Allen,
I think Joe has hit it on the head. The only other test is to throw a rag
over the carb and cut back the choke. If it still runs you are sucking air
from somewhere else cause there's a king size vacuum leak (again, possibly
a mis-alligned carb gasket.) somewhere in the system.
Bob Heil
'51 3600 in pieces
"joe"
<chevy1@jps.net> To: "Allen Jones"
<jonesal@u.washington.edu>,
Sent by: <oletrucks@autox.team.net>
owner-oletrucks@auto cc:
x.team.net Subject: Re: [oletrucks]
Choke On All The Time
Question
05/09/01 06:03 PM
Please respond to
"joe"
The only thing that I can think of is maybe some of the transition passages
on the carburetor are plugged and not dumping in their fair share of
additional fuel when called upon.
Did you match up the gaskets from old to new before tossing them out? I'm
thinking that a passage either between the base and lower body or the body
and upper section is covered by the gasket.
I guess the quick check would be to drop on another carburetor to see if
that cures the problem.
Joe
-----Original Message-----
From: Allen Jones <jonesal@u.washington.edu>
To: oletrucks@autox.team.net <oletrucks@autox.team.net>
Date: Wednesday, May 09, 2001 9:53 AM
Subject: [oletrucks] Choke On All The Time Question
>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
>oletrucks is devoted to Chevy and GM trucks built between 1941 and 1959
oletrucks is devoted to Chevy and GM trucks built between 1941 and 1959
oletrucks is devoted to Chevy and GM trucks built between 1941 and 1959
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