Here is my problem,The oil tank inside the engine compartment drains down after two or three days sitting with motor tilted down ,oil leaks thru the lower carb onto ground. When tank is refilled to run motor with hosepipe, oily water and white smoke blows out of the prop for 5min. till it's clear and no oil or smoke is present. motor runs great.
The older engines didn't have the inline check valves on the oil lines. These prevented this problem when the oil bypassed the pump and flowed into the intake. You can get the check valves from any Yamaha dealer. They ain't much and will prevent this problem. You will need four of them and you just cut the lines between the oil pump and the intake and stick them in.
I had that problem too. There are check valves in the oil pump. Sometimes they need to be reseated. I would pull the pump, clean it out, and reseat the balls in the check valves.
Leave the oil pump alone. The pump isn't a owner serviceable item and there isn't any check valves in the pump. Just a little cylinder that goes round and round with a hole that lines up with the different oil holes. The inline check valves were added with later models to address this problem.
Ken, I have a 1988 V6 Yamaha and there ARE check valves in the oil pump. One of them became stuck in the open position causing oil to flow through the pump and into the intakes.
Where I was coming from rbu, is we don't need owner's messing with their oil injection systems. Those check valves never worked well and that's why Yamaha starting installing the inline check valves. If an owner goes and messes with the oil pump and doesn't do it right, the engine is trashed. We don't need that problem. The inline check valve is an easy solution that won't cause problems with the injection system and can be owner installed.
Have you read some of the other posts? There are guys messing around with more than just the oil injection I hear what you are saying Ken. That's a smart move to install inline check valves. I'm just trying to share some of the experiences and solutions that I have had. I know that I have been stumped and frustrated more than once.Anyway, I hope this guy gets his problem fixed.
Thanks for the info. I priced the check valves (10.45 each) Can I disconect the 4 lines on the intake and see which one or ones are leaking ,or just add the new valves. There are splice connectors in each line , do I replace them with check valves.
1987 yamaha 115 oil injection system
Linear Mode
