Paul_G
Well-Known Member
- Local time
- 3:53 PM
- Joined
- Dec 24, 2013
- Messages
- 2,098
- Reaction score
- 3,364
- Location
- Surprise, Arizona
I bought a used Proform 750 double pumper with electric choke on CL. The seller said they could not get it to work right on a 350 chev, thought it might be too big, put a smaller carb on the 350 and it worked well.
I took the carb apart, cleaned it up, flushed out the ports and passages, had to replace the primary accelerator pump diaghram, and put some new gaskets. Should work good right, but not. It is going on the my 73 Charger with a 68 383, 4speed manual trans.
It would idle, but it would stumble and backfire out the carb almost every time the throttle was blipped. Same thing when trying to drive it on the road. I found that as soon as the squirter shot ended the carb went lean, off the scale lean, and would backfire. Did it on the primary side and the secondary side. I put a primary metering block from a Holley 750 on the proform and tried it. No backfire, not super lean. Problems were gone.
Disasembled the carb again, took a good look at the transition circuit passages. They looked real nice, clean and not obstructed. The only thing I saw was a slight mismatch obstruction where the transition port opening in the gasket aligned with the metering block.
Called Proform, talked to Dennis, explained the issue, and that trying another metering block from a holley 750 did not have any issues. He said to send back the metering blocks and he would send me new ones. Got the new ones, put the carb back together and it runs great.
Very happy with Proform.
I took the carb apart, cleaned it up, flushed out the ports and passages, had to replace the primary accelerator pump diaghram, and put some new gaskets. Should work good right, but not. It is going on the my 73 Charger with a 68 383, 4speed manual trans.
It would idle, but it would stumble and backfire out the carb almost every time the throttle was blipped. Same thing when trying to drive it on the road. I found that as soon as the squirter shot ended the carb went lean, off the scale lean, and would backfire. Did it on the primary side and the secondary side. I put a primary metering block from a Holley 750 on the proform and tried it. No backfire, not super lean. Problems were gone.
Disasembled the carb again, took a good look at the transition circuit passages. They looked real nice, clean and not obstructed. The only thing I saw was a slight mismatch obstruction where the transition port opening in the gasket aligned with the metering block.
Called Proform, talked to Dennis, explained the issue, and that trying another metering block from a holley 750 did not have any issues. He said to send back the metering blocks and he would send me new ones. Got the new ones, put the carb back together and it runs great.
Very happy with Proform.
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