Carb Help Please
 

I just switched to gas from Methanol I put a 1150 Dom on my 438 SBC 750HP, My problem is starts great, idles great, no stumble not under load very crisp, when I set the transbrake and mat it, it stumbles and dies. Carb has 42 squirters, 96 jets square I am no carb expert so looking for some help ran injection for the last 10 years. Thanks for any help.

Re: Carb Help Please
 

Bigger squirters

Re: Carb Help Please
 

First of all, what kind of fuel delevery system are you using ? What i found was it takes a lot more volume to run methanol . Pressure is not as important as volume. I needed a #10 line feeding a bolaws fuel log. Sounds like your running out on the hit. NO VOLUME. Hope this helps. :)

Re: Carb Help Please
 

start with raising the float level about as high as it will take without running out of the boosters (after setting the fuel pressure to no more than 6 lbs.) and also fatten up the idle circuit. Make sure the primary blades are not exposing the transfer slots, if so, open the secondary blades to facilitate closing the primary blades a bit. Confused? Don't be. It's not that hard. Holler if you need help. Phil

Re: Carb Help Please
 

The three most important things about an off-idle stumble.
1. Big Squirters
2. Bigger Squirters
3. Even bigger squirters on alcohol.

Re: Carb Help Please
 

Unfortunately you probably have too big of carb for your application. A 1050 or maybe even a little smaller carb would be a much better choice. Carbs siphon fuel based on a change in atmospheric pressure. When you snap the throttle quickly, the air rushes in to equalize pressure from the low pressure inside(vacuum). Since fuel is heavier it takes longer to get there. The purpose of the accelerator pump is to mechanically squirt fuel until the siphon feed can get started. Increasing the squirter size may help, also check your pump arms and make sure they don't have excess play or need adjusting. Even with this, you may still need to downsize to increase the draw on the circuits in the carb.

I did the same thing with a 1250 on a big block in super comp. When I snap throttle it would bog or die, but if you could keep it running it would fly. Also, when I would enter the water box and just give it a hit to turn the tires slightly before doing the burnout, it wasn;t punchy. Much better with 1050 back on.

Good Luck.

Re: Carb Help Please
 

I would agree with the above replies,however I don't think an 1150 is too big.I run one on my 358. It's probably too lean on the idle circuit ,the jetting sounds odd(hopefully it has holes above the jets w/#96) and 42 squirters are too small. KB

Re: Carb Help Please
 

Carb too big.

Re: Carb Help Please
 

X2 on to big
I only use 4150 carb on a smallblock, bracket motor. If you were running B/ED thats a different story.

Re: Carb Help Please
 

He's switched from alcohol to gas,not the other way so the jets sound reasonable to me...like some others have said try larger squirters and check the throttle blade to transfer slot..thats where i would start
scott fifield