1995 200hp yamah oil leaking carb when tilted

[Donald]

My motor leaks oil out of lower cylinder when
tilted oil tank on motor looks like it is
overfilling

[furballs]

your engine mounted oil tank is overfilling because your remote oil tank pump is not being told to shut off. the problem is most likely a tired float/sender assembly (built in to the cap on your engine mounted oil tank) or an open in the wiring harness between your oil control unit & the remote oil tank. although rare, it could be your oil control unit, but i would consider that last. yamaha shop service manual helps alot...

[Ken]

furballs,
Could Donald's problem be with a stuck check valve in the oil injector pump? I haven't had experience with the oil injector system since my only Yamaha has been a pre-mix, but I read down thru the posts where check valves were a source of oil leakage problem - where oil was actually coming out of the carbs. Whada-u-think?
Ken K

[jb123]

the vent hose on the engine mounted tank will drip unless you reroute the hose, i run them to the rear of the powerhead, cause when tilted, thats the highest point.it just syphons out..... yamaha oversight. try it out, let me know the outcome.

[furballs]

a properly functioning oil injection system (yamaha precision blend, that is) will stop the engine mounted oil tank from overfilling past the top fill line on tank. if the level is no higher than normal, it wont run out out of over flow unless you lay the engine on it's side. the overflow hose being mounted where it is, and has been since 1984, is there for the following reasons;
1. oil running out of the overflow can only happen due to an oil system malfunction . having the overflow hose mounted to the lowest point on intake silencer guarantees that excess oil will gravity feed to the lowest point, hence entering your lowest carbs/throttle bodies & being inducted into engine. this excess oil will burn leaving an abnormal trail of smoke as you are motoring along. this is a pre-engineered telltale sign for the prudent boater that there is a vital engine system that is malfunctioning.
2. excess oil is always preferably burnt than spilled into the deep blue sea & is against the law in most areas.
by rerouting your overflow hose, you may be eliminating the only telltale sign of a potential costly problem......

[furballs]

hi ken,
i have heard of check valves in the oil injection pumps causing leaks, but the pump is located at the lowest gravity point & at the output side of engine oil tank. i can't see it being the cause of the tank overfilling....