This is kind of off topic (hope I don't get in trouble, but the list is
very, very helpful), but it does pertain to an old 1/4 ton truck!
I have a fresh overhaul on my '55 M38A1 (it's the military JC5 with a 134 ci
4 cylinder) including fresh overhaul on carb, distributor, fuel pump, new
wires, etc. - bone stock setup. The weird thing is that I have to leave the
choke on (alot) all the time (after being warmed up) to get it to run good
which leads me to believe it's fuel starved. BUT! The fuel pump checks out
for both pressure and flow. When I pull the top of the carb off, the bowl
is full of fuel. Intake vacuum checks out with normal vacuum and no leaks
(no intake manifold - the carb bolts directly to the head). The timing is
set at stock and the mechanical advance seems to work fine. The valve lash
checks out fine. Compression is normal. I've put the carb on a carb
machine and the power valve starts to operate at 7 inches of vacuum (which
should be ok). I can also peek down in the carb throat and see gas
squirting in when I goose the carb (the carb was sent through a sonic
cleaner when overhauled). I'm stumpted. Any suggestions would be greatly
appreciated. I imagine I've missed something here. Or is it normal with
some vehicles to run around all the time with the choke on? It's not that
cold here in Seattle....
Thanks.
Allen in Seattle
'50 3100
'55 M38A1
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