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Old 01-04-2019, 10:10 PM   #1
RUNNERBUN
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Default Marvel schebler main jet flow rate

I have recently accuired a Marvel Schebler Carburetta which is in very nice condition. I have tested it on an engine which is on a stand and it appears to run quite nicely other than it seems to be running a bit too rich even with the GAV turned all the way in.
I would like to test the flow rate of the main jet which unfortunately appears to be interfered with (rough solder at the tip)
I am aware of the great articles written by Barner Jeff in BC but I can't find any reference to a flow rate for the main jet.
Can any one supply an acceptable flow rate for me to test and resize as required.
Thank you in advance for any advice.

A big thank you to Jeff in BC for all his great work, it was very useful.

Runnerbun
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Old 01-05-2019, 12:48 AM   #2
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Default Re: Marvel schebler main jet flow rate

I would suggest measuring it now, re solder and drill a few sizes smaller then work up.
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Old 01-05-2019, 01:32 AM   #3
RUNNERBUN
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Default Re: Marvel schebler main jet flow rate

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I would suggest measuring it now, re solder and drill a few sizes smaller then work up.
Thanks Redmodelt, that's my back up plan if I can't get an actual flow rate. Just thought I would take the easy way out first.
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Old 01-05-2019, 04:30 AM   #4
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Default Re: Marvel schebler main jet flow rate

When I got my first Model A, the PO had adjusted the flow rate of the main jet by putting about 4 strands of wire from ordinary plastic covered electrical wire. He put them through the jet and bent over the top and bottom so they wouldn't fall out. I think he did it by trial and error and he knew what he was doing. The car ran very well, had as much power as any of the other cars in the club and usually won the best economy trials.
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Old 01-05-2019, 04:49 AM   #5
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Default Re: Marvel schebler main jet flow rate

Synchro, that is definately thinking outside of the square. If all else fails I might just give it a try.
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Old 01-05-2019, 06:24 AM   #6
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Default Re: Marvel schebler main jet flow rate

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Interesting topic. Where does one get the drills small enough to drill out the jet?

I have been playing with the MS carbs, ( An addiction of sorts) All run good. Some get great mileage others get horrible.

Paul
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Old 01-05-2019, 06:39 AM   #7
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Default Re: Marvel schebler main jet flow rate

Google pin vice drill bits for some options
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Old 01-05-2019, 06:50 AM   #8
RUNNERBUN
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Default Re: Marvel schebler main jet flow rate

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Interesting topic. Where does one get the drills small enough to drill out the jet?

I have been playing with the MS carbs, ( An addiction of sorts) All run good. Some get great mileage others get horrible.

Paul
Just search Micro drill bits on Ebay. Plenty available, mostly under $4 to $5 or your nearest tool supply shop should be able to help.
You will also need a pin vise (a hand operated chuck /vise to hold your micro bits.)
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Old 01-05-2019, 07:44 AM   #9
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Default Re: Marvel schebler main jet flow rate

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Google pin vice drill bits for some options
Dan,
I have a drill set that goes down to .022"----Imagine the precise machinery that made it? I LOST it in the carpet & Buster T, my Dog, found it for me!!!
Bill W.
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Old 01-05-2019, 01:37 PM   #10
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Default Re: Marvel schebler main jet flow rate

Here is the Guru for Marvel-Shembler carbs:

JR BULLOCK
976 COUNTRY ROAD 2310
TEXARKANA, TX 75503
TEL: 903-748-8299
[email protected]

JR rebuilds and sells Marvels. Give him an call. I think he could accurately answer any questions you may have.
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