Re: [MV] M-37 Starting Problems

Alan Bowes (Inbox@todacosa.com)
Thu, 28 May 1998 10:52:36 -0600

Hi Henry,

As Steve mentioned, this is a vacuum-operated accelerator pump, so it won't squirt any fuel when you pump the gas without the engine running. There may be a squirt when you shut off the engine and vacuum abates, but I've never had a problem with the Dodge engine flooding or even hesitating when
restarting it as the result of this one squirt. Maybe some other engine/carb combos (M151 perhaps?) are more susceptible to it. I don't have any experience with the 151.

A little more data might be helpful:

Have you checked your new spark plugs? Check them right after a nice long run. If they are carbon fouled, it could signify a fuel mixture/choke problem.

Do you notice any black smoke at times other than while starting?

Is the choke and linkage in good shape? Is it adjusted properly to allow full choke opening?

Here are two VERY common choke problems:

1) If the choke is worn or misaligned, the choke plate may bind slightly in the air horn, and since it is essentially operated by a small, rather weak spring between the choke control bracket and the arm on the choke shaft, a little bit of binding may cause it to stick closed until you push the
choke in all the way, which overrides the little spring and forces the choke plate open. Check the choke carefully to make sure it isn't sticking. If it's working properly, you should be able to start the engine with the choke, then back it off a bit, say to the halfway position for a moment or two,
at which time the spring should allow the airflow to partially open the choke plate. Once warmed up, you push the choke in all the way, which forces the choke plate all the way open. If the plate is binding, it may need to be realigned. Some people install them crooked during an overhaul.

2) There is also a small spring-loaded relief valve plate on the choke plate itself. This must be operational, or else you WILL flood the engine when using full choke. This valve is designed to limit the maximum vacuum that the choke can apply to the main fuel nozzle in the venturi. If you apply
full choke and this little valve is stuck closed, there will be so much vacuum that way too much fuel will be sucked through the main nozzle, flooding the engine. Remember that the fuel bowl is vented outside of (above) the choked area, so closing the choke all the way basically allows full manifold
vacuum to be applied to the fuel nozzle relative to ambient pressure in the fuel bowl. If the valve is stuck, it will suck the bowl dry in seconds.

There is also choke "technique." Generally, as soon as the engine starts, it is a good idea to at least partially back off the choke. Also, in warmer weather, you may need very little choke and only for a short period of time. Minimal choking is generally the best technique.

Anyway, that may give you a few ideas. If you have any more details, let us know.

Alan

Henry J. Fackovec wrote:

> I have a 52 M-37 which is consistently difficult to start. I turn on the ign switch, close the choke, pump the gas a couple of times, and crank, it generally does not start. I usually have to open the choke, and floor the gas for it to start. This problem is winter and summer, wet or dry, etc...
>

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