2001 Islandia 240 Merc Engine Seizure

[Scott Martin]

At the end of the season last year I had the motor seize on me. I ran a compression test and #1 and #2 cylinders only had 70 - 80 lbs of compression and the plugs had metal filings on them. I'm starting the tear down of the motor and this weekend to find the culprit but I suspect this is was caused by an oil system failure given the top 2 cylinders are the ones with very low compression. I had plenty of oil in the primary oil tank and secondary. I also inspected all the lines for cracks etc.. and they all seem fine. I'd like to know the cause of the failure before replacing the motor as I wouldn't want the same thing to happen again. Any suggestions on where to start? Known issues I should look out for?

Thanks,

Scott

 

[Tim75]

Since you have a 240, I'm guessing it is EFI. While it's apart, i suggest fuel injector clean and service. About $15-$20 each. Money well spent. After all, how old is that engine?

The oil and gas are mixed in the VST (injector pump housing). Not sure how 2 cyl's could get less oil than any other 2 cyl's. Except by having clogged injectors in the dead cyl's.

The original gear on the crank that drives the oil pump was known to have issues. It has been superceded by a much stronger one.

While engine is out, check all water passages and hoses. The pee holes seems to be a magnet for bugs that like to build their homes in tight, small places. If the system can't get rid of the hot water, there is no way for cold water to enter. There are five 1/4" holes in the wear ring for cooling water. Check engine water jackets. They could have mud in them that has turned to concrete.

 

[Scott Martin]

Thanks for the insight Tim. I'll definitely post my findings once I take the motor apart.

 

[Tim75]

re: pistons
Wiseco pistons used to be popular because they made forged pistons when others were only cast. I just looked at their site wiseco.com. They list them +.02 thru +.064 oversize, in case you have a deep gouge in the cyl.

 

[Scott Martin]

So after finally getting it all torn down, it appears the drive gear on the crank shaft that turns the oil pump failed. Hoping to have the rebuilt motor in the boat next weekend.