From: chance wolf (chance_wolf@shaw.ca)
Date: Wed Jan 21 2004 - 11:27:27 PST
----- Original Message -----
From: "Buzz" <buzz@softcom.net>
To: "Military Vehicles Mailing List" <mil-veh@mil-veh.org>
Sent: Wednesday, January 21, 2004 9:22 AM
Subject: [MV] SIMILAR MUTT M884 FUEL SYSTEM PROBLEM
> I also notice that with the air intake hose disconnected at the carburetor
when I turn the engine
> off 3 or 4 drops of fuel come out of the carb. I've set the float to
specs and even tried lower
> than spec but the drip still persists.
>
> Does anyone else have/had the same problems?
> How about the A2 owners?
Best thing I ever did for my A2 was buy a rebuilt carb from the fellow
advertising in "Supply Line" (can't remember his name dammit - in Florida
somewhere, I think.) A lot of the problems went away. Before that, the
hard-starting thing would frustrate the hell out of me, and I changed fuel
pumps thinking it might be due to defective check-valves - lines thinking of
pinholes - and vent-lines just for the sake of completeness. The worst carb
of the lot seemed to actually percolate the entire contents of the
float-bowl into the manifold (and thence into the cylinders) when left for
any length of time, which resulted in a few nasty dry starts and an awful
lot of frustration. I don't know if that's what was actually occurring or
not - but formed a 'best guess' at the time. Regardless, changing the carb
with the good rebuilt one seem to solve that particular headache and an
awful lot of others besides.
The other annoying thing was that there's a venturi tube in the Zenith carb
which likes to get narrowed/clogged/blocked. If yours is getting to the
point where you need to do something about it, you'll notice hard-starting -
and either a very poor/erratic deceleration curve, or outright backfiring.
Be *very* careful extracting this tube when you examine it for two reasons:
1) If you use an unkind tool, you'll distort the venturi opening
2) The little o-ring/gasket underneath either likes to get lost - stay
behind in the hole - or warp/twist and stay behind in the hole to be plunged
into the depths of the carb when you reinsert the venturi.
(Sometimes the little gasket/o-ring isn't even present due to some previous
carelessness, and if that's the case, you should probably find one or make
one. )
Most of the Canadian 151A2's like mine ran the last part of their lives with
tandem fuel filters in successively fussy micron ratings, yet *still* got
the venturi blockage periodically. That's one of the first things I look
for when having carb-based performance problems with my own 151 or any of
the ones at work, and it's been the case enough times to warrant mention.
I've also had two vehicles with pickup-tube problems. One was pinholed
halfway up the in-tank pickup tube, and the other was poorly soldered or
fractured (don't remember) at the point the tube mates with the top fitting.
Another had some sort of material trapped in the 'elbow' of the pickup tube
where it goes into the fitting, which would then randomly allow or block the
flow of fuel as the whim took it (looked like pine needles, but the tank
appeared clean inside.)
Anyway, your 'drip' thing could be the herald of the sort of 'percolation'
problem I figured I had - but as I said, I never 'proved' it, and replaced
the carb instead.
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