well im well into the build up of my 82 yota and got it running about two weeks ago. The problem im having is when I step on the spin-o-tire pedel it stumbles for a second and then take off. No matter what RPM when you step on it, it stumbles. Vac advance?,Accelerator pump? This is the second carb ive put on and it still stumbles. I had to swap the accelerator pump over to the other carb I put on because it had no pump thats why I say it is probally the pump. Any input would be greatly appreatiated(<- did I spell that right)

 

is it squirting gas down the throat of the carb when you hit the pedal? that'd be the accelerator pump.

also, does it puff any black smoke when you get on it? that could be a sign of a blown AAP diaphragm, which is very common and can make for some real irritation.

other than that, a vacuum leak could also make for a boggy carb.

 

no black smoke at all burns very clean. what and where is the AAP valve?

 

i have the same problem???

 

today I took a screw driver and manually pushed the accelerator pump in about 10 times while it was running with absolutely no change in the RPM's but thats the second accelerator pump. HMMMMMMM?????? neither of which were new though but there were no rips in the diaphram does that make it a good accelerator pump??? Hope someone can help because im ready to crazy..........er.

 

When I changed mine out there was no rips, but the diaphram was solid. It should move freely and flex...kind of like a bass speaker.

How is the timing, slightly retared will cause it to do that. Is the vac hoses on the dist all tight? no cracks. Wondering if the vac advance is working correctly.

 

put a brand new one on today and tried it again, nothing, so I grabbed the old screwdriver and manually pushed the pump in about 10 or so times and it built pressure behind the diaphram but would not come out the jet down the throat of the carb. This is the 2nd carb and 3rd accelerator pump the next thing I try is a 20lb sledge hammer, that'll fix the carb now wont it, hahaha!!!!!

 

I'm only asking because it is not mentioned, you did get that little spring back in there as well?

I'm sure you did, but it seems worth asking with the problems your having.

 

sounds like you might need to rebuild the carb. if there's not fuel coming out of the pump jet, that's your problem. probably some junk stuck in there.

 

kyle22r that was exactly the problem. Today on my way home from work I stopped and worked on my truck for a couple of hours, rebuilt the carb and in my rebuild I found the brass tube that comes from the accelerator pump orfice was plugged up tight. So I took a micro drill(about1mm) around and bored out the brass tube and kept stepping up a size drill until I was at stock size, but made the hole 2 sizes bigger for more fuel upon acceleration. IT WORKED AWESOME!!!! tons of power now and absolutely no hesitation what so ever.

 

4stair I would try doing what I did maybe it'll work for you as well.

 

awesome!!! i am gonna buy a rebuild kit anyway since it needs it probably.
i will check out that orfice for obstruction also....