XL902AM Leaking fuel into oil reservoir

[xl130]

Well you just never know what kind of things you will run into when trying to revive an old castaway saw.

I had expected an air leak on this saw so I went ahead and replaced the crank shaft oil seals.

It Started up great but as soon as it was tilted flywheel side down it stars to increase RPM. Damn I though. Messed up the seal install!

After letting the saw sit in the garage for about a half hour I went to talk into the basement and strip it down again when I heard a giddy sound from the oiler. I thought for sure it must be the crankcase cooling and leaking badly around the shaft seal.

As I was unscrewing the oiler fuel starter to spill out from the automatic oiling port!

After some deep thought with a Budweiser I have come to the conclusion that there must be a break between the two tanks? Fuel tank pressurized and pushes into the oil reservoir?

That would possibly cause erratic fuel flow which may explain the lean conditions when tipped? Possibly the crankcase seal is bad as well?

Lots to think about here. I am contemplating just trying to redkote the fuel tank and hope for the best. That may not work though if the hole is big.....

I may have to go as far as tearing down and splitting the tank to see what’s really going on in there. I really don’t want to do that to be honest.

Any thoughts or experience with this sort of problem?

[rowdy235]

That is odd for sure! Must be a breach between the tanks, as I can’t imagine gas ending up in the oil tank any other way. Possible to borrow an inspection scope to look inside the tank? Probably cost prohibitive to buy for one job but if you have a need I’d imagine could come in handy.

[5terrysupersaws]

 Suggest getting a MityVac-8500 , will pay for itself after a few uses.

Pressure test the fuel tank from the carburetor side.

Pressure/Vacuum test the crankcase ... no guess-work of " was that seal bad/installed incorrectly " .

[xl130]

Found a small crack in the tank adjacent to the bar studs. It must have broken into the bar oil port? I sealed the tank with fuel tank sealant. It seems to hold gas now. I will still need to pressure test the fuel tank but I think it’s fixed.

I also used my recently acquired Mityvac on the crankcase. Found badly installed oil seals, a leak at the reed block and a poor seal at the ignition backing plate.

Thanks for the encouragement to purchase the Mityvac 5 T’s! It’s truly a must have for building and repair. I would have never guessed all those leaks!

[xl130]

What is the thread size for the filler cap on a 902AM? The tank threads are full of fuel tank sealant. I’ve tried picking it out but that is causing more damage than I prefer.

I thought that I may be able to thread a pipe in slowly or something similar to knock the hardened sealant out of the threads?

I tried to use acetone but that doesn’t seem to be as effective as I hoped.

Any ideas? I can’t imagine that I’m the first person to have the problem??

[onlyhomelites]

I have no idea if it's a common pipe size or not. I've had tank sealant do what you're talking about; I've had the best luck with a dental pick digging it out. A real PITA for sure, but as you've said, acetone and otehr solvents won't touch it. Which I suppose is good, since we want the tanks to hold fuel once they're resealed!

[xl130]

I think that the tank might have had something corrosion in it at some point or possibly white death. I think that the threads have been corroded. It seems to have affected only the bottom thread. For a temporary fix I just put a thick gasket in the filler cap.

Put a bar and chain on it and did the first cut with the new piston & rings. So far so good! Fun saw.

[fossil]

Nice Trevor

[xl130]

This saw had some unique challenges. I think it was shelved a looong time ago. Probably because of the hole in the tank.

Hopefully the rebuild holds up. Now I have a saw to run against the 77cc Pioneer 3200 I’m picking away at.

[tangobravo]

Is this one of the black painted rear handle spine saws? I have only seen that on an Xl-800 and I think a blue XL-1. Unusual feature.

[xl130]

Yes it does have a black stripe at the rear handle. The side with the trigger lock is a NOS replacement so the black is a bit more noticeable. The paint on the other side is worn.

[xl130]

I put the first tank of fuel through the saw yesterday. 20” bar on an old blowdown tree. Pretty impressive for a 50 year old saw design. These saws really have bottom end grunt. I’m happy!

youtu.be/teoOn8Kh4fA