Jimmy dies when put in drive or reverse

[SteedaLX]

I have a 1971 Jimmy 350 4brl. I just had the carburetor rebuilt and the guy tuned it for my truck. It has new plugs and wires. My truck starts up fine and idles with no problems; it also idles fine in neutral. If I drive it while the motor is cold it runs great; it feels very strong. Once it starts to warm up it goes to hell. If I pull up to a light or at a stop sign it will start missing and die. It will start back up fine but when I put it in drive or reverse it spudders and dies. If I happen to get it moving it will miss really bad, sputter and die. It is so wierd because if I come back the next day it will run fine for a while then do the same thing. Somebody said it could be the coil so I am going to replace it when I get home. Beside that does anybody have any other suggestions? I am going to take it back to the guy who does the motor work for me but I wanted to run through the basics before I took it in. Some also suggested I put an HEI distrubtor on it. Any help would be appreciated.

[jhow66]

Have you adjusted the idle mixture screws? Have you adjusted the idle speed screw. If it is not idling fast enough in netural it will die when you put it in gear because the convertor in trans will slow it down even more Did the guy adjust the carb after it was put back on truck?

[Leinie]

Are all the Vacuum lines reconnected in the proper places ?! Was the timing reset with the vacuum advance disconnected and plugged ?

[SteedaLX]

Yes he adjusted the carb after I put it back on the truck. It idles fine in park and neutral...it also idles fine when put in drive, for a while anyways. I checked the vaccum lines and everything looks to be connected. I assume if one of them were not connected it would not run right anytime. I don't really know anything about carbs so I will need to get him to look at that portion of it. I replaced the coil tonight and it was running fine.....it started raining bad so I didn't get a chance to ride around to see if the problem came back....hopefully tomorrow though.

[blazer1971]

Remove your air filter and check your choke both when first start up and after it warms up and you start having problems.

[old Rusty C10]

pickup coil in distributor?? sounds like what happened to me when mine went

[da-burb]

Sounds like a vacuum leak. Symptoms are; with the carb choked and a vac leak it runs good. With the choke open and the vac leak it is too lean to run. At idle it would be fine, under load it would miss and/or die.

I would check at the base of the carb if you don't find any lines off or split. I would also check the vac advance on the distrib(could be a ruptured diaphram), listen at the brake booster if you have power brakes, and check to see that the Vac modulator is hooked up on the tranny if you have a TH350.

[SteedaLX]

Not for sure if this could have anything to do with it but after I got it back from the guy who tuned the card it has been leaking transmission fluid. At first it was a little bit but now it is pretty bad. I haven't been driving it since it really started leaking. It looks to be leaking right up by the motor.

[krue]

What kind of tranny? Check your vacuum modulator, there should be a vacuum line running from the carb to the pass rear side of the tranny (if it's a th350). If the modulator diaphragm has a hole and the line isn't connected you could get fluid. You would also have a vacuum leak.

[SteedaLX]

It is a TH350. If the line was not connected how much would that cause it to leak? This is a pretty steady drip until about a quart as leaked out. It pretty much stops then.

Thanks again

[robby]

Did you ever find out what was wrong with it?

[SteedaLX]

I have fixed part of it. The transmission coolant line was what caused that leak. Which turned out to be really nice considering I was thinking the worst. I have checked the carb for any kind of vaccum leaks and nothing looks to be out of place. I haven't driven it but i'm sure it will do the same thing. I will probably take it to my friend this week and let him check out the carb....since that has to be it.

[SteedaLX]

I took my truck back to the guy and he fixed it. He has the choke tied open and apparently it had come loose and was shutting. He said that was causing it to die.

[Grim Reaper]

Choke.

It's not coming off once it's warmed up. It's flooding out.

I gave up on divorced chokes like your truck has long ago. Went electric of got 78 up Quads and coverted them to electric.

For the record I question what the heck he was doing with "Tie off the choke". Sounds like he has not got it hooked up at all. He's probably running the idle mix fat to make up for it with the cold weather. I bet your going to have more trouble when it warms up! I'd convert it to manual.

[SteedaLX]

Correct when I bought it the choke was not hooked up; so he just used some plastic ties so it is always all the way open. Like I have said I don't know jack about carbs. Will this be a problem for me? I am thinking about getting one of the off-road carbs by holly or edelbrock.

[blazingfun]

might ckeck if gas tank is venting properly

[Blue Beard]

In my mind what he did to the choke may lead to other issues down the road........so to speak.

He's a mechanic, why not fix it right the first time.