choke not opening to 90 degrees when warm

[72CampSpecial]

Can anyone identify this choke?? two wires going to it..when i bought the truck a few months ago it was opening the choke flap to 90, but post rebuild of the Carb it doesn't seem to be opening past 45. So either ive got something hooked up wrong, or the electric choke isnt working properly..

When the flap is at 45 degrees i can freely move the choke, and i can feel some spring tension against it.

Is there a way to test the electric choke?

Could the spring be wore out?

[70chev383]

Typically electric cokes work off of engine temp and are tied to the thermostat
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[72CampSpecial]

70chev383, thanks-- yes, and I'm not sure that my thermostat is working.. how do i test it/verify that it is operating? I tried using my multimeter, but im not sure what voltage i should be looking for.

[72CampSpecial]

and let me re-phrase my question.. can anyone ID this Choke Thermostat? everything ive found online only has one wire to it.. mine has two?? and its a Rochester Quadrajet 77 Cali emissions carb

[GASoline71]

That choke uses a coil in it that is heated up with a 12v source. It does not run off the thermostat. One wire is the 12v, and the other is ground. See if you have a good ground and 12v at the hot wire.

Its also adjustable by loosening the 3 small screws on the perimeter, then turning the black housing to adjust. Turning the housing to adjust will take the slop out of it so the choke butterfly will be vertical when open. There should be a small "pointer" on the black housing that will correspond with the marks on the metal perimeter.

Gary

[rsavage]

To adjust the electric choke, take the Air Cleaner assembly off so you can see the choke plate (engine should be cold and off), loosen the three screws on the choke coil. and rotate the coil until the choke plate just closes and then turn it just a tiny bit more. You should have someone holding the throttle just slightly open while doing this. If your choke coil has 12v to the terminal with the wire with the red spade on it with the key on, and you have a good ground on the other, the coil, if good, should allow the choke to fully open.

[68gmsee]

Yes, 12vdc is what you should have to the coil. The other wire may be a ground but usually they're internally grounded to the carb frame and engine block through the bolts, etc. Some of these trucks have been rewired and changed by previous owners so no telling where the wires go to unless you follow them out.

If you meter between ground and the main wire you should have 12vdc when either the key is on or the engine running depending on how it was hooked up.

You may also have a defective or basically worn out bimetal coil in the thermostat housing. I have the same carb and the t-stat went out on it. Just won't open up enough. I removed it and used a hair dryer to test it. I'm in the process of ordering one from either the net or NAPA.

[72CampSpecial]

Originally Posted by 68gmsee

Yes, 12vdc is what you should have to the coil. The other wire may be a ground but usually they're internally grounded to the carb frame and engine block through the bolts, etc. Some of these trucks have been rewired and changed by previous owners so no telling where the wires go to unless you follow them out.

If you meter between ground and the main wire you should have 12vdc when either the key is on or the engine running depending on how it was hooked up.

You may also have a defective or basically worn out bimetal coil in the thermostat housing. I have the same carb and the t-stat went out on it. Just won't open up enough. I removed it and used a hair dryer to test it. I'm in the process of ordering one from either the net or NAPA.

68mgsee... thanks, any idea what that part # is for the thermo housing/bimetal coil. I went to O'Rylies the other day and we couldnt find one with 2 wires..

--Everyone else.. thanks for hte input.. really want to get this running right. I installed Cliff Ruggles carb kit, and that helped.. but now ive got the choke issue holding me back!

[68gmsee]

Originally Posted by 72CampSpecial

68mgsee... thanks, any idea what that part # is for the thermo housing/bimetal coil. I went to O'Rylies the other day and we couldnt find one with 2 wires....!

I haven't been to NAPA yet but will later this morning. I looked online and found they'll probably have to order it.

Mine is a single wire choke which is grounded through the carb itself. Stock choke thermostats are single wire and more than likely you can ditch the second wire on yours. Just use the main connector which is the one in the housing.

To double check, place a volt meter on DC volts. Disconnect the t-stat wires and check the voltage on the main wire to ground. You should have 12vdc with either the key on or engine running depending on how it's wired.

Place the meter on ohms reading and check the other cable to engine ground, it should read zero or close to it. You don't need this one for the single wire t-stats.

[72CampSpecial]

Originally Posted by 68gmsee

I haven't been to NAPA yet but will later this morning. I looked online and found they'll probably have to order it.

Mine is a single wire choke which is grounded through the carb itself. Stock choke thermostats are single wire and more than likely you can ditch the second wire on yours. Just use the main connector which is the one in the housing.

To double check, place a volt meter on DC volts. Disconnect the t-stat wires and check the voltage on the main wire to ground. You should have 12vdc with either the key on or engine running depending on how it's wired.

Place the meter on ohms reading and check the other cable to engine ground, it should read zero or close to it. You don't need this one for the single wire t-stats.

68GMSEE...
here is the part # at NAPA: Part Number: CRB 21620
http://www.napaonline.com/ShoppingCa...ping-cart.aspx

i have to order one and wait a week for it to come in.. grrrr....

[72CampSpecial]

Originally Posted by 68gmsee

I haven't been to NAPA yet but will later this morning. I looked online and found they'll probably have to order it.

Mine is a single wire choke which is grounded through the carb itself. Stock choke thermostats are single wire and more than likely you can ditch the second wire on yours. Just use the main connector which is the one in the housing.

To double check, place a volt meter on DC volts. Disconnect the t-stat wires and check the voltage on the main wire to ground. You should have 12vdc with either the key on or engine running depending on how it's wired.

Place the meter on ohms reading and check the other cable to engine ground, it should read zero or close to it. You don't need this one for the single wire t-stats.

Any idea which single wire T-Stat would work in place of the 2 wire one?

[68gmsee]

Originally Posted by 72CampSpecial

Any idea which single wire T-Stat would work in place of the 2 wire one?

I decided to order one from Autozone kit since it was the single wire with the cable and looked more like what I have now-pn 1932. It will get here tomorrow afternoon and I'll let you know how it works out.

btw: I have mine connected to the 12 volts source of the alternator so that it gets power when engine starts. Other sources are the coil if engine has one, starter solenoid to key on 12vdc or oil pressure switch on some newer engines.

http://www.autozone.com/autozone/cat...dm/1932/image/

[72CampSpecial]

Originally Posted by 68gmsee

I decided to order one from Autozone kit since it was the single wire with the cable and looked more like what I have now-pn 1932. It will get here tomorrow afternoon and I'll let you know how it works out.

btw: I have mine connected to the 12 volts source of the alternator so that it gets power when engine starts. Other sources are the coil if engine has one, starter solenoid to key on 12vdc or oil pressure switch on some newer engines.

http://www.autozone.com/autozone/cat...dm/1932/image/

Found it on their site.. thanks..

[68gmsee]

Got the Edelbrock made choke t-stat from Autozone (pn1932) and fits perfectly on the choke housing. It comes with the cable with locking type connector to keep the wire from accidentally disconnecting with engine vibration and causing a direct short to ground.

I tested the t-stat by jumpering the connector to batt+ and touching the housing to batt- terminal and worked great. I'll finish installing as soon as weather permits.

Only thing that stumps me is the cost... Expensive little bugger.

[72CampSpecial]

Anyone one know what is different about these?? other than price..
The first one is what my truck "Calls for", the second one says 2bbl or 4bbl.. and is HALF the price.. the other 2 are just cheaper and are comparison..

the only thing that I can see different from the first one and second is R-2 vrs R-4??

http://www.napaonline.com/Catalog/Ca...620_0177792044

http://www.napaonline.com/Catalog/Ca...666_0177791867

http://www.napaonline.com/Catalog/Ca...678_0177792182

http://www.napaonline.com/Catalog/Ca...658_0177793678

[68gmsee]

FYI: Got the choke fixed on the test stand engine with the new thermostat housing from Autozone pn 1932. Opens up like it should now. Old one was not opening up at all even when I put a hair dryer to it. I suspect the bi-metal spring just got tired cause there's nothing else but a carbon contact washer and spring behind the coil.

At this time I'm using the alternator 12volt source with engine running only.

[Steeveedee]

Yeah, last time I checked the Edelbrock electric choke was about $40. As far as the old one goes, did it have a part number on it that you could trace to a known mfg? It may have failed, but maybe it was just the wrong one to start with.

And, yes, Cliff Ruggles knows his Q-Jets, no doubt there.

[72CampSpecial]

thanks for all the help everyone.. i called and spoke with Cliff R today and ordered a new electric choke and some other parts from him.... looking forward to getting this truck running properly...