1988 Yamaha 200 ETXG outboard oil leak in cowling

[makojoe238]

I have the above motor that is leaking fresh oil from the bottom intake manifold. It is not leaking from the cap on the engine mounted oil tank. It is not leaking from any injection hoses leading from this tank. The engine mounted oil tank cap on top was installed correctly with all things inside aligned as required by the shop manual. It is not leaking from the over flow hose at the top of the engine oil tank. I removed the carb cover and can see the small pinhole on the bottom of the manifold where the oil is coming from. I believe this hole and hose connected to it acts as a collector of unburnt oil and it gets sucked into the intake at start up and is burnt up?
I see there is an oil pump converson kit available for this year motor. I also see there are "check valves" in oil lines of the diagram of this conversion kit. What is the purpose of the oil pump conversion kit and do these check valves stop the oil from flowing into the manifold area? Can I just install these check valves and solve the problem? I really love my engines and they run great for how old they are. Any help would be appreciated.

[Bullet1750]

It sounds like the oil tank is over filling it has an overflow line which leads to the intake manifold...........I could be wrong

[Tucker]

Joe, having a problem believing there is a hole in the intake manifold, sure you don't mean the plastic silencer?? The overflow from the oil tank connects to the bottom of the silencer. If you had a hole in the manifold you would have a vaccum leak. Sounds like Yam upgraged the oil pump. The check valves keep the oil from draining back.

[makojoe238]

Joe, having a problem believing there is a hole in the intake manifold, sure you don't mean the plastic silencer?? The overflow from the oil tank connects to the bottom of the silencer. If you had a hole in the manifold you would have a vaccum leak. Sounds like Yam upgraged the oil pump. The check valves keep the oil from draining back.

Yes it is the silencer...sorry not the manifold. The cover is plastic but the intake or air box is aluminum and that is where the tiny hole is that leaks oil into the bottom of this air box. The hose that is connected to the silencer/air intake at the bottom does not go to the overflow it is goes under the block and is connectec to the bottom of the block to a nipple...I think.

[Tucker]

I got newer vintage motors so my setup may be different. Before I went to premix and had oil pump, res, etc., my silencer had 2-small vent nipples on the bottom. 1-went to the oil reservoir and another went to crankcase vents. Is your crankcase vent leaking oil?

[shallowmindedguy]

Do you have any running issues?
Is the motor smoking?
Can you determine if it is 100% oil?

One thought is that it might be oil/fuel mixture and you are starting to see a small leak in a fuel pump diaphram. This would be leaking fuel into the pressure area of the block and it some times shows up in the intake area.

Just had this problem. Pretty easy fix.

[arodri82]

Oil Leaking

I had the same problem, CK the adjustment rod of the oil pump. If you adjust the carbs idle screw you have to adjust the the oil pump rod. If stays open it will leak I have an 89 200

[makojoe238]

Do you have any running issues?
Is the motor smoking?
Can you determine if it is 100% oil?

One thought is that it might be oil/fuel mixture and you are starting to see a small leak in a fuel pump diaphram. This would be leaking fuel into the pressure area of the block and it some times shows up in the intake area.

Just had this problem. Pretty easy fix.

It's straight unburnt oil. I replaced all my fuel pumps last fall and the engine runs fine no excessive smoking.

[makojoe238]

Thanks I'll take a look at the rod.

[Tucker]

I had the same problem, CK the adjustment rod of the oil pump. If you adjust the carbs idle screw you have to adjust the the oil pump rod. If stays open it will leak I have an 89 200

I think this would cause smoking and running issues. He has an oil leak. Mako did you confirm the exact hose it's coming from. Tank overflow? Case vent?

[jb123]

does your motor have an oil control unit ?

[BigNiner19]

I have this exact same problem on a 1989 Yamaha V6 Excel 225. Excessive unburnt outboard oil leaking in the cowling, it will puddle up and then leak down the side of my motor.

Cannot see where it leaks from. I clean everything out with a hose and degreaser to try and spot the leak. Can't see anything. There appears to be no leaks from the reservoir.

Hope you find the problem, driving me nuts.

Cory

[Tucker]

Bringing this to the top. Guys does it smell like it's been combusted? Is it blue 2-stroke oil? Does it have gas in it? Confirm it leaks when motor is running and not tilted up.

[throrope]

I had the same problem, CK the adjustment rod of the oil pump. If you adjust the carbs idle screw you have to adjust the the oil pump rod. If stays open it will leak I have an 89 200

Thanks, Gonna go back of this one for sure.

[Bullet1750]

OK its just happened to me, engine runs fine no smoking friday then did not use the boat for 3 days and the oil has drained out of the top tank through the air box and into the cowling, perfectly clean. It has to be siphoning due to gravity through the injection pump, will pull it down during the week to sus it out. This is the first time in 25 years this has happened. Motor is a 220HP 1986.

Craig