'76 CJ-7 304 carb issue?

Archdukeferdinand

Well-Known Member
Joined
Dec 27, 2006
Location
Vilas, NC
Holley 2bbl. Had a severely loping idle and hesitation/serious lack of power about 3/4 into the throttle. Seems like it's got either a vacuum leak or maybe a choke issue? Maybe both? PO left the vacuum system a little other than stock.

Spent today working on it, fuel, spark and air are all check. Can get some of the lope out of the idle with the adjust screw but that just masks the problem, the hesitation is still there.

The PCV was a little clogged, so that got cleaned. Then swapped a piece of tube for the fuel filter and verified that fuel was being pumped past that. Took the air injection system out of the equation, PO removed the charcoal can. Took off most vacuum hoses and they don't seem cracked, replaced them... It was running better but still hesitation and seeming to need way too much throttle for a given amount of power.

Seems like the choke is also a problem but separately from this, the choke linkages seem kinda gunked up and it doesn't close the blade when the motor's cold.

Dizzy, plugs, wires, fuel filter, all new recently. Beginning to think a carb rebuild is next. Any info or tips would be greatly appreciated.
 
Are you certain on the Holley? It's not an MC2100 like would have come on it from the factory?

First thing. Wiggle the throttle plate shaft. If it has play in it, you'll have a leak there. If you do, throw the carb away and go find another.

Idle screws will only make a difference on idle. Nothing to do with 3/4 throttle issues.

If your choke plate is not closing all the way when cold then yes clean it all and make sure it closes. Is it manual or electric?

Replay all rubber hoses and vacuum port plugs. Make sure all vacuum ports got to a hose or are plugged off.

Take some carb cleaner and speak the thick gasket at the base and listen for rpm changes. If it goes up, then there's a leak at the base.

Are you still runnin points ignition? If so, check your points are adjusted correctly. This often feels like a carb issue. If you can, ditch the points dizzy and go electronic.

Let us know on that stuff an well go from there.
 
If it is a Holley, throw it as far into the woods as you can. Then get a 2100 motorcraft carb, install and forget about having carb troubles. After 25 years of trying to keep Holleys running right, this is the best advice I can come up with.:D
 
mbalbritton said:
Are you certain on the Holley? It's not an MC2100 like would have come on it from the factory?

First thing.
Click to expand...

Holley 64-5175, Installed by PO. Choke is the type that uses manifold heat to open/close. Good call on the points, I'll check those and thanks a bunch for the other info. I'm still hoping to find a magic bullet vacuum leak.
 
then I agree with Tom. Throw that carb as far away from the jeep as possible. Better yet, box it up and ship it to Nepal. Then go to the junk yard and find an MC2100 for $20, check the throttle plate counter shaft for play. and get a rebuild kit for $30. Stoooopid simple carb to rebuild.
 
Another good reason to kill all the "extra" lines and go motorcraft with a single fuel line and a single vac line to the dizzy.
 
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