Re: Marvel Carb Specifications

Tom Goodman wrote:

> Geoff, a few days ago, you posted something to the effect that you had checked in

> your Marvel carburetor book regarding altitude performance of the ubiquitous Marvel

> carburetor and it suggested fitting leaner jets for prolonged use above 4,000 feet.

> Having never seen a Marvel carburetor book, I am intriqued by this and would like to

> find out more since I live, work, drive and sleep for most of the week at 6100 feet or

> so and I note that the exhaust from my '28 Super Six Hudson smells somewhat rich.

> My carb is, by the way, an "E" and, as you pointed out, it is likely attached to a '29

> engine.


> If it is not too much of an imposition, would it be possible to obtain xerographic copies

> of the applicable pages of your book, either from you or from anywhere else that you

> might recommend. I do not seem to be able to get much from the club librarian, having

> yet to receive the promised "list of publications". Of course, I am accustomed to paying

> for that which I receive.


> Thanks for your kind advice and counsel. Please respond to either my "official" one-list

> address of or this address (my work address).


> Thanks and Regards,


> Tom Goodman

Tom, I am happy to send you the photocopy of the Marvel book, but it may

not do you much good, as parts of course are unobtainable. What I

suggest you do is lean the Jets down a little at a time and see how you

go. This is quite easily done. The jets unscrew from the tube, and

you can then tin the outside of them, and solder a length of 5 amp fuse

wire to the side, and insert down into the jet. If the car still

performs okay, then try it with a 10 amp fuse wire. I did this to a

'29 earlier this year, and improved the fuel economy from 12 to 16

m.p.g. Performance was unaltered. It would pay to get the exhaust

gas analysed to check the richness of the mixture if you were in any

doubt. Also it pays to lower the float level somewhat by bending the

lever on the float, as the fuel today is lower specific gravity than the

old 65 octane which was used in 1929. Measure the distance from the

top of the bowl to the low speed jet orifice, and the distance to the

top of the fuel in the bowl, and adjust the float level so it is 1/8"

lower than the top of the Jet. It also pays to seat the needle valve

with a mild abrasive, such as silver polish. Good luck,

Geoff Clark.
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