For the Rebuilders: Help ID source of Fuel leak at Lower crank Head. PICS

[rothfm]

Can anyone in the know provide some insight to my mystery: bit of history.

I took this PH apart a year ago for a measure, and re-ring. I finally mounted it recently, and been testing the last couple days. Runs great, appx 118lbs on all 4, idles super smooth. But I have the ugly streaks starting to come down the sides...I have had them before, and know what to look for...

These are different! I repulled the PH and my base gasket is not the issue, brand new, sealed good-and the leak is not at that area. What I had was greenish blue mix (not exhaust brown/black) coming out the recesses where the steering arm goes into the adapter area, then pooled, and run down the sides. A bunch of it.

after pulling the PH, I verified the Base was sealed nicely and not the cause. I did see Weeping coming from the lower Crank Head plate on the Port and Starboard sides. Actually some was still dripping from a couple of the bolt-heads. This matches the pooling puddles on top of the steering arm upper mounts I saw. So under some pressure, this is where the mix is coming from. What I did not do, when I reworked this motor, was the top or bottom crank Seal, however, I did do the O-rings. It doesnt appear to be coming from the Case split either, but next to it.

Some pics attached....Also note: when I pulled it off and was lowering it to the ground, a fair amout of this mix hit the ground...It didnt come from the carbs and I had the fuel line pinched off. I feel like it was up inside pooled in there possibly.

 

[rothfm]

One tidbit I can add is that the prior head installed was a pre 1985, as such I had to trim the lower unit--on the tip of the driveshaft and "shoulder" area to get the lower unit mated correctly with that older head (commonly done)...that setup had a slight exhaust leak (not fuel) that I thought was the base gasket.

Really seems if that center seal was leaking, I'd see something in that area, around the drive shaft...that area is all dry. The leak is on each side of the Lower Crank head "plate".

Possibly O-rings...Pretty sure I did them, but it was a year ago.

Again, this unburnt blue/green fuel mix.

 

[F_R]

There ought to be some way to pressurize the lower crankcase section for a leak test. Through one of the bearing retainer bolt holes comes to mind.

 

[rothfm]

Hmmm, will look into that before i dig into it again. Too bad as it purrs like a kitten and a great idle. Just to much mix flowing down.

Ive looked at pics of the lower seal, doesnt aeem likely as its on the outside of lower bearing plate seam vs down the hole onto drive shaft.

Im thinking O rings