The Cessna 120-140 Association Forum

Noticed a fuel leak a few days ago, tracing it to what I thought was the gascolator gasket on the old Koehler unit. After many hours of head scratching, removing the line from the valve and pulling out the entire tubing assembly, looking for leaks, re-assembling, still finding leaks, it all finally boiled down to some weird cracks inside the aluminum casting unit, on the inbound fuel side. Couldn't see anything on the outside of the unit but it sure showed itself on the inside threads (see pic). No amount of fuel lube sealant was going to fix it. There may be some magic sealant out there but I don't want to mess with it too much. Anyway, have a loaner for the moment, and Tim Mix is looking for a 'spare' but if anyone has one laying about let me know! I just really need the casting body.

Check with Todd Littfin at Smokin Rivet Airparts.
715-450-three,six,eight,nine.

He probably has one at a good price.

Rick

If all else fails, I’ve seen them on EBay.

David, where was the leak showing up? On the outside of the casting?

David, where was the leak showing up? On the outside of the casting?

Actually it did seem to show up on the outside of the casting. I did a dye-pen test and could not find a crack on the outside. It just seemed to 'weep' through, or some such capillary thing.

My sense is that when I replaced the damaged fuel line from the valve to the gascolator some 20+ years ago I probably tightened the back fitting too much or didn't use enough fuel lube, who knows.

Regardless, Todd is looking for a salvaged unit. No word from Tim Mix yet. Yes, I do see them on Flea-Bay but would like to help the home team if I can! The loaner I have is from a project that is quite a ways out on completion so I am not in a dither at the moment....

Here's a potential answer to the leaking. I installed this some years ago. Takes about 10 seconds to check during annuals.

https://www.stevesaircraft.com/gascolator.php

Ray,

I looked into Steve's gascolator. Apparently there is quite a bit of work involved i.e. a new fuel line from the valve, a new mount, another hole through the firewall, none of which is insurmountable. They are nice units, $300 plus the new line and bracket.

I got lucky and Todd at Smokin' Rivets got back to me and offered to sell me a servicable Koehler casting for $20 plus shipping.

Great! Good luck with the gascolator. You are correct that Steve's unit was not easy to install, but the instructions were easy to follow and I've been happy with the unit, particularly at annual time. No more safety wiring!