91 johnson 90 dirty gas leaking from under cowling ?

[arthurj12]

hello my engine is leaking dirty gas stuff from under the smaller plastic cover under the engine there is no fuel inside of the cowling just a leak when i run it and leaks for a bit after running.

 

[emdsapmgr]

Re: 91 johnson 90 dirty gas leaking from under cowling ?

The plastic airbox on the front of the engine is designed to catch any excess fuel, oil that may leak out of the carbs. That excess will accumulate in the bottom of the airbox, where it will get recirculaterd back into the bottom cylinder and combusted. The factory installed a small hose between a hose barb at the bottom of that airbox and a hose barb on the front of the engine. If the hose is missing, or one end becomes detached, you will get fuel/oil leaking onto the front of the lower cowling.

 

[arthurj12]

Re: 91 johnson 90 dirty gas leaking from under cowling ?

ok ill check for the hose thx

 

[arthurj12]

Re: 91 johnson 90 dirty gas leaking from under cowling ?

hello i got my airbox off and it looks hooked up any more ideas?

 

[emdsapmgr]

Re: 91 johnson 90 dirty gas leaking from under cowling ?

There is supposed to be a thin cork gasket between the two halves of the plastic airbox. 321722. If it is missing, oil can leak out of the airbox. Check your fuel delivery hoses for leaks at the hose joints. When the factory put that engine together, they used plastic ty-straps as clamps on the fuel system. Once the hoses get older, the clamps tend to lose their clamp load as the hoses shrink with age. You may need to replace some of the clamps. Bombardier makes a newer style clamp which performs better in this applicaton. You use a pair of pliers to clamp them on-pretty simple.

 

[arthurj12]

Re: 91 johnson 90 dirty gas leaking from under cowling ?

i checked out all the fuel lines all seems good there is no fuel in the inside of engine . ill explain my problem better on the outside of engine from under the small cowling that wraps under the engine dirty fuel/oil is leaking from there just a very small leak ???

 

[emdsapmgr]

Re: 91 johnson 90 dirty gas leaking from under cowling ?

If you have an oily substance leaking at that location, You may have another issue: it is possible that the powerhead base gasket is failing. A common problem on older crossflow engines. When that base gasket starts to deteriorate, it will leak unburned exhaust oil between the powerhead and the exhaust adapter. It's not a fatal issue-but you should tend to it sooner, rather than later. When that gasket gets really bad, it will leak exhaust gas into the cowling. That exhaust gas will get recirculated into the carbs during operation. Best to get it fixed before that happens.

 

[arthurj12]

Re: 91 johnson 90 dirty gas leaking from under cowling ?

that sounds like it ill take off the cowling and take a look anything i can do tighten anything up ??

 

[emdsapmgr]

Re: 91 johnson 90 dirty gas leaking from under cowling ?

Not if it's a failed base gasket. About a 3 hour job, plus a gasket: 342513, about $ 13.

 

[toddschubert]

Re: 91 johnson 90 dirty gas leaking from under cowling ?

Should be tended to at some point but mine does the same thing. I just keep it wiped down every trip to see if it gets any worse. Sometimes none comes out at all. I've been running for the past 8 mos. like that and has not appeared to have gotten worse.

 

[arthurj12]

Re: 91 johnson 90 dirty gas leaking from under cowling ?

ok how much would u say comes out during a day of use ???

 

[toddschubert]

Re: 91 johnson 90 dirty gas leaking from under cowling ?

Maybe a 2-3 inch drip but sometime
More like to Lower unit

 

[arthurj12]

Re: 91 johnson 90 dirty gas leaking from under cowling ?

ya about the same have u ever taken lower cowling off and looked to see where its coming from???

 

[toddschubert]

Re: 91 johnson 90 dirty gas leaking from under cowling ?

I'm fairly certain its power head gasket where exhaust gases are blowing up into top of Lowe unit and or crank case fuel making its way out which seems like it would be cleaner looking
I've had the big guns on this site say it is inherent prob on crossflows and no big deal but I gotta say any leak is a bad leak. Just because I let it ride for now doesn't mean I'd suggest it

 

[arthurj12]

Re: 91 johnson 90 dirty gas leaking from under cowling ?

alright i think i read that to thx alot ill check it out get it fixed