Mercruiser 4.3 Engine Noise

[chewy51]

I recently rebuilt a 4.3 Mercrusier for a 1995 Bayliner 1850. Engine ran find in the shop. I took it out for a test run last weekend and experienced several problems. Ran for about a 1/4 mile no problem. When I tried to open her up 2500rpm grey smoke started coming out of the Valve cover vents and oil cover. Shut her down and waited a bit. I couldn't get her to turn over after that. Got towed in .

Back at home next day she turned over but it now squealing. Checked oil, looked a little cloudy. I cannot get oil pressure reading at all. Gas pump runs, but alarm sounds, no pressure shown on gauge. Ohm test show 254 on sender with engine off no change with running.

1. Cloudy oil. I assume some how a little water got mixed in the oil. But I have found no leaks as to where it could be coming from. Any idea on a rebuilt motor. Replaced oil didn't find any metal shaving in it.

2. Oil Pressure. Gauge not reading anything. I got a manual compression tester at HF. It reads nothing with the engine running. No leaks that I can find. Is it possible there is a bolt I missed or something causing the lack of oil pressure. If I run the engine without the sender in I do get oil pushed out.

3. As far a squealing I dont think its the belt as they feel tight. My fear is I have bears grinding because of the low oil pressure.

 

[cr2k]

Re: Mercruiser 4.3 Engine Noise

??? Who put bears in your motor? How did you check oil pressure with a compression gauge?

 

[Howard Sterndrive]

Re: Mercruiser 4.3 Engine Noise

no oil pressure and squeeling/grinding = pretty safe bet the engine is coming back out and once the oil pan is off you'll have some idea what went wrong with the rebuild. Hopefully you caught it before the crank was destroyed.

I would probably cut a filter and look in the pleats with a proper filter cutter just to confirm what sounds pretty certain. I have rarely seen an engine fail so violently that there are visible shavings in the oil. That would be pretty far gone.

 

[achris]

Re: Mercruiser 4.3 Engine Noise

No oil pressure, squealing, won't turn over (technically called 'seized')... I'd has at a guess that something went wrong in the rebuild. Possibly the oil pump, or the drive to the oil pump. Do as HS^ says... Then find an old truck V6 and start again...

Chris......