Okay it is not a new problem but I thought the new Weber would make it go away. While it still had the Hitachi on it, the car would hesitate and jerk while under slight loads in 3rd and 4th. In 4th gear it would be so bad that it would eventually sap all your power. I could floor it and it would come out of it and I could drive down a hill and it would be fine. It is only while under a load. It is bad enough that I think it is dying but when I stop, it idles fine. It does not pop or backfire out the carb so it acts like a fuel problem. The valves are adjusted fine, the timing is on. You always could hear a slight miss at the exhaust and while it is better, it still acts somewhat like there is a spitting to it. The old hitachi was doing the same thing but it was getting awful leaky on gas so I took others advice and upgraded hoping the problem would clear up. It did not. Here is what has been done with the Brat. I have a NOS fuel tank, new fuel pump, new filters, new regulator set on 2.5psi, new Weber from Redline, new oil pump, coil, new plugs, disty cap and rotor. The only thing not changed is the plug wires and I will do that tomorrow. I could try to adjust the carb some more but considering that the problem was there before the swap, I am sure I will not work it out that way. I am starting to believe I am not meant to win at this. I have not checked the compression but the engine ran great for a while then just stared doing the cut out thing. I am suspicious of the fuel pump. The engine is an 83 that was supposed to be an airplane transplant until someone lost interest. I need another crank to rebuild the original 85 in my shop. HELP......AGAIN IT is getting to be an awful pretty lawn ornament and way too expensive to sell.

I could be off base here, but I have seen several cases of ethanol flaking off zinc inside of some carbs, plugging them up and ruining them. Are you running a percentage of ethanol or E85 by chance? Have you tried propane enrichment to see if it helps? Just some off the wall thoughts. Sure do wish you good luck as this sort of thing can be maddening. Start by taking a fuel sample in a clean glass jar and examine it carefully for proper odor, color, particulates, ect.

i would almost bet my car on the plug wires..

I'll bet his car it's not the wires.

If new wires don't fix it, I'll gladly get rid of that eyesore of a lawn ornament for you free of charge! =P hehe

 

Hopefully new wires fixes it. Good luck!

hey... I had a similar problem with my '85 EA82. It was hesitating and bucking slightly under a load. Downhill and rpms > 3500 it ran OK.

Turned out to be the distributor. I swapped in one from another car... actually an EA81 disty. And it fixed the problem.

Although, another symptom I had was the tack was jumping around. Not sure if your tach is doing this.

Try swapping distys. I had the disty rebuilt for $150... Philbin in Portland, OR.

Hope this helps... Ron W.

ok simular probs whit my 84 brat, tried all sorts of stuff no carb swap though, I am now running an ea82 ditsy that fixed the starting crap, then i got rid of most of the EPA crap that fixed the sputtering and stumbleing, now I just have a small issue in between cold and totaly warm, but so much better, now I can accually drive the beast and enjoy...............G

Very sad but I have been very lazy this summer. Too hot to work on anything. I swapped out my disty with the other one I had and it fixed the stumbling but now the fuel pump does not give that 7 or 8 seconds of gas to the engine upon first turning the key. Once the engine actually fires I get 12.4 volts to the pump and it works fine. During cranking I only get 9 volts and the pump does not pump. It will be a problem as long as the thing sets for a while and there is not gas in the carb to get her going. What do you think, should I just bypass it altogether and run a hot wire (switched of course) to the pump or what?

Very sad but I have been very lazy this summer. Too hot to work on anything. I swapped out my disty with the other one I had and it fixed the stumbling but now the fuel pump does not give that 7 or 8 seconds of gas to the engine upon first turning the key. Once the engine actually fires I get 12.4 volts to the pump and it works fine. During cranking I only get 9 volts and the pump does not pump. It will be a problem as long as the thing sets for a while and there is not gas in the carb to get her going. What do you think, should I just bypass it altogether and run a hot wire (switched of course) to the pump or what?

 

PO bypassed the fuel pump on my brat (dont know why) been that way for years, works fine.

Have done this on a few vehicals aswell

Once had an 85 EA82 with the same symptoms. Turned out a small vacuum line connected to the intake manifold over #1 cylinder was cracked. How such a small vacuum leak could cause such a large problem was and is still a mystery to me.