No power and idoling at 2k rpms

[tyler111991]

I picked up this truck the other day. the truck I had before this was a 1992 Silverado 3500 with a 6.5 turbo diesel. Before that I owned another diesel. I know nothing about gas motors, especially carburetors haha. So the truck starts pretty good in the cold, I have to hold my foot on the gas to keep it running for a few minutes but after that its fine. However when I take off and shift into the next gear, its cuts out really bad. It does this is all of the gears. After I drive it and come to a stop, its idoling at 2000 rpms. I took it on the highway and got it up to 70mph and it couldnt pull a hill, I had to drop it into 4th and still barely made it up it. The truck does not seem to want to rev up over 3000rpms. The truck is a 86 ram 50 with a 2.6L and 5 speed manual. If anyone could give me some ideas on what to do\check I would greatly appreciate it. thanks in advance, Tyler

[tyler111991]

update. I was looing at the carb and opened the throttle all the way and only one of the nozzles are quirting fuel. The other side was not

[camoit]

Sounds like a vacume leek AND OR the fuel filter is needing to be replaced. Now for the fast idle somthing is holding the throttle open.

[tyler111991]

No I dont think the throttle is hanging up on anything, I cleaned it really good with carb cleaner the other day. How should I do a vaccum check? thanks

[camoit]

Well first you need to check and see if the choke is working corectly. On a cold enging. Pull the air cleaner. Then hit the gas pedal just once. Look at the carb choke it should be closed. Take note of the throttle butterfly position. Then start and let it warm up. The choke should open up slowly. You will see linkage that that conects the butterfly and choke together. If it working corectly then the choke will open and the throttle will move just slightly closed. There is a steped cam that controls the butterfly position untell the engine is warm. You might want to go to the manuals section and look in there. There is a first gen factory manual you can look at and learn about how the carbs operate. Yes it is the same as what you have. It tells you everything you need and gives you pictures. Take a look and fallow the flow charts in it.

[tyler111991]

I checked the choke this morning and watched it until the motor warmed up, its functioning properly. I will go check in the manual section. Thanks for the help

[tyler111991]

can the diaphram that is controling the second barrel be bypassed? It wont open, even when i try to move it by hand

[Ramit]

Not sure why you would want to bypass the second barrel. That is probably the reason why the truck wouldn't pull a hill. You are basically running a 1 barrel carb until you get the vacuum operated secondary fixed.Is it that the butterfly is seized shut in the carb, or is it simply that the diaphragm is bad? I would definitely lean towards the bad diaphragm. Quick test-with engine off, remove air cleaner. Disconnect the opposite end of the vacuum line that goes to the diaphragm.This is easier to do with the choke all the way open. With one hand, hold the throttle wide open, or have somebody hold the gas pedal to the floor. Now, with either your mouth or a vacuum pump, apply vacuum to the diaphragm. Look directly down the throat of the carb. You should see the secondary butterfly open. It should stay open with steady pressure on the vacuum. If it even starts to close even a little bit with steady vacuum, your diaphragm is bad. Let us know what you find out.

[tyler111991]

I was talking about hooking up the second butter fly to work off of the throttle cable instead of vacuum, not bypassing it all together haha.
I did the vaccum test on the diaphram, it opened up all the way. When I tried to move it by hand it wouldnt budge but with the throttle open and vaccum on it, the butterfly opened. I looked at oriellys and autozone and couldnt find a new diaphram, do you know where i might be able to find one?

[Ramit]

Did the butterfly stay open with a steady vacuum, or did it slowly start to close on its own? Thats the question you need to be answering. If you can't get it to stay open with steady pressure, then it needs to be replaced. I got one from a place in El Monte, CA. called Carburetor Exchange (626) 444-2633. The part cost $75.00, plus $10 shipping to TN.