Jeep engine trouble.

[Collin the Hen]

Hey, guys. I'm a new guy with a "new" 84 CJ7. Just got it a couple weeks ago. Well, anyways, it has the 258 in it which has just been remaned 15000 miles ago, but it lopes like mad at idle. When it's revved up passed 1300 rpm, it runs smoothly. It has the MC2100 on it that's been rebuilt 3 times, once including myself, and it still lopes! :x Our mechanic thinks it's too big of a carb for the 4.2, but I believe my timing may be off a hair. :?| What do you guys think?

 

[jeepster357]

Do you know if this problem has been there since the rebuild? If so then its possible the that the camshaft might not be correct for your engine. Im not a expert so I wont attempt to speak on durations of valves opening and closing etc.

Oh and by the way, welcome to Jeepz, new guy here myself but these folks do seem knowledgeable so im sure you will get some ideas quickly.

 

[elevatorman]

Hey just another new guy here. On your problem-all gasoline engines operate on the same basic principles. First check your timing!!! secondly check that all your plug wires are good as they can break down over the years and will sometimes fail at low idle yet "spark" as the RPMs increase.
If that doesn't help try looking into a smaller pilot jet for your idle circuit.
Hope this helps GOOD lUCK

 

[Collin the Hen]

thanks Randy. I got it figured out a while ago, though. It turned out to be my timing, and bad spark plugs, so your advise was very important. By the way, welcome to Jeepz!