SailNet Community banner
1 - 1 of 1 Posts

8,867 Posts
I have a Yanmar 2 QM15 with about 500Hr since it was rebuilt. The oil pressure
is fine when I first start up 40 psi and its ok for about 2 hours running at
3000 rpm. The oil pressure starts to drop below 20 psi. The alarm goes off and I
reduce the rpm to 2200 or less and the alarm stops and the pressure is low but
it seems ok. Its around 18 psi. If I run the rpm back up the pressure goes up a bit but not enough. This problem just started up, and I at a loss
about to do about it. I don't think its the sensor because it works fine when I
first start up.
I've changed the oil and filter and it still happens. I'm not using a Yanmar
filter but that should not matter, I use shell oil rotella t 15w 40 and have
been using the same for years. I know the original owner of my boat had the
same type of problem and thats why he rebuilt the engine. I can't get in touch
with him. I' looked on the web and have found no answers. I have put the 500hr
on and have been good about all maintains, Ive had no other problems with it
other then its very hard to start when its cold out, below 50F but thats not a
problem now.
Any ideas would be helpful, I'll be in a place where I can get parts this week.

Thanks Stephen
I have read about some filters causing that problem, maybe try a Yanmar filter?

Possibly, the electric sensor is heat sensitive, Maybe try a new sensor, or temporarily hook up a mechanical gauge.

Or perhaps the pressure relief valve is failing, maybe effected by heat?

Or maybe the oil pump is getting tired?

If none of the above, maybe the engine bearings are somewhat "loose" after heating.

"Rebuilt" ? whole lot of variables there. Rebuilt by whom & what parts were replaced?
Paul T
1 - 1 of 1 Posts