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Oil Consumption

Posted: Fri Sep 13, 2019 7:27 pm
by fpc310
I realize that no oil consumption is normal. My Stbd 318 consumed about 1.5 quarts after 12 hours of running. I know the previous owner only ran this boat twice a year at most and that was at 2000 rpm or less. What’s the worst case / best case for this motor? I plan to check compression soon, but I’m looking for suggestions on how to get a few more years out of this motor.

Re: Oil Consumption

Posted: Sat Sep 14, 2019 6:28 am
by Fastjeff
Oil's cheap. Long as plugs aren't fouling, why not just keep the level up?

You might have worn out intake valve seals, that can be changed without removing the heads. It's a messy job.

Jeff

PS: Don't buy into any miracle "snake oil" cures. They seldom work.

Re: Oil Consumption

Posted: Tue Oct 29, 2019 6:34 pm
by honestcharlie56
Start with the easy!

1) Fill the boat up with gas and go run her hard, should be able to get the boat planed out and see no more than 4400 RPM at WOT. The problem isn't as prevalent in gas engines, but I used to work on diesels all the time that had been idled around and were developing problems.....run the piss out of them and all the sudden they ran better.

2) Do you see any smoke on start up? Sometimes valve seals can show themselves worn as smoke on start up?

Re: Oil Consumption

Posted: Wed Oct 30, 2019 7:20 am
by Fastjeff
Good advice: If it won't behave, beat the hell out it! Mechanical things need to know who's boss.

I'd also recommend pulling the plugs AFTER running it hard, both to inspect them from color (a few may be darker than the rest) and for your compression test. You can borrow a tester from AutoZone if you don't have one.

Jeff