88 Ram 50 problems

Great site. Have a few questions and hope this is the right area to post in as I am new to this.
I started having carb problems with the Mikuni about 3 months ago so I purchased and installed the Weber kit about 3 months ago and all was great until about a week ago when I started to get a backfire thru the carb under load. I hadn't installed an electric pump when I did the install so I did that last weekend but my problems continue. New cap, rotor, and plugs. Timing is spot on and compression is good at around 150 on all 4. Any suggestions would be greatly appreciated! I have the G63B with 235,000 on her. No leaks and no smoke.

Do you have the MCA Jet Head? If so one could be sticking or going bad. Put in a jet valve elimination kit. There about $30.00 Other wise it could be a sticking or cracked valve. If you put a vacuum gage on it make sure the needle holds steady and not whipping back and forth.

Oh ya, welcome to the site.

Thanks for the quick reply. I do have the jet valve head. I put a vacuum gage on the intake. It flutters but only about 2 or 3 hg on the gage. I didn't think the jet valves could cause it since the ports to them are blocked by the adapter plate from the new carb. Would a leakdown test show anything? Also, any recomendation on where to get the elimination kit?

2-3 is normal. Ya I guess the Weber does block the ports, but one might have a hot spot on it. But they are all inter connected. Rockauto.com should have them. You might also have a loose connection on the ignition system. It might also be running a little to lean and need the float to come up just a touch.

Already went thru the carb and bumped up the float level. Spark tested good but I guess under load is a different story. My idle and general performance aren't as good as before either. Guess I'll try the jet valve eliminators and see what happens. I also rodded out my cat converter hoping my exaust was restricted to no avail.

How about a new fuel filter?
Is the backfire through the carb or out the exhaust?

New filter already installed. Fuel pressure check @ 3.5 psi. Backfire is out the carb. Brought home a leakdown tester from work but haven't had a chance to run the test yet. I plan to pull the jet valves tomorrow night and see what they look like before ordering the elimination kit.
I really want to thank you for your input thus far. This is the second 50 i've had in the last 15 years. Had an 84 Power Ram 5 -6 years ago that I shouldn't have sold.

Did it jump a tooth on timing belt maybe? I also have a jet valve removal kit I don't need.

Timing belt is in good shape and timing is spot on. Do I need a special socket to pull the Jet Valves?

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Originally Posted by mitsumopar

Timing belt is in good shape and timing is spot on. Do I need a special socket to pull the Jet Valves?

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Just a deep socket is all it takes after you pull the rocker shafts.

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Originally Posted by camoit

Just a deep socket is all it takes after you pull the rocker shafts.

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Update: Did the leakdown test and got air in the cooling system on #3. So I pulled the head hoping for a bad gasket but think there is a tiny crack between the valves. Anyone have an outlet for a good used nonjet head?

some of the guys have had real good luck with clear water heads. There out of Florida I think.

Quote:

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Originally Posted by camoit

some of the guys have had real good luck with clear water heads. There out of Florida I think.

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Thanks. I dropped the head @ the machine shop to have it checked out. If he can't do anything with it I'll check out clearwater.