Perkins 4-107 air leak

[bobert1953]

I've got a Perkins 4-107 on a Seafarer 38. I've had a persistent air leak in the fuel system. Bleed the engine and she fires up and I'm off. One day later and I've had to bleed again. However, now I can't get the engine to start. I get no air at the secondary filter and the fuel looks clean when I bleed the governer and the bleed screw on top of the anti-stall. However, when I crack the outlet nut on the pump and use the lift pump I get foam and lots of it. That's new. There some fuel at the injectors. But previously when I cracked the nuts I did not get any fuel out till I cranked the engine. Now I get a little spurt when I first crack them. Also, previously I get 'good' white smoke from the exhaust when cranking, now nothing. Ideas appreciated!!!

[bobert1953]

I miss spoke, that should be the fuel inlet at the IP.

[DeepFrz]

I miss spoke, that should be the fuel inlet at the IP.

Is that where you are getting the foam? If so then rig an electric pump from a clean fuel source and try that. If that is where you are getting the foam then the air leak is on the supply side, IP to tank. Check every connection and every inch of line very carefully. Sometimes the pickup tube develops leaks, sometimes its a connection, could be the fuel hose or line or the primary filters.

Edit: or the lift pump itself.

[bobert1953]

I think I've got an issue with the banjo bolt on the secondary. Doesn't appear to be the correct bolt and is too short. See thread, Perkins banjo!

[SkiprJohn]

The banjos on my Mercedes have copper washers and the more you tighten and loosen them the flatter they become. That has been the source of air leaks in the past.

Good luck in isolating the problem. The electric pump and a source of clean fuel other than your fuel tank might help if the new banjo doesn't work.