Hi Folks,
I have a carburetor issue. It’s a 2100 and was rebuilt about a month ago. I’ve been dealing with this issue ever since then. I’m just getting time to work on it. Here are the symptoms.
1. Truck starts up fine in the morning. Electric choke good.
2. I drive the truck around for about a 1/2 hour. Turn the truck off and try to restart. No problem.
4. I Let it set for more then a ½ hr and it will not start without pumping the gas 4 to 5 times.
5. Lots of gas fumes, probably due to the excessive gas pumping.
6. No problems driving it around.

Thanks,

 

Sounds like the float has a hole in it. Fills and then when you shut it down it sinks enough to hold the needle open draining the bowl. If not that still sounds like the needle is open when it should be closed.

 

Next time you try step 4, instead of pumping the gas 4 to 5 times (which will flood out the carburetor and mask the issue you're trying to solve), gently hold the gas pedal down about 1/3 of the way, then crank the motor over with the pedal held there. If it fires, let off the gas. Does this procedure work instead?

 

Thanks for the replies.

Had the float replaced at the time of rebuild. I verified the 7/16 setup yesterday. It was a little off. No change.


I tried step 4 with 1/3 pressing peddle. Started in 10 to 15 sec. A little long. My 78 starts in less then 3 sec.

 

Regardless of having the float replaced it may still have a pinhole in it. Possibly dirt holding the needle open.

 

Ok. Installed a new floater and needle. No change What ells could be going on?

 

Check to verify the throttle plate is closed when the truck is hot and off. When the truck is hot what is the idle RPM? Automatic or manual trans?

 

It's possible that fuel is seeping past the threads of the power valve, or a hair-line crack in the fuel bowl is letting fuel seep into the intake manifold once it's warm. Since it started after the rebuild, the former is the more likely of the two.

 

Hadn't thought about that. In any case it sounds like the bowl is running dry or at least very low.

 

Elgemcdlf

I'll check the throttle plate when the truck is hot and off. I don't know how to check the RPMs and its an automatic.

fmc400

I did notice some fuel in the intake after removing the carb. Something is allowing the fuel to leak by. I read on how to check the float with carb on/gas. I've been checking the float with a dry chamber. I'm going to verify the power valvue.

I'll get back to you guys by end of week with results. Thanks again for the help.