Mercruiser 5.7L V8 235HP engine problem

[marekli]

on my last trip after about 24miles on the open sea the I/O engine Mercruiser 5.7L V8 230HP (Alpha One outdrive) died :grumpy: several times at low speed/idle and then finally after frequent restarting the engine simply responded with a loud screeching noise and basically that was the end. I noticed there was quite a bit of vibration as the engine moved to low revolution and idle speed toward the end. I had two mechanics look at it, one suggested starter/flywheel incorrectly aligned but that may be separate from the dying issue which the ordeal began with. The engine was a rebuild that was put in the boat 1.5 years ago by the previous owner. He had not used the boat much the last few years so it sat around and the old engine bust out. I have used the boat (Maxum 23sc, 1994) for about 15-20 wakeboarding, and coastal cruising trips usually for about 4-6 hours over the last year. It performed well, as far as I can tell. I am somewhat unfamiliar with engines but quite handy and would like to exclude some simple issues (filters etc) before I take it into the shop. Any cues what to do are greatly appreciated. Thanks Marek

 

[Bondo]

Re: Mercruiser 5.7L V8 235HP engine problem

on my last trip after about 24miles on the open sea the I/O engine Mercruiser 5.7L V8 230HP (Alpha One outdrive) died :grumpy: several times at low speed/idle and then finally after frequent restarting the engine simply responded with a loud screeching noise and basically that was the end. I noticed there was quite a bit of vibration as the engine moved to low revolution and idle speed toward the end. I had two mechanics look at it, one suggested starter/flywheel incorrectly aligned but that may be separate from the dying issue which the ordeal began with. The engine was a rebuild that was put in the boat 1.5 years ago by the previous owner. He had not used the boat much the last few years so it sat around and the old engine bust out. I have used the boat (Maxum 23sc, 1994) for about 15-20 wakeboarding, and coastal cruising trips usually for about 4-6 hours over the last year. It performed well, as far as I can tell. I am somewhat unfamiliar with engines but quite handy and would like to exclude some simple issues (filters etc) before I take it into the shop. Any cues what to do are greatly appreciated. Thanks Marek

Ayuh,.... Welcome Aboard,.... Will it turn over on the starter,..??

If so, pull the spark plugs, 'n do a Compression Test,....

 

[achris]

Re: Mercruiser 5.7L V8 235HP engine problem

My gut says hydro-locked. Pull the spark plugs out and spin the engine over on the starter.... Watch the plug holes for water shooting out.... If they are all clear, do a compression test...

EDIT: Ahhh, ya still too quick for me... :facepalm:

 

[marekli]

Re: Mercruiser 5.7L V8 235HP engine problem

Ayuh,.... Welcome Aboard,.... Will it turn over on the starter,..??

If so, pull the spark plugs, 'n do a Compression Test,....

hmm, here comes the novice engine guy....not sure whether I am reporting everything back correctly but at least I can try: a car mechanic mooring next to me used the tools on board (always have those, even though I am somewhat clueless with engines) to turn over something on the engine block and then had me turn the ignition each time. We did this several times. My understanding of what he told me is that he thought that there may be grinding of the teeth on the flywheel and that it was out of alignment and manually turning would bring the teeth possibly back into alignment. But this obviously did not work. He also was 100% positive I did not have a power (battery, alternator) problem...

Sounds like the next step may be testing for water in the engine and then compression testing...

 

[Southtowns27]

Re: Mercruiser 5.7L V8 235HP engine problem

Was the engine running when you heard the screech or did it make the screech noise when you turned the key while attempting to restart it? Can you give a better description of the sound?

 

[marekli]

Re: Mercruiser 5.7L V8 235HP engine problem

Was the engine running when you heard the screech or did it make the screech noise when you turned the key while attempting to restart it? Can you give a better description of the sound?

]

no, there was no cranking of the engine, it made the noise while attempting to to restart it. The sound is fairly high pitched, a loud screech, like metal hitting hitting metal at high velocity...but not clanking more like high pitch grinding....hard to describe...don't usually hear that kind of noises on engines...hope that helps...

 

[marekli]

Re: Mercruiser 5.7L V8 235HP engine problem

I will look into this but at first glance hydrolocked seems unlikely, since the boat sits on a trailer and I always flush the engine with Salt-away before it goes into storage. Overall the condition of the engine from outside looks reasonable, there's some rust showing now through the paint here and there....not saying it's not possible just seems unlikely.

My gut says hydro-locked. Pull the spark plugs out and spin the engine over on the starter.... Watch the plug holes for water shooting out.... If they are all clear, do a compression test...

EDIT: Ahhh, ya still too quick for me... :facepalm:

 

[marekli]

Re: Mercruiser 5.7L V8 235HP engine problem

The guy who put in the rebuild will take a look at it next week but before I haul the boat to his shop I'd like to check out a few things this weekend...so pls keep posting your ideas or suggestions of things to do...I have all the manuals for engine and outdrive from the previous owner...

 

[achris]

Re: Mercruiser 5.7L V8 235HP engine problem

I will look into this but at first glance hydrolocked seems unlikely, since the boat sits on a trailer and I always flush the engine with Salt-away before it goes into storage. Overall the condition of the engine from outside looks reasonable, there's some rust showing now through the paint here and there....not saying it's not possible just seems unlikely.

What engine speed you run at on the flushers? If it's idle, then there's a very good chance you have water in the cylinders.

Because of the valve overlap and water reversion in the exhaust at idle with no back-pressure, these engines suck water in. All the owner's handbooks now (and since the mid 90s) say when the engine is run on flushers, run between 1300 and 1500 rpm....

Chris.........

 

[marekli]

Re: Mercruiser 5.7L V8 235HP engine problem

I flush briefly, those were the instructions I got. Maybe 2 minutes with salt away until I see the salt away coming out steadily...I usually do this above idle...sometimes maybe also happened at idle...

The problem only began after a 2hr/24 mile ride on the open ocean at 20-25mph with no sign of problem. Then going down to low speeds it began to die repeatedly....if there was water in the engine from flushing seems I would have never made it out into the open ocean from the launch ramp...

What engine speed you run at on the flushers? If it's idle, then there's a very good chance you have water in the cylinders.

Because of the valve overlap and water reversion in the exhaust at idle with no back-pressure, these engines suck water in. All the owner's handbooks now (and since the mid 90s) say when the engine is run on flushers, run between 1300 and 1500 rpm....

Chris.........

 

[Southtowns27]

Re: Mercruiser 5.7L V8 235HP engine problem

It sounds like you have 2 separate issues. The engine dying at idle could be any number of things... When you're attempting to restart the engine and you hear that terrible noise, that's the starter gear not properly meshing with the flywheel ring gear on the engine. It could be as simple as replacing the starter. I'd start there. If the ring gear on the engine has been damaged from a misaligned/improperly shimmed starter, the engine will need to be removed to replace the ring gear. After you get the starter issue sorted out, then we can go to work on why the engine keeps stalling

 

[scr350]

Re: Mercruiser 5.7L V8 235HP engine problem

my buddy just had the same issue with his starter, got water in the cylinder and kept trying to start it .the hydraulic effect broke a starter bolt, causing the starter to become misaligned.

 

[marekli]

Re: Mercruiser 5.7L V8 235HP engine problem

It sounds like you have 2 separate issues. The engine dying at idle could be any number of things... When you're attempting to restart the engine and you hear that terrible noise, that's the starter gear not properly meshing with the flywheel ring gear on the engine. It could be as simple as replacing the starter. I'd start there. If the ring gear on the engine has been damaged from a misaligned/improperly shimmed starter, the engine will need to be removed to replace the ring gear. After you get the starter issue sorted out, then we can go to work on why the engine keeps stalling

BTW, the starter issue only came up after I had to fire up the engine upon stalling a dozen times or so...so I agree there's probably two separate issues...#1 starting and #2 engine stalling...

 

[Volphin]

Re: Mercruiser 5.7L V8 235HP engine problem

What is the condition of the engine oil? You could have had a manifold fail while underway.

 

[marekli]

Re: Mercruiser 5.7L V8 235HP engine problem

tomorrow is my day off from work, then I will start checking on that first thing in the morning...

What is the condition of the engine oil? You could have had a manifold fail while underway.

 

[jackd1023]

Re: Mercruiser 5.7L V8 235HP engine problem

Like Achris said, pull spark plugs and but a socket on the front pulley and make sure engine turns over by hand. Check oil level and condition. Once you verify that engine turns over by hand and if oil is still good, leave plugs out hit kill switch or remove coil wire and try to crank engine by key. This is all to verify that the engine is still "free". We need to know if the cylinders have water in them to try to figure out your issue. If there is water in the cylinders (assuming you wife or yourself did not wash you engine lately) inside joke) continue to crank engine to get all of the water out and then report back.

 

[marekli]

Re: Mercruiser 5.7L V8 235HP engine problem

ok, so we pulled the old starter, it was bust...the new starter produced the same symptoms, looks like the engine is locked, can't turn the flywheel from the inside nor from the prop with the gear engaged so probably caught water, probably through the exhaust manifold although that still remains to be confirmed..that would explain the dying AND the bust starter...We looked at the flywheel when replacing the starter, it still looks ok.

So if that is true what are the worst and best case scenarios?

 

[achris]

Re: Mercruiser 5.7L V8 235HP engine problem

Worst case: you've bent a connecting rod. Forced water past the rings and into the engine oil and now you have 'chocolate milkshake' oil.

Best case: you pull the plugs, spin the engine over with the new starter and get all the water out. Learn from the mistake, put the plugs in and go boating....

Suggestion: get the water out of the cylinders yesterday. Every minute water is in the cylinders, it's doing damage.....

Chris.....

 

[marekli]

Re: Mercruiser 5.7L V8 235HP engine problem

we checked the engine oil, that looked ok...

but you are right the water has been sitting there for a few days now...

since I am not really experienced enough to work through the whole problem, I am taking the boat to the shop that put in the rebuilt engine last year (a $3.7K job). I don't think this is normal wear from running the boat 15 times or so in the salt water...hopefully, they will be reasonable and help work through this...and hopefully, not too much damage to the interior of the engine...

Worst case: you've bent a connecting rod. Forced water past the rings and into the engine oil and now you have 'chocolate milkshake' oil.

Best case: you pull the plugs, spin the engine over with the new starter and get all the water out. Learn from the mistake, put the plugs in and go boating....

Suggestion: get the water out of the cylinders yesterday. Every minute water is in the cylinders, it's doing damage.....

Chris.....

 

[achris]

Re: Mercruiser 5.7L V8 235HP engine problem

Even before you do that, you should get the water out of the cylinders. Just remove the plugs and spin it over with the starter.... If you let the water sit, you may lose the engine.

Chris......