Yamaha 220hp V6 2 Stroke Oil Leaking out of exhaust prop area

[ShinobiTTZ06]

One of my motors ('86 V6 special) is leaking 2 stroke oil out of the exhaust prop area down the skeg. If the motor is tilted up there is 2 stroke oil coming out of the breather covers/plenum of the lower carbs and there is residue on the bottom of the engine bay. I cleaned all that up and placed the motor in the down position. When I cycle the key on, I get the low oil warning alarm as the remote tank on the motor drained all the way down, it used to hold oil in it all the time. I run twins and the other motor is fine.

I allowed the oil remote tank to fill up, and the oil warning went away. After a few hours I noticed new 2 stroke oil coming from the bottom of the skeg onto the ground, I noticed the remote tank level was no longer full, bled down. I inspected the engine area and didn't obseve any oil in the upper cowl area or around any of the oil line. I cleaned up the ground, came back in a few hours and the oil was on the ground again, and the remote tank was at 1/2 way mark, again, again, until the remote tank is empty and all the new 2 stroke oil is all on the ground.

Clearly the 2 stroke oil is leaking and bleeding down past something in the oil injection pump. There is no oil leaking from the top remote tank cap, oil pump, or lines themselves, as I cleaned the entire inside bottom of the engine bay and it is still clean, nothing on the bottom of the cowl. The 2 stroke oil is going through the oil injection pump or possibly one of the lines and coming out of the exhaust port area and down the skeg onto the ground.

I noticed on the motor that is not leaking that the Keihin oil injection pump was replaced with a Mikuni. The part number for the conversion kit appears to be unavailable. Are the oil injection pumps rebuildable, or does anybody know of a conversion kit that is available? Or could the problem be something else I am missing?

Thanks

 

[saltchuckmatt]

One of my motors ('86 V6 special) is leaking 2 stroke oil out of the exhaust prop area down the skeg. If the motor is tilted up there is 2 stroke oil coming out of the breather covers/plenum of the lower carbs and there is residue on the bottom of the engine bay. I cleaned all that up and placed the motor in the down position. When I cycle the key on, I get the low oil warning alarm as the remote tank on the motor drained all the way down, it used to hold oil in it all the time. I run twins and the other motor is fine.

I allowed the oil remote tank to fill up, and the oil warning went away. After a few hours I noticed new 2 stroke oil coming from the bottom of the skeg onto the ground, I noticed the remote tank level was no longer full, bled down. I inspected the engine area and didn't obseve any oil in the upper cowl area or around any of the oil line. I cleaned up the ground, came back in a few hours and the oil was on the ground again, and the remote tank was at 1/2 way mark, again, again, until the remote tank is empty and all the new 2 stroke oil is all on the ground.

Clearly the 2 stroke oil is leaking and bleeding down past something in the oil injection pump. There is no oil leaking from the top remote tank cap, oil pump, or lines themselves, as I cleaned the entire inside bottom of the engine bay and it is still clean, nothing on the bottom of the cowl. The 2 stroke oil is going through the oil injection pump or possibly one of the lines and coming out of the exhaust port area and down the skeg onto the ground.

I noticed on the motor that is not leaking that the Keihin oil injection pump was replaced with a Mikuni. The part number for the conversion kit appears to be unavailable. Are the oil injection pumps rebuildable, or does anybody know of a conversion kit that is available? Or could the problem be something else I am missing?

Thanks

Read this thread entirely. I believe it's the same problem you have and how people have corrected it

1988 Yamaha 200 ETXG outboard oil leak in cowling - Yamaha Outboard Parts Forum

Ask the experts on our Yamaha Outboard Forum for repair issues, diagnosing problems, links to diagrams, suggestions on buying parts and more. They can answer questions for any Yamaha outboard model or horsepower.

www.yamahaoutboardparts.com

 

[ShinobiTTZ06]

Read this thread entirely. I believe it's the same problem you have and how people have corrected it

1988 Yamaha 200 ETXG outboard oil leak in cowling - Yamaha Outboard Parts Forum

Ask the experts on our Yamaha Outboard Forum for repair issues, diagnosing problems, links to diagrams, suggestions on buying parts and more. They can answer questions for any Yamaha outboard model or horsepower.

www.yamahaoutboardparts.com

Thanks for the response and link Chief. It had a number of problems identified, the one thing that it isn't is the tank overflow sensor as I can watch the remote tank fill up to the line and stop when the key is on. I then turn the key off which stops the auto fill based on the tilt sensor. The oil then gravity drains from the remote tank and comes out the bottom of the skeg, with no leakage or seeping in the bottom of the motor or around the oil injection pump and lines.

I have narrowed it down to the internal pump seal leaking. I have a new pump and kit on order and should have it installed next week and will report back whether it resolves the issue or not.

 

[99yam40]

Just for clarification, the remote tank is in the boat.
the Motor tank is the main tank.

does your new pump Kit come with the in lie check valves in the new lines?
leaking check valves can cause draining, but I think that would not run down the drive shaft like you said.
probably right the oil pump shaft seal is bad

 

[ShinobiTTZ06]

Just for clarification, the remote tank is in the boat.
the Motor tank is the main tank.

does your new pump Kit come with the in lie check valves in the new lines?
leaking check valves can cause draining, but I think that would not run down the drive shaft like you said.
probably right the oil pump shaft seal is bad

So I ordered the Mikuni kit which comes with a new pump. Took it to Marine shop and they told me they had to pull the power head to replace the pump (because of the different length shaft). They also told me they took off the old pump and the shaft was wobbly, and a groove had been worn into it. I noticed that the Mikuni pump they got was wrong part number, so they reordered a different kit and told me they would put me on the schedule when they got the part.

So the former Navy F14 mechanic in me told me I should be able to check this out. Not wanting to wait I found a used Kiehin pump on Ebay that claimed it was taken off a working motor. So, I ordered it. I got it today, inspected, and all looked good. I decided to put in a vice and hook up my electric drill gun to the pump shaft, I hooked up my hand pump to a quart of 2-stroke oil and connected it to the primary oil inlet on top of the pump. I then spun the pump (after priming the oil pump) and I saw the oil start to spurt out of two carb ports at a time from the top of the pump, and how the circuit worked.

I then went out to my boat and looked at the pump and noticed that it had not been taken off by the boat shop. I put the cotter key in the throttle lever to the pump and it was exactly the way I did it. As I took apart the bolts it became more obvious to me that the pump had not been removed and inspected as the Marine shop claimed.

I then filled up the "motor" tank pump (thanks for the clarification), actually I turned the key on, and it pumped up as it should from the remote tank. I did this with the pump off of the motor but still connected to the lines going up to the carbs and the motor tank reservoir. To my surprise it held and there was no leaking at all. I then rotated the lever on the side of the pump backwards and it just started dumping 2 stroke oil out of the cowl and dripping down towards the prop.

The oil was not leaking past the pump shaft it was diverting, gravity draining uphill towards the carbs, and I could see oil leaking out of the bottom port breather cover or plenum that sits on top of the carbs.

So I definitely suspect that this is a check valve issue as you stated. Since the pump lever isn't connected to the throttle lever, I could manually push the pump lever forward and backwards. With the lever forward it is dry, with the lever backwards it leaks like a sieve.

So now I have to carefully remove each line to see which check valve is leaking assuming each individual line has a check valve?

Suppose it's worth a shot trying to clean them out? Or should I just put the used pump in I purchased?

Thanks

 

[ShinobiTTZ06]

Thought I would report back that I kept the throttles in reverse when storing to put the cover on, when I moved the throttle levers to neutral and put the motor up or down, it doesn't leak at all. Afterwards I also took of the top of the oil induction pump and cleaned the check valves out with some brake cleaner and a paper clip. They all moved pretty freely but they are definitely not stuck. I think my oil leak had something to do with some lever adjustments/idle screw and the throttles being left in reverse. I have no leaks all day running the boat.