Engine stall on hard braking (demon carb)- HELP

[DAVID GAGNARD]

Originally Posted by Grubby

I just got off the phone with a Demon Tech Rep. We talked about float level. I have tried several settings ranging from bottom of the glass to top on both the front and back. It is currently set with 2/3 on the front bowl and 1/4 on the rear.

The suggestion is to advance my base timing from 12 deg to 16-18 deg. I will try this tonight and post the results. I am concerned about detonation and will watch for it.

I liked the suggestion about backing the idle mixture screws out 1/8 turn. If the timing does not fix my problem; that is next.

This thread is interesting.

John

I don't see how the timing has anything to do with it...It has to be a fuel issue. Under hard braking the fuel will slosh to the front of the carb, front/primary bowl will be away from the jets, rear/secondary bowl will be to the jets.....
Between that and vacum or lack of vacum, is where I think the problem lies... As said earlier, my 25 year old Holley DP almost never does this.........has to be in the design of the carb......

My front float is about middle of the sight glass and rear float is about 3/4 of the sight glass, I've not noticed any difference with different float setting.......

Be careful when advancing your timing, mine is set at 10 degrees intial and 32 degrees total, as I found out on the engine dyno and chasis dyno, any more on my engine and I'll probably destroy it to engine knock.......adding from 4 to 6 degrees more of timing can and will destroy a motor in seconds,depending on how much timing your motor needs. I've seen the dyno results and "most" small block Fords including strokers usually do the best with no more than 30 to 32 degrees total timing..My 331 did the best at 32 degrees, we tried adding 2 degrees at a time and found for every 2 degrees added, the motor lost from 8 to 12 hp and torque!!!!!!!!!!!!

David