engine and drivetrain Diagnostic Help & Advice Wanted

[Guest Anonymous]

My '02 won't idle, runs rough, bucks and surges since I installed a rebuilt 32/36.

I have a 76 02 with a 73 engine transplanted into it. I'm trying to get it back to roadable condition. I determined that the Solex was unsalvagable, but I had a used Weber 32/36 available. I installed the usual rebuild kit - gaskets, needle valve, power valve. Set the float level per Haynes Weber book spec. Used the C.D. prescription for jets. Fired it up and it seemed to run pretty well but I didn't drive it, just let it warm up and checked for leaks.

Next day I started it again and it had developed a miss at idle. Warmed it up, tried to take it on the road. Very poor runnability. Bucking and surging. Pulled back into the garage to look it over. Set the idle mixture to one turn off all the way in, started it up and backed out to best RPM. But all the time the idle is very unsteady. It will idle at about 1000 for a while, then drop, sometimes it will pick back up, other times it contiues to drop to the point that it will die if I don't blip the throttle. Then it will idle some more for a minute or two and do it again. Still poor drivability.

I've rechecked the timing, retorqued the mounting nuts, sprayed carb cleaner around the base and throttle shaft to see if there were leaks - no significant change. Also pulled the idle solenoid valve and verified it works, it goves me a good solid click when I connect or disconnect the power lead, but disconnecting it doesn't make any difference in the way it runs - that seems odd to me.

Before I decide this carb is junk and buy a new one, anyone got any suggestions?

[Guest Anonymous]

1. Vacuum leaks--hoses, loose carb, warped mounting base etc.

2. Vac advance diaphragm in dizzy--that can cause described symptoms

3. trash in idle jets (there are two)

4. Didja reinstall the venturi "bridges" in correctly? They only work in one position but can be easily installed backwards/upside down.

5. Float level is incorrect/float &/or needle valve is sticking.

6. Choke not fully turning off

That should get you started....

Mike

[Guest Anonymous]

Thanks Mike, sometimes you get discouraged and need a reminder that there are still things to do.

The clogged jet is very likely. And it's always worth checking the float level. Any cure you know for a sticking needle valve? It's new.

I think I would have noticed a warped base, but can check. I also think a vacuum leak would have showed up with the old carb, not to mention spraying carb cleaner onto every gasketed joint looking for just that. Maybe it's time to risk using ether.

Again, the dizzy was fine with the old carb, and pulling off the hose didn't help. The choke butterfly is definitely working fine. That was my first concern. The venturi bridges in wrong would probably act a whole lot worse than it is acting now. Upside down probably won't go at all, backwards is pretty clear because you have to match up the passages.

[Guest Anonymous]

For some reason some people cut that needle....

[Guest Anonymous]

1. to check dizzy vacuum capsule, remove hose from carb and suck on it. You should feel resistance

2. A new needle valve shouldn't stick. If it does, take it back and get another one.

3. A warped base might not have shown up before you removed the carb, as the warpage might have been plugged with dirt. I'd look for other stuff first, tho.

Hope you find it easily...

Mike

3. Trash in idle jet is very likely as the orifice is very small and clogs easily