Please help me find this oil leak?

[Salmonseeker]

Okay, I posted this I while back. Between trips when the boat was stored on the trailer with the motor down. I would find a small puddle of 2-stroke oil on the anti-ventilation plate. It was dripping from the motor and running down the inside of the upper casing and ending up on the AV plate.

I suspected the OMS (VRO) pump. I removed the pump and inspected it over the winter. I could not find the a leak. The screws seemed a little loose so I tightened them a little. All the hoses seemed okay. I put it all back together. Pressurized the fuel and then the oil system. Did not see any sign of a leak.

Took the boat out for the first run of the season after the repairs this past Saturday. I went to look at the motor today. The motor was tilted up. I opened the cowl and was Pissed. There was about a tablespoon of 2-stroke oil siting near the front of the casing below the carb. It seemed to be mostly oil. I could feel oil all over the bottom of the air silencer below the OMS pump. I removed the air silencer cover and the gasket was saturated with oil. There was a coating of oil and gas all over the inside of the air silencer.

I suspected the oil might be coming from the carburetor. My only thought might be the reeds are causing a lot of spitback, but the intake passage of the Carburetor had no residue on it. I think this is not an option since this oil was leaking last year with the stock reeds which were in perfect shapen when I removed them. I installed Boyesen Reeds when I took off the OMS pump.

Is it possible for the carbs to be leaking oil or a fuel oil mixture through the carbs when I am tralering the boat? I normally should off the motor and tilt it up almost immediatly. If I check for the leak the same day I will not see anything. Just when it sits for a few.

I know it is leaking from the air silencer just below the OMS pump. Where is it coming from?

Please help, Thanks

 

[Kevin W]

Re: Please help me find this oil leak?

The VRO mixes the oil and gas so if it is still dry most likely you do not have an oil leak...
It is a gas leaking.
the gas quickly evaporates and the oil is left.
It is somewhat normal for some gas to spill out when tilted.
Spitting back may be an issue though.
Reeds, timing ... that i am not an expert on that.

 

[emdsapmgr]

Re: Please help me find this oil leak?

What year and model engine? Not unusual for gas/oil to drip from the carbs when tilted. Usually it will collect in the bottom of the air silencer, then be drawn back into the engine for combustion through the crankcase suction hose at the bottom of the silencer. If you have this hose, make sure it is connected. If you have a saturated gasket between the halves of the airbox, replace it. Some of the DFI models had problems with the airbox design and leaked.

 

[Salmonseeker]

Re: Please help me find this oil leak?

The motor is a 2004 Johnson 50HP 2 stroke. The drain hose is connected at both ends. The gasket was brand new. I just replaced it and only ran the motor once. Now the new gasket is saturated and I believe leaking from there.

I checked the drain hose, it is not plugged.

I know some fuel residue in the air silencer is normal, but I don't think there should be this much.

Any idea what would cause too much?

 

[Salmonseeker]

Re: Please help me find this oil leak?

I just looked at the motor again. I think I found the source of the leak. I tilted the motor all the way up with the air silencer off. I primed the fuel line. The carbs were not leaking anything. There was oil leaking from the drain hole in the silencer that runs to the crankcase.

It must be leaking out when the motor is tilted up while trailering it home after it is ran. Is it possible that the OMS (VRO) pump is putting out to much oil and not being burned up and sitting in the crankcase? I do notice that it will occasionally smoke more than normal for about a minute then go back to normal. Almost like it is getting more oil at times than others. The motor is not very old so I would not expect the OMS to be failing already.

I am pretty sure it is leaking from from the crankcase into the air silencer when the engine is tilted. What would cause this much oil in the crankcase?

 

[Kevin W]

Re: Please help me find this oil leak?

one possibility is the drain hose at the bottom of the silencer to the manifold is plugged.
If the engine was fogged at the end of the season maybe some of the fogging oil mixed with the gas and oil to form a plug in the hose or even in the nipple on the manifold.
if the engine appears to run as normal that would be my guess.

 

[Salmonseeker]

Re: Please help me find this oil leak?

Hey Kevin,

Thanks for sticking with me on this. I just checked the drain hose with a piece of 30lb test fishing line. It is not clogged. I also turned the motor over by hand and the drain hole in the silencer shot out some oil and fuel mixture.

I did fog the motor and the end of the season and removed the VRO thinking it was leaking (found no leak). According to the manual I am running the first tank of fuel on pre-mix until I verify the VRO is working. So maybe it is just a combination of left over fogging oil and running double the oil ratio into the motor. This could be leaving so much oil in the crankcase that is has nowhere to go.

This problem was happening last year though but not as bad. That was why I thought the VRO was leaking.

I did suspect that the carbs were running rich all last year. The motor ran great but seemed to smell like unburnt fuel occasionally. I troll alot just above idle for hours at a time. I do run it above 5000 rpm for at least 10 minutes after the trolling. Maybe they were running rich at idle and in doing so mixing extra oil and leaving it in the crankcase. Then when I would tilt it up it would drain out into the air silencer via the drain hose.

The only other thing I could think of is the VRO is pumping too much oil, but this does not agree with my oil usage. I would say I used very little oil, just over a gallon all season.

Is there an easy way to tell if the carbs are too rich at idle?

Thanks, Jay

 

[Kevin W]

Re: Please help me find this oil leak?

I am not a VRO expert but... i would watch the spark plugs.
if its fouling the plugs bad you are getting too much oil.

another thought.
do you ever run the engine out of gas??
you know unplug the gas and run til it stalls?

I do know the VRO will pump a bunch of oil in the carbs if you run it dry.

It is possible the way you are using it extended trolling is causing a buildup in the manifold.

maybe if after you stop trolling maybe give it a 5-10min+ run at a moderate throttle and it may eat up the excess buildup.

 

[Salmonseeker]

Re: Please help me find this oil leak?

No, I don't disconnect the fuel line and run the motor. I do usually run it at full throttle for a bit after trolling.

I will mess around with it once I burn up all the premix in the fuel and fill the tank with fresh fuel. It is hard to really test it when I am running twice the oil.

I checked the plugs and there is still some brown oil left on them. I am assuming this is the fogging oil. The 2 stroke oil I am using is blue.

I will figure it out, I am just glad to know that it is coming from the crankcase and not the VRO. I would like to keep the VRO hooked up and was worried it was leaking.

Thanks for your help, Jay

 

[Kevin W]

Re: Please help me find this oil leak?

a little too much oil is generaly better than not enough.

I have that running seafoam in the gas as a stabalizer/decarber.
it seems to keep the plugs cleaner and i bet it keeps the reeds cleaner too.
I personaly have not seen miricles but there are alot of people here that swear by it and mine has been running pretty good with it.

I have a VRO on mine that is pretty old so i mix my fuel at 100/1 too.
If it my VRO fails i could get slowly home without paddling.