Tillitson vs. Zenith

[Mort]

The post about most "frequently asked questions" prompted this one. One of those questions is why does a model A stall when it comes to a stop. Is there any difference with that problem between a Tillitson vs a Zenith carb. IE. is one of those carbs more prone to the stalling problem than the other??

 

[mrtexas]

Never had that problem with a Tilly. I've had it with a Zenith though.

 

[steve s]

The conventional wisdom is that the gasoline in the float bowl moves to the front during a hard stop, lowering the level at the outlets end of the bowl, effectively starving the motor for gasoline.

I've also read the opposite: namely, the problem occurs when the gas sloshes back to the outlets end of the bowl, flooding the motor. A variation on this is that the slosh allows the float to drop, over filling the bowl and flooding the motor.

Later carbs added baffles and had the float crosswise to reduce this problem, but then you're asking for trouble going around corners.

I don't know what to believe, but enriching or leaning your baseline settings should tell the tale. I do know that my new Zenith (sometimes disparaged as the "forklift carb") is much more resistant to the problem. Literature says its float setup was designed to accomodate use on very steep grades.

Steve

 

[Ron in Quincy]

Its usually caused by the float level setting and the size of the idle jet opening.

Ron

 

[MrTube]

I haven't had this problem with the Zenith yet.

I did have it with a 1980s quadrajet while doing donuts though. came to a sudden sideways stop and it stalled.

 

[Dick Deegan]

Ditto

 

[MrTube]

I came to a sudden stop doing this very same thing with a '68 Mercury Cougar. The thing that stopped me was an Illinois State Trooper I didn't see coming!

Did it stall?

 

[Frank Nemo]

My Tillitson has never given me any kind of stalling problems.

 

[Kirby1374]

Did it stall?

I bet he did in answering the officers questions

 

[MrTube]

I bet he did in answering the officers questions

Too bad it wasn't a Toyota.. He would've had an excuse then.

 

[30ccpickup]

I agree with Steve's conventional wisdom, that the gasoline in the float bowl moves to the front during a hard stop, lowering the level of gas, preventing the fuel to flow through the Compensator Jet, thus starving the Secondary Well, which prevents fuel to flow through the Idle Jet. The solution is to change the float level to allow the bowl to have more fuel.

 

[MrTube]

I agree with Steve's conventional wisdom, that the gasoline in the float bowl moves to the front during a hard stop, lowering the level of gas, preventing the fuel to flow through the Compensator Jet, thus starving the Secondary Well, which prevents fuel to flow through the Idle Jet. The solution is to change the float level to allow the bowl to have more fuel.

This will cause it to run richer, will only aggravate the problem caused by running an air cleaner.

 

[TomW]

My stalling problem stopped after lowering the fuel level. It was only a tiny bit higher than spec.

 

[steve s]

I agree with Steve's conventional wisdom, that the gasoline in the float bowl moves to the front during a hard stop, lowering the level of gas, preventing the fuel to flow through the Compensator Jet, thus starving the Secondary Well, which prevents fuel to flow through the Idle Jet. The solution is to change the float level to allow the bowl to have more fuel.

One of the problems I have with Steve's conventional wisdom is that normally a too-lean mixture is associated with backfiring, but I've never heard of backfiring during the hard-stop stalling process.

Steve