86 johnson 25 hp air leak

[DougyB]

J25tecdc, this things killin me guys, I thought I had it beat after a short run on the lake, and the air leak came back very quickly. As stated new tank, lines, fuel pump's(yes I bought two new ones just to make sure), carb rebiuld etc. I made this video just to check my work and also inquire about the fuel barb I replaced and its inside hole diameter effect on the vacuum of my fuel pump.

 

[oldman570]

Re: 86 johnson 25 hp air leak

Have you tried reversing the 90 ellbow on the lines? some of the motors have a one way valve built into the fitting. This could be what is causing your problem. Worth a try. If it still has trouble the fitting you replaced might be the trouble, by letting the crankcase suck to much vacum. Tou could place a smaller pice of hose inside the one you have on there now and reduce the size down to what the old fitting fitting was, or call SeaWay Marine and see if they have a replacement fitting that broke.
Oldman570

 

[nwcove]

Re: 86 johnson 25 hp air leak

jmo, but id replace the cable ties on anything " suction " related ...right down to the tank,with hose clamps just to rule out an issue there. if the female omc connector hasnt been replaced, its another spot to look for air intrusion. i dont think the larger barb on the block would cause you any issue....but not 100% sure on that.
( are you sure its not an ignition issue?)

 

[DougyB]

Re: 86 johnson 25 hp air leak

oldsman, i'm guessing your talking about the t-connector for the vacuum lines? I will call seaway tomorrow, thats a good idea.. and maybe ask some other salvage places as well.
nwcove, I just got fuel line ties for every fitting, thats what the marina suggested on anything inside the bonnet. And by female omc connector, which connector do you mean? Are you talking about the male connector on the side of the engine? I'm pretty sure its not ignition because both coils shoot gaps and I can keep the boat running by constantly pumping the bulb

Had the carb rebuilt, my other idea was maybe the carb bowl wasn't sealed good, the brown gasket seamed wet sorta

 

[DougyB]

Re: 86 johnson 25 hp air leak

I just read something on an old thread that says the barb fitting/vacuum line im talking about does nothing more than dump extra fuel runoff into the lower engine block, thus not affecting engine flow... Is this true?

 

[DougyB]

Re: 86 johnson 25 hp air leak

Any idea on the truth of this??? that the bottom vacuum line simply dumps excess fuel into the bottom of the engine and doesn't affect running...

 

[oldman570]

Re: 86 johnson 25 hp air leak

Mwcove is talking about the conector on the fuel hose . They have rubber O rings that can get damaged from hooking the hose to the motor over time, an will let air leak in to the fuel supply, at the connections at the motor and tank . This is a very common problem on most all outboards. The barb fitting and hose are adding extra fuel at startup if the carb dose not have a butterfly in the carb for the choke.
Oldman570

 

[DougyB]

Re: 86 johnson 25 hp air leak

just wanted to let you guys know its fixed. I took off the carb, made sure the bowl was super tight to prevent any air leaks from the gasket. I then put new fuel line zip ties on every connnection. I also replaced the bottom barb that goes into the bottom of the crankcase with a new one that had a smaller hole (maybe the hole was too big and let needed fuel drain from the carb, I wouldn't know). Boat runs great now.

 

[nwcove]

Re: 86 johnson 25 hp air leak

great to hear you got it sorted out dougy.!