304 skipping

allx3hers05

New Member
Joined
Apr 23, 2009
Location
Four Oaks
i just put a 79' 304 in my cj7.... engine is orginal except for and HEI distr. .... i have drove it for about 4 months ... ran fine as can be... went to the beach and back it ran so good.... today i was cruising around 50- 55 mph and then it started lightly skipping..... my first thought was that is was out of gas..... but it kept running then i started playing with it.... with low rpms it lightly skipps but when i accerate quickly the skipping gets more stronger... idling it dont skipp..and when its in neutral and i get on the throttle it doesn't skipp..... just started skipping out of the blue......

curious if anybody has had this problem..... what to check first .... plugs and wires?(which are currently orginall i belive)..... vacum? .......tranny?
thanks
 
Id start with the fuel system, specifically filters and air leaks
 
that makes alot of sense now that u said that cause i just started hearing air being sucked from around the fuel pump i didn't even think about that
 
*IF* it's the stock MC2100...
- the idle circuit in "in control" until 800-1000rpms
- at that point the idle circuit hands off to the main circuit, the fuel being metered by the jets

Pull the top off the carb (FWIW, with a little caution it *can* be run the top off if you hold your hand over the float, otherwise the fuel pressure will push the float/needle out and spray fuel everywhere). *IF* you have ample fuel in the bowl, check the bowl for trash & specifically over one/both jets. Since the intake feeds only 2 cylinders per side, 1 jet being blocked/partially blocked will make it run like @$$ and mimic an ignition problem (popping, low power, etc).

If you find junk in the bowl (high likely you will!), pull the float/needle, cover the bore (to keep unwanted junk from falling into the intake), and blow it all clean with compressed air. If no compressed air, yank the linkage, fuel lines, choke vac pipe, & 4 nuts holding the carb. You'll be able to dismantle the entire carb in a few minutes, but pay close attention to how it came apart to insure you put everything back in the same order (watch for the ball under the idle tree!). After a few tries, you'll have the entire process down to 10-15 minutes

At this point for S&G's, double check the wires to insure they're seated properly on BOTH ends, looking for breaks (appear as black/gray tracks on the sheath). Also, check the cap & the rotor base for cracks & burnt terminals... unlikely, but I had a rotor crack once that took a while to find.
 
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