Accelerator pump cam selection methanol carb

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Retroboy

Retroboy

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Hello. I bought a Methanol carb from a speedway guy. Turns out it's a home converted 850 annular discharge DP. It has 50cc pumps front and rear. I want to run it on my very light race only car. It has a horrendously heavy pull on the accelerator cable on the secondaries. Looking for why I removed the brown pump cam from the secondaries and it is way different. This cam is the most aggressive Holley list. I figure a dirt track car is on and off the throttle so needs the pump shot where my drag car doesn't and would benefit with a longer slower delivery. Anyone agree or disagree. What secondary pump cam have you used on a drag only car. It's a foot brake car leaving at about 3000 rpm by the way.
Cheers
 
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Post this in the N/A section on Yellowbullet...There are some extremely smart carb guys there....
 
the 50cc pumps should have the brown cam. set them both up for a quick shot of fuel. keep going up in nozzle size on both until it doesn't bog. don't be afraid of going too big. go up at least 2-3 sizes at a time. make sure the secondary blades aren't hitting the manifold and your throttle cable is adjusted correctly. try leaving off an idle, at 3000rpm the pump shot is used up.
 
Thanks Bob. I had a look at this carb tonight and it's all up the sh#t the way it was "set -up". It has big pumps with the crazy brown cams then to make up for it small 25 squirters. Put a fuel line and pump on it and the floats are way high so at 6 psi there is fuel dribbling through the boosters. I ran a carb in the 1980's and spent ages sorting the pumps out when I went to a converter type trans. I figured there were boats with prostock engines that left from idle so I applied a bit of that thinking and all good.
I'll spend a bit of time with this and most likely chuck the brown cams in the trash replace them with some that don't feel like they want to break my throttle cable adjusted to start their travel just on start line rpm and start with some 34 squirters. I have 24 deg at idle and an additional 10 degrees in my maggie. I was just looking for a quick bolt it on and all's good deal with this carb as it's only a short term deal but as usual I'll put in the time and get it sorted and it will just have to be a few more weeks until I'm ready to rock and roll.

 
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