View Full Version : 351 choke pull off
06-26-2013, 10:47 AM
I am having some problems with my cold start on my 89 mastercraft tristar with ford indmar 351 engine, Holley Carb. I have found out that the problem is coming from the choke pull off which doesn't seem like fonctionning right. Can anybody help me to find the part? I can't seem to find it anywhere! :( When the engine is hot, it works flawlessly. But when it is cold it starts up but doesn't idle at all and keeps shutting off. I tried ordering this part.
06-26-2013, 11:21 AM
Is the choke staying closed too long? Have you tried adjusting the choke cap leaner? There is a bi-metallic spring inside the choke cap that over time will wear out and not open at the correct rate and need replacement.
06-26-2013, 12:10 PM
I'm not sure what you mean by choke pull off.
The best thing to do is take the choke cap off, put 12V to it (using battery and test leads) and see if the coil gets hot.
If not, then integrated choke heater coil is not working correctly and the engine heat may be activating the spring enough to open it at running temperature.
When my Holley choke cap died, I ordered an OEM replacement from eBay. Verify that it truly dead first, using 12V.
06-26-2013, 12:25 PM
On a carb'd engine, you generally give the throttle 1 or 2 pumps prior to starting when cold. This pumping (or priming) will provide extra fuel for starting and allow the choke plate to shut completely when cold.
Once the engine fires up, engine vaccum is applied via a little passage to the choke "unloader" or the pull-off. This backs the choke plate open just a hair so the engine does not flood with gas completely. The pull-off is integral to the choke body assembly. It is adjusted by removing the electric choke coil assembly and adjusting the plate gap when activated. The electric choke coil is supplied battery voltage when running and will heat up and open the choke the rest of the way.
So to anwer your initial question, the choke pull-off is built into the choke body assembly. Remove the choke coil and you will then see it.
Why is is not working is the next question. It may be plugged and not getting vaccume. It may need adjusting. Next is up to you.
06-26-2013, 04:00 PM
I may be misunderstanding your issue, but to my knowledge marine carburetors do not include a fast idle cam that will keep it running at an elevated rpm until it is thoroughly warmed up. You have to do that manually by 'giving it some throttle' with the transmission disengaged (button pulled out below throttle lever).
06-26-2013, 04:47 PM