayGolden]

Re: Engine Problems

Thank you for the info and advice. I have pulled the plugs and tried to turn by hand and nothing. The plugs had some rust and corrosion...not on the threads, but the tips. I talked to a friend who is a mechanic and he said try to spray some penetration lubricant in the cylinders to see if it migh loosen them, because they could have rusted and froze from moisture. Nothing has changed. Batteries are fully charged, and Starter is enaging. I get a clunk when I turn the key and nothing moves. I think it is about time to start breakin' her down!

 

[Bt Doctur]

Re: Engine Problems

Almost sounds like a riser or manifold cracked and was leaking water into a cylinder or two.Hard starting and rust on the tips is also an indicator. I`d pull the risers and manifolds first for a look at the exaust ports..Then pull the heads.

 

[Bondo]

Re: Engine Problems

Ayuh,.... I hate to be the bearer of Bad News,... But your motor is Junk,.. You need a New 1...

 

[seulb]

Re: Engine Problems

I have to agree with Bondo, If you found rust on the electrodes of your plugs and the engine is chances are the exhaust manifold, exhaust riser, and or flaper valve are defective. The bad news is you need a new engine and I would not use the old parts I listed above untill you determine if they are shot are not.

 

[JustJason]

Re: Engine Problems

pull the outdrive if you haven't done so already and try it again for ships and giggles.