What's leaking from my johnson???

[NORTH81]

Just replaced fuel lines and power packs. Started her up and this is what happened...

 

[coolbri70]

Re: What's leaking from my johnson???

that would likely be the 2 stroke oil it doesnt burn with the gas, it stays behind to lube the motor, looks like the exhaust gasket may be leaking as normally it would only be dripping from your prop and exhaust relief ports

 

[emdsapmgr]

Re: What's leaking from my johnson???

The powerhead base gasket is failing. A common V4 crossflow malady. The gasket's cheap, but you'll spend 3 hours removing/re-installing the powerhead to replace it. While the dirty consequences are very visible, what you don't see if the exhaust gas that's leaking into the cowling. That exhaust will get sucked back into the carbs when running. That's the best reason to get this repair done sooner, rather than later.

 

[coolbri70]

Re: What's leaking from my johnson???

yep, what he said, base gasket, some reason i was stuck on exhaust, thats where its coming from

 

[TrueNorthist]

Re: What's leaking from my johnson???

"What's leaking from my johnson???"

I wouldn't shout that out in a bar if I were you...

 

[NORTH81]

Re: What's leaking from my johnson???

Truenorthist, I tried that once and got tossed Emd and cool, I went out and looked under the exhaust housing cover. It seems that it is leaking from the gasket between the exhaust housing and powerhead. Is this what you mean by base gasket? Looks like I will be tearing her down. Fun Fun. So... since I am going to be that far into tearing her down, are there any other things you would recommend I do that can only be done while the engine is torn down? Also, do you have an idea of what the powerhead weighs on its own on a 140? Just curious whether I will need to get a cherry picker or if I can muscle it off. (though I have a pretty good idea of the answer)

 

[classiccat]

Re: What's leaking from my johnson???

Truenorthist, I tried that once and got tossed Emd and cool, I went out and looked under the exhaust housing cover. It seems that it is leaking from the gasket between the exhaust housing and powerhead. Is this what you mean by base gasket? Looks like I will be tearing her down. Fun Fun. So... since I am going to be that far into tearing her down, are there any other things you would recommend I do that can only be done while the engine is torn down? Also, do you have an idea of what the powerhead weighs on its own on a 140? Just curious whether I will need to get a cherry picker or if I can muscle it off. (though I have a pretty good idea of the answer)

:facepalm: title :lol:

the powerhead of a recently acquired 70Hp (3cyl) is danging a cherry picker as I type...head is heavier than I thought...at least 140# (210-220# total weight).

While the head is off, figured it would be a good time to do a thorough paint job, pull the the cyl head and exhaust...as well as add a tell-tale. perfect time since I have full access to all of the bolts...plus I don't know what's lurking in the cooling circuit (some serious neglect from the PO).

 

[emdsapmgr]

Re: What's leaking from my johnson???

Not sure if this is an issue with the V4 engines or not. OMC has made two base gaskets for their V6 flatback crossflows. One is a thin paper gasket, the other is a thick metallic-looking one. The thin one is called out in their factory parts lists. The other part number is obscure and hard to locate, part numberwise. When you get a look at your new base gasket, make sure it's not the paper one, or you'll be redoing it in again in a year to two. Also, you might consider leaving the lower exhaust covers off for a few weeks. Run the engine through a few heat/cool cycles, then retorque it and then install those lower covers.