The only thing I know to help this is lower the floats. The back is as low is it will go and the front is almost the same. It's a 750 Speed Demon. On the original engine I was having similar problems but my booster was leaking causing it to kill the engine. Also when I mash the gas from a stand still it will die but is fine if I'm going about 5 MPH. I've played with the jets at the track and the best combo is 75/82. I've played with squirters too but couldn't find any difference. Right now I have 28 in front and 31 in back. Any ideas?
Car wants to die when stopping hard
- Thread starter 1969mach1351
- Start date
Ro Jo
Founding Member
Some things to try
Does your car act like it's flooded after it stalls out? If not, it sounds like a vacuum problem. If so, it could be the bowl vents sloshing fuel out. I'll continue assuming it's the vents sloshing since it is the most common problem.
A sure way to verify that the vents are sloshing fuel out is by removing your hood and air cleaner and watching the carb vents when you hit the brakes (or even scarier while you stomp the gas) - Or you could just pop the hood after it stalls and look for evidence of a lot of extra gas on the butterflies and all over the air intakes.
On a regular Holley you could run a length of hose from the front vent tube coming out of the float bowl to the aft one making an inverted U (effectively connecting the two vents) and then slice a vent hole into the top of the hose allowing it to vent. That way under hard acceleration or decel, the excess fuel would ride up the hose and not slosh into the air intakes. It looks like your carb doesn't have the same brass-colored vent tubes but maybe you might be able to adapt the idea.
Also, I recommend you check your floats to ensure they aren't leaking or "fuel-logged" causing them to float lower than they are supposed to.
If the fuel isn't at the right level with the floats adjusted all the way down and they are in good shape, you might need to do some bending on the float arms to get them into the proper adjustment range.
Does your car act like it's flooded after it stalls out? If not, it sounds like a vacuum problem. If so, it could be the bowl vents sloshing fuel out. I'll continue assuming it's the vents sloshing since it is the most common problem.
A sure way to verify that the vents are sloshing fuel out is by removing your hood and air cleaner and watching the carb vents when you hit the brakes (or even scarier while you stomp the gas) - Or you could just pop the hood after it stalls and look for evidence of a lot of extra gas on the butterflies and all over the air intakes.
On a regular Holley you could run a length of hose from the front vent tube coming out of the float bowl to the aft one making an inverted U (effectively connecting the two vents) and then slice a vent hole into the top of the hose allowing it to vent. That way under hard acceleration or decel, the excess fuel would ride up the hose and not slosh into the air intakes. It looks like your carb doesn't have the same brass-colored vent tubes but maybe you might be able to adapt the idea.
Also, I recommend you check your floats to ensure they aren't leaking or "fuel-logged" causing them to float lower than they are supposed to.
If the fuel isn't at the right level with the floats adjusted all the way down and they are in good shape, you might need to do some bending on the float arms to get them into the proper adjustment range.
jerry S
New Member
had the same problem once
after taking the car in to have the engine tuned several times, I finally switched from a carb with vacuum secondaries to one with mechanical secondaries and the problem was solved.
after taking the car in to have the engine tuned several times, I finally switched from a carb with vacuum secondaries to one with mechanical secondaries and the problem was solved.
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