choke question

[79granada]

i have a 79 250 the wire for the choke was not hooked to anything what should this be hooked to? the metal tube running from the choke (roughly 1/4in) is not there where does this run to and what is the porpse of this tube?

 

[chad]

the wire goes to the stator terminal on the alternator
the tube brings warm air up from the exhaust manifold into the bimetal chamber to activate the choke.

It would B great if some 1 posted a pic for him.

 

[79granada]

thanks chad ill have to look a lil harder and see if the tube is down on the manifold i just know it wasnt hooked up to the carb picture would help too

 

[chad]

tube is down on the manifold
Yeah, it's simply (is alu) bent down there to let air just filter up, warmed. May still have some stuff wrapped around it? Cloth-like. That's asbestos, in the ol days we weren't afraid of it...
; - o

 

[79granada]

yeah i know whaat your talkin about.mine is not in plain sight if nothing else it shouldnt be hard to fabricate a new one. witch terminal is the stator?

 

[chad]

witch terminal

C the back as a clock face
battery, field, & ground R all on the right (3, 4 & 5 O'CLOCK.)

Stator is alone on the other side around 11 o'clock...

 

[79granada]

well i found the choke wire (thats the One that runs from the alternator and melted to the manifold right?) bit the tube is not there.

 

[bubba22349]

If you look at some auto parts houses they have a Dorman Help section with small parts they have a choke stove repair kit 76850 that might work or you can use a piece of brake line if you have one. They may have a plug for electrical to repair the wire too.

 

[79granada]

i can fix the wire not a big deal wondering where the tube runs to on the manifold is it the heat riser?

 

[JackFish]

Often there are two tubes going to the manifold.
One that goes to the choke comes from a replaceable fitting on the top of the manifold right dead center.
The other comes out from the bottom and goes to a port on the carb venturi. Not auite as easily fixable if you need it.

 

[79granada]

right ive got the one that goes to the carb venturi. for some reason the previous owner unhooked the choke and had it tied open with kite string. so this tube plugs into the manifold and pulls exaust gas up to the choke?

 

[bubba22349]

There is a tube inside the exhaust man. out through the bottom so it's not really suppose to pull any exhaust into the choke just the hot air

 

[79granada]

ok will look for that. what is the pourpose of that is it to pull in hot air to open the chokhe up?

 

[bubba22349]

Yes you need both electrical & heat to the chokes (bimetallic) coil spring this causes the spring tighten and fully open the carb's choke blade.

 

[chad]

there is a coiled spring (flat like a dipstick or ribbon) inside that round black plastic ("bakelite") domed thing on the back of the carb. the tube sends heat up there (a lill differently on my YF). If U look there R hash marks on the plastic that show measurements - clockwise & counter. U can adjust that by turning the plastic, but that's far down the road - after lots of other tuning steps (the last I'd say).
Good Luck, brother. Have fun, be safe AND productive.

 

[79granada]

yeah ive had to adjust them before just havent had to deal with missing parts. btw chad i have the yfa

 

[JackFish]

Often the "port/chamber" inside the exhaust manifold burns out and does let exhaust gases into those pipes. Very bad. And the tube itself corrodes away so the owners will plug the hole in the manifold with a bolt. And then the manifold will develop cracks too.

 

[chad]

chad i have the yfa
OH, that's Y the 2 tubes. Thanks for the post back.
Some have internal passageways (only) to let the hot air up/in.
Not sure I've seen the YAF. It IS for the 250 so I'd love to know more about it (goes w/the hex or lrg log head).
When you get it straitened out n have more time I'd like to know how high it is bottom of bottom flange to top of air cleaner bracket...

 

[79granada]

next time i get down to the garage ill measure that it might be a week or so i work 3rd shift so its tough but from what ive read they are the same. carter uses a 2 digit model number/letter system the 3rd letter means there was a slight revison to the design "A" would be the first revision "B" would be the second and so on. but i dont know what all the "A" revision was obviosly the hot air tube to the venturi but im not sure what else they did

 

[powerband]

The rotted off choke hot air tube and tube which passes through the exh. manifold is a common problem . A simple fix is to get a short piece of brake line which, already has the needed flare fitting for carb, and clamp along exh. manifold or pipe a few inches leaving open at the bottom providing hot air to actutate choke. I have used this method with headers.

Have Fun