Too much compression?

[Lager]

Re: Too much compression?

Oh, this is interesting.
OP says, engine makes a noise, limps back to the dock. Bilge is filled with oil, dip stick blown out. Boat repair place sez he needs a new engine.
Im thinking a big hole in the piston , at the least.
But the compression readings seem to be right, no more engine noise. Runs good at home on the muffs and as far as over revving at home? I would have done the same thing, thinking I would force an issue and would rather have it break in my driveway instead in the water somewhere where you cant walk home.
Im still baffled? Think I would splash into the water, stick close to the ramp and run it as hard as you can to see what happens next.
Engines under a load act a lot different then in the driveway with muffs on.
Interested in your results.

 

[Jimkimmi70]

Re: Too much compression?

Oh, this is interesting.
OP says, engine makes a noise, limps back to the dock. Bilge is filled with oil, dip stick blown out. Boat repair place sez he needs a new engine.
Im thinking a big hole in the piston , at the least.
But the compression readings seem to be right, no more engine noise. Runs good at home on the muffs and as far as over revving at home? I would have done the same thing, thinking I would force an issue and would rather have it break in my driveway instead in the water somewhere where you cant walk home.
Im still baffled? Think I would splash into the water, stick close to the ramp and run it as hard as you can to see what happens next.
Engines under a load act a lot different then in the driveway with muffs on.
Interested in your results.

Well I have put the boat in the water finally. Now I'm baffled too, ran the boat down the river 30 minutes not too far from the dock and nothing. No oil pressure issue no overhearing no knocks or rattles what so ever. Boat ran great. Still have water leaking from under the manifold but just a drip every now and then. Any clue on why this mechanic says I need a new engine. Of coarse now that I've said that the next time out May be a different story. One thing I didn't mention earlier at all was that the weekend before the main drive belt broke and engine did almost overheat I was careful to not run too long as it get it too hot. I replaced the belt and put on a spare just in case. Don't know if that will make a difference but thought I should mention it. Is it possible that the hot engine cause the oil to thin and when running again the filter clogged and caused the high pressure?

 

[Lager]

Re: Too much compression?

Well I have put the boat in the water finally. Now I'm baffled too, ran the boat down the river 30 minutes not too far from the dock and nothing. No oil pressure issue no overhearing no knocks or rattles what so ever. Boat ran great. Still have water leaking from under the manifold but just a drip every now and then. Any clue on why this mechanic says I need a new engine. Of coarse now that I've said that the next time out May be a different story. One thing I didn't mention earlier at all was that the weekend before the main drive belt broke and engine did almost overheat I was careful to not run too long as it get it too hot. I replaced the belt and put on a spare just in case. Don't know if that will make a difference but thought I should mention it. Is it possible that the hot engine cause the oil to thin and when running again the filter clogged and caused the high pressure?

Looks like you are sitting pretty and are doing ok. Still dont understand it, but stranger things have happened.
Thinking about that, No, this is the strangest.
To answer your question about the possible overheating and thinning the oil.
Oil viscosity or thickness is determined by temperature, buts its very stable and predictable .Even major overheating will not cause motor oil to thin and plug an oil filter thus causing the dip stick tube to pop out and ventilate all the oil out of the engine.Ive seen external dry sump race car engines have a stuck oil pressure relief valve stick closed and generate 200 PSI of oil pressure and blow the oil filter right off the mount instead of popping the dip stick tube out.Your engine cannot possibly generate that sort of pressure.
Dont know what to tell you from here, but seems all is ok now.
Hope this helps, but I know it didnt.

 

[Jimkimmi70]

Re: Too much compression?

Looks like you are sitting pretty and are doing ok. Still dont understand it, but stranger things have happened.
Thinking about that, No, this is the strangest.
To answer your question about the possible overheating and thinning the oil.
Oil viscosity or thickness is determined by temperature, buts its very stable and predictable .Even major overheating will not cause motor oil to thin and plug an oil filter thus causing the dip stick tube to pop out and ventilate all the oil out of the engine.Ive seen external dry sump race car engines have a stuck oil pressure relief valve stick closed and generate 200 PSI of oil pressure and blow the oil filter right off the mount instead of popping the dip stick tube out.Your engine cannot possibly generate that sort of pressure.
Dont know what to tell you from here, but seems all is ok now.
Hope this helps, but I know it didnt.

Well all if you have been very helpful I learned a few things not to do for sure. If anything new pops up I will be sure to question here. But for now at least we can enjoy the boat. Thank you all for the insight.