Need advise designing a part

258, Carter YF 1 barrel, and the dreaded headers. The choke is the type that is warmed by what looks to be a tube about 1/4" dia, attached to the choke part of the carb with a flare fitting. You can seed it crimped off in the attached pic. I would assume that the little tube originally attached to a device of some kind to provide it with hot air, air traveled up tube, warmed choke, choke opens. There is no provision for any electric hookup to the choke at all, so I figure my theory has to be close to correct. Unfortunately, whatever this device might have been, I'll never know, 'cause its long gone, along with the stock exhaust manifold. Currently, I have the choke screwed down tight wide open, as the thing is unnecessary in the summer here. But now its winter, and I think I may have devised a way to get some warm air to the choke with headers.

Remove the crimped off tube, and replace with copper tube of sufficient length to allow me to coil it around a header pipe or two. I figure leaving the end of the tube open, and having it be at the lowest point, would allow the warm air in the tube to be drawn upwards to the choke.

Of course, this could be total idiocy. Or a reinvention of the wheel. Has anybody else had to solve this problem? Might there be just the part I need in the help section of my FAPS? Any input really appreciated. Right now I've gotta sit there for 15 minutes warming the thing up before I can drive it. Not only a PITA, but getting expensive....

 

what about a manual choke?

 

You've got the theory of operation right. There was a choke stove in the original manual that the tube went into, and that provided the hot air.

Dorman-Motormite sells a kit to fix a thermal choke under the HELP! line. Looks to be a roll of copper tubing, a wad of glass wool, and plate with clamp to hold the end of the tube to the exhaust manifold. The glass wool will filter the air pulled into the choke cover. You should be able to make something similar.

 

X2
Works every time, easy to put in, and cheap.

Plus if you close it, the jeep wont start, most young thiefs would never know what it was.

 

X3. I go manual choke on all my carbureted vehicles. Wouldn't have it any other way.

 

Fuel Injection. :driving:

 

That's the route I went and would never go back. Turn the key, she fires right up and idles great. Throttle response and power is unbelievable.

High5

 

I'm with you guys on the FI. Even my Harley is injected. Best Harley I ever owned. Just runs, every time, like a Honda.

The Jeep is more fun than the Harley BECAUSE its not as reliable, I've gotta mess with it to keep her running her best. It's not my daily driver, its a toy.

I'm gonna give my little choke device a shot, it should work to some extent, at the least.

I'm thinking the hard part here will be to "tune" the thing so that the choke opens at the appropriate time. In other words, too much heat reaching the choke too soon = choke opening when the engine is not up to temp. Or the other way 'round. You get the idea, I hope.
I'd never thought of sticking a little air cleaner on the end. Good idea, easy to do.

If it turns out to be a completely worthless idea, it should take about 5 minutes to convert to manual.

Thanks for the input everybody. I'll let ya all know how it turns out...

 

Quick update. Works like a champ. Turns out there was no need to coil around the header tubes. Just stuck the open end of the tube down in the thickest part of the nest of snakes, tied it off to the headers in a couple of places with wire. Decided to forgo the little air cleaner, didn't see much use for it. Time will tell, I can always add one if a problem develops.
Extra Happy Bonus Points: Blower motor had quit. Turns out to be just a bad ground.
Now we can do some snow wheelin'. All we need is some snow.

 

Re the filter, there is a vacuum in the choke cover, and it comes from the engine vacuum. (If it's like the 2100), there's a small orifice in the carb body that restricts the air flow, but it does go into the engine.

Theoretically, you could draw dirty water or dust into the engine through the hot air tube... the 304 uses filtered air from the air cleaner, but I think the 258 just has a pocket in the manifold that the heater tube loosely fits in. Realistically, how likely is it that you'll get dirt in the engine through the choke stove? Mmm, don't know.

 

I'm going to keep my eyes open for a 258 with the stock setup. I'll be curious to see if it uses filtered air. If it does, I will rig one up.

Anybody have a 258 with the stock ex manifold W/YF 1bl? If somebody gets the chance to look at the stock setup and post if it uses a filter on the open end, I'd appreciate it.

In any event, when I installed the new tube, I used a piece of clear tubing to join the upper and lower tube. Sits just below the air cleaner, so I can check it without having to remove air filter assy. You can bet if I start to see that clear tube dirty up, filter time.

 

I'm on the road so I don't have a perfect shot of the heater tube on my carb.
You can kind of make it out.
Its here if it helps.

Sounds like you have it handled for now.

<Note>I took these about a 1.5 years ago right before I rebuilt the carb, hence the loose nuts and such</Note>

 

I recomend following Tims' advice and put a filter on the end of the tube.Even if you dont take it in the mud there are little insects called "mud dawbers"( at least they are here in Mi.) that seem to fill any 1/4 " size hole with a mud nest. Seems simple enough to prevent with glass wool or maybe even a small piece of stainless or brass screen( think faucet aerator screen parts) held on with a mini clamp or rolled and put into the end and then slightly pinch the tube. Just my .02 cents, sure would be a bummer getting debris up into your custom mfg. part and possibly into the carb now that you got it working the way you want it to.

 

We got snow! Probably a foot and a half above 7,000 ft. here at North Lake Tahoe.

 

Brian, yours looks just like the one I replaced, only mine had no insulation, Just a curved tube with the end smashed closed. This is the part I replaced, as that little curved thing had no detectable effect on the choke.

Yep, forgot all about the mud daubers. Good point, something will be rigged up as a filter.

Got my snow. Just a dustin at 4k Thats ok,. I like mud, too.

 

Yeah, those mud daubers are all over the place, when I bought my Jeep, the wheels were off. Every one of the chrome lug nuts had a mud dauber nest in it.

I didn't clean the choke assembly when I did it (Shame on me), and it still doesn't run well when its cold. My plan is to replace it with a MC 2100 this spring when I have time.
I just need to find one at a junk yard and rebuild it.