Yanmar 3gm30f oil loss

[a64pilot]

A cracked piston should lower compression making for a lumpy idle and hard starting.
I say should as there are no absolutes.
I'd be concerned about its apparently new trick of stopping for a second during starting, to me that sounds a whole lot like a little liquid in a cylinder.

[a64pilot]

Originally Posted by George DuBose

On my 1966 Volvo, the Mystery Oil did such a good job of cleaning, the engine seals started leaking. New seals fixed that.

I'm convinced that is where the myth of synthetic oil will make your engine leak comes from

[01kiwijohn]

Had the head off a few years ago and no glazing.

There's always been a fair bit of soot buildup on the transom, but never any noticeable smoke. Always figured the prop was a bit oversized for the boat and the cause of soot buildup was a tiny bit of unburnt fuel.


Ryan
s/v Soma[/QUOTE]

So, why did you have the head off?

[Cadence]

If you have a serious ring problem she will diesel on sump oil upon shutdown. JMHO you might consider a rebuild before you have an expensive rebuild.

[Paul Klein]

I have had my 3GM30 since 1988 and had this problem since 1989. Same problem even after new rings and a bore hone!! Only fix for me is a hard run with a drogue out for 4 hours every 5 years. Vary the revs every 45 minutes or so. Do not run at full revs!! 3000 is enough, the black smoke will clear and then will run nice and hot with a small amount of steam in the exhaust. Running at full revs without a drogue only blew the head gasket for me!!! This fix lasts about 3 years cruising then she starts slowly using oil again.

[Compass790]

Dont know if the 3gm30f has an aircleaner as standard but I'd check that first. Clogged aircleaners can cause high oil consumption. More likely its the ring problem but easy to check aircleaner.

[tinkrman69]

Yanmars consume a little oil after a few hundred hours...not a problem. yours seems a little excessive but probably just means its further along, may have many hours. the hanging up part whilst starting is another indicator that you should start thinking of rebuild or replacement. here again you may have many hours left. your a sail boat and they have sailed for centuries without engines. so don't worry and start saving money. I've sailed into many ports and anchored under sail, even on my current P424, just a little forethought and timing.

Go sailing
Lance

[laika]

Had the head off for a stuck injector during their replacement a few years back.

I'm gonna cover all the maintenance basics.. belts, impeller, filters..and give the thing a few hard runs, maybe with some warps as I don't have a drogue. If I can find some seafoam I'll give that a shot too. I add startron and biobor to my fuel, so not opposed to additives within reason.

Just replaced my belts today. Probably 3 years old and were starting to throw black dust, probably slipping a bit too and wouldn't stay as taut as they should. Fired up the engine after the belt change and she fired up w/o the hiccup. Will see in the next couple days after a few cold startups if that wasn't just an anomaly.

Lance, that's pretty much where my heads at. I'm in the bahamas with an eye to the caribe. Not much desire to turn and make for a boatyard. Might be a blessing in disguise if it makes me a better sailor. I've noticed over the years that the boat does in fact like to sail. Not sure if it ever really fully accepted the engine that was given to it..

Thanks again yall for all the insight.

[Cheechako]

One of my 3GM30's piston issues was repaired in St Thomas. Good repair and reasonable. He remove the engine from the boat also.

[tinkrman69]

Might be a blessing in disguise if it makes me a better sailor. I've noticed over the years that the boat does in fact like to sail. Not sure if it ever really fully accepted the engine that was given to it..

LOL

fair winds and tides

[bgallinger]

I have been watching the oil burn on my Yanmar 3GM30F closely as I motor south on the ICW. I seem to be burning 1/4 cup to 1/2 cup of oil over 8 hours of running time at 2500 RPM. Engine hours total 1200. I would prefer no loss of oil of course, but is the loss I am experiencing acceptable?

[Compass790]

Personally I wouldnt worry about it, only a minor loss as long as there is no other symptoms. Plenty of good info in earlier posts on this thread that pretty much have the subject covered

[a64pilot]

If it starts well, and doesn't smoke enough to be objectionable, there is no issue with oil consumption, in fact once an engine begins to use a little oil, the upper cylinder wear drops quite a lot, meaning that a little oil use is actually a good thing.
Many older Diesels used a little oil when new, it's only with more modern engines that we have become accustomed to no oil useage.

[Cheechako]

Originally Posted by bgallinger

I have been watching the oil burn on my Yanmar 3GM30F closely as I motor south on the ICW. I seem to be burning 1/4 cup to 1/2 cup of oil over 8 hours of running time at 2500 RPM. Engine hours total 1200. I would prefer no loss of oil of course, but is the loss I am experiencing acceptable?

I think it is unusual. It's not a lot, but not the norm with either 3GM30's I had. They rarely needed oil between changes.... although may have at change time. So less than a quart in maybe 150 hours

[George DuBose]

Skylark has a Yanmar 3GM30F. If I keep the engine's revs below 2500, the engine uses very little oil. If I run the engine over 2500 for a day or so, I experience and drop in the level of the engine oil.

The engine has around 1200 hours and has no issues. I am not concerned about this and the engine also burns substantially more fuel when the revs are over 2500.