FMC400 wrote a very helpful thread titled choke questions answered. In it he asked that if someone had specific questions they start a new thread. I think the old one might be a sticky......

Anyway, on page 4 of that thread someone wrote this:

The factory electric assist will not kick in until the hot-air stove brings the heating element to a certain temperature.


I have an 81 351M and it has the factory electric assist, so as I'm learning about the choke/vacuum/carb mess that hauls my trash and firewood, I was hoping to get a little further in depth since I'm not making the connection in my head.

I actually did a really good job rebuilding my first 2150. After catching it on fire a couple times, I learned the importance of hooking up all the vac lines correctly - I still have the diagram on the core support and even though it was scary at first, I dove in and was able to reattach everything like it was at the factory. So I think that I have an intermediate understanding of how most of the systems are supposed to work.

But I have to ask you guys to dumb it down for me I guess: what does that line that I copy/pasted above mean? What does it look like on the other side of that male connector? Does it connect right to the bimettalic coil and juice runs through the coil like a strip heater or toaster? And if so, why does it only kick in after a certain point?

 

Here's what Ford's 1981 shop manual says for the Motorcraft 2150 carb you have on your truck:



And, for completeness on chokes, here's an excerpt from Ford's 1981 Electrical and Vacuum Troubleshooting Manual regarding the all-electric choke as opposed to your electric-assist version. And, by the way, you can find that on Page 27 of the EVTM on my web site here: Start, Ignition, & Carb Circuits - Gary's Garagemahal.

 

wow - thanks!

I'll check it out tomorrow. Just to clarify, I (surprisingly, since it was the first 2 barrel I ever rebuilt) did a pretty good job on the carb rebuild, but even though I took photos and notes, I panicked when I was hooking up the vac lines and ended up with 4 open vac ports. So that's where the flames came from. Once I manned up and forced myself to replicate the vac diagram, it ran much better.

But to be totally honest, I didn't know squat about chokes and I finally admitted it and now I'm in the process of trying to get the choke system(s) working the way they should, and not "almost good enough".

The only other complaint I have about my truck currently is that when I replaced the exhaust manifold gaskets, the new gaskets pushed the side to side diameter just enough fractions of an inch (I refuse to use the metric system) so now the y pipe won't quite match up. So I used about a full tube of exhaust goo and got the exhaust leak down to a manageable level. I am now mulling over whether to take the y pipe off and bend it out enough to get a better seal onto the manifold nubs, or whether just to spend the money on a set of new duals. What do you think?

 

I'll try to remember to take a pic of the other part of the same page in the shop manual as it explains how to adjust the choke.

On the exhaust, if your M is stock you won't be able to wind it up enough to need dual exhaust due to the low compression. So, I would try to bend the y-pipe. But, duals sound good when you use something like Magnaflow mufflers, so go that way if you want the sound.

 

Thanks, I'm a cheapskate so I'll just try to muscle the y pipe.

And I'm about 2 chapters in to your magnum opus. Very helpful so far!

 

Yeah, I like Jeff's (fmc's) thread, he's a really helpful guy over in the 73-79 forum.

We have some pretty decent choke stuff in our sticky:

https://www.ford-trucks.com/forums/8...ml#post7434602

 

Not to hi-jack the thread but the electric only choke it said it has two pills one that works all the time and the other that starts working above a certain temp to speed up the choke operation.


I wanted to ask where would one get this choke cap? Secondly can it be retrofitted to a heat with electric choke carb? Mine the tube broke in the exhaust manifold and only option I thought of is coiling a piece of tubing around the exhaust manifold to fix it but think it would look tacky.

 

I believe the Holley 4180 has the all-electric choke stove, and the were used on the 351HO and the 460. I have one and might get a chance to check that tomorrow, but maybe someone else can confirm that. Also, Jegs has kits to convert hot-air chokes to full electric: Holley Electric Choke Parts & Conversion Kits | Holley. Not sure, but I think the Holley parts will fit the Motorcraft carbs.

 

I think Dorman sells kits with flexible tubing intended to replace those which have rusted/broken off... but it would be a LOT easier to implement if you first remove the manifold and do the work on a bench.

 

Why don't we ask one of the other Jedi Masters @85lebaront2? Somebody with a less-severe memory problem....

 

It would be easier on a bench. But if I pull the manifolds off I might as well order a set of headers and now the choke tube is a moot point.


Mine just went into the manifold and that was it after it broke I threaded a screw into the tube and tried with vice grips to pull it out did nothing but break the screw off in the manifold. So bench would be best but I at this point with work and everything going on right now don't have the time to fight with this.


This is probably why with cold weather the thing wants to stay up on a 2,000 rpm high idle for so long. Also been meaning to check he choke pull off to see if it needs to be adjusted as it should go to 2,000 rpm high idle and a tap of the throttle it should idle down to the standard 1,500 rpm idle

 

Request sent.

 

Classic definition of scope creep.... no! no! no! Your focus needs more focus!

Besides, you'd also have to reroute/rebend the exhaust pipes to meet up with the headers, and then there are all the problems people have with headers e.g. hitting or being real close to the starter motor, etc.

 

Said by the King of scope creep. Just belts and hoses - right.

 

Yeah.... I gave thing back to him (finally!) just last Sunday....