1200 motor oil leak

[Adam5oh]

Hi All,

I've got a 1200 motor (non pv) that I'm having some issues with. I pulled the plugs to do a compression check and noticed a lot of oil visible on the surfaces of the pistons. If I stick a rope into the cylinder it comes out covered in yamalube. When cranking the engine without the plugs oil comes out (not a huge amount, but enough to make a mess). Compression reads 120 across all 3 (other engine reads 90, it is a LS2000). The next day after doing this I checked the hull and had some oil pooling in the bottom. I traced it up to the engine and it looks like it might be coming from the rear seal area. Any ideas?

Thanks!
Adam
1999 LS2000

[Technical Support]

Re: 1200 motor oil leak

The rear seal should not be leaking, there are oil check valves that control the oil into the case, they may be stuck open causing the oil to keep draining into the engine.

[Adam5oh]

Re: 1200 motor oil leak

is this something that the motor has to come apart for or is it part of the oil pump?

[Madfish]

Re: 1200 motor oil leak

I could be wrong, but I believe the check valves tech adm is talking about are in the 3 oil lines that go from the oil pump on the front of the engine to each of the 3 carbs.

But how does that explain oil on top of the pistons? Normally, this would indicate worn piston rings/blow by, but you say compression is 120 psi on all 3 cylinders, which is excellent.

I would do this: Remove the oil pump, get a block off kit from SBT (about $15). Then, where the 3 oil lines connect to the carbs, cut those lines off leaving about 1 inch of oil line on each carb, then put a #6, 3/4" stainless screw into the ends of those oil lines to cap them off.

Then go with premix, 50:1 ratio, and then you have control and you know for sure your engine is getting the correct amount of lubrication it needs. No more than it needs, no less.