Posted by terry [65.95.4.163] on Friday, April 26, 2013 at 18:32:18 :
I have been trying to get a few bugs out of my Wc63 truck. The truck is completely rebuilt except for the 230 cu engine which will come out this winter. The truck takes a little time to get up to 30-35 mph and then after running at this speed for a minute or two it starts to stumble like its running out of gas. If I let of the throttle it recovers but still won't take any more pedal as it starts to buck again. Here is what I did so far....
1=Rebuilt the carb again and after pulling out every plug and jet. blew out all passgaes and replaced the gaskets and balls/ checked float levels as such. I set the float to 5/64" down from the bowl top as required. the needle and seat are new from the kit. This carb is off of a PW truck series E7T1.
2-found that after taking the fuel bowl cover off the carb I found I still have pressure between the seat and pump. when I push the float down the gas squirts into the carb bowl and when releasing the float it stops and does not flood.
3- I installed my old rebuilt M37 carb and ran the truck as well the same way. It also responded the same as before at the same speeds.
4-I installed my completely rebuilt petronix 6Volt neg ground distributor into the engine and set up the timing to 4 degress adv. I test ran the truck and it ran better but still had a slight bucking at the same speeds.
5- The fuel pump is brand new and is for a 230 engine with modern diaphrams inside it. It does hold pressure after shuting of the engine for a while as well. The gas tank, fuel lines and connections are all brand new steel with rubber only between the frame and the pump. The tank was steam cleaned and confirmed to be mint inside with no rust anywhere. I checked all connections and found them to be secure and sealed.
6- I checked the gas cap and it is not drawing a vacuum when the egine is running. The tank has about 1/2-3/4 of fresh fuel in it.
7- Yet at idle and any speed below 30 mph the engines runs smoothly and accelerates ok. There are no misses or pops in the exhaust or intake areas. The plugs are all new with a light grey coating on the electrodes from these test runs. It sure seems like that it is starving for gas at speed but maybe the carb is a little too small for the engine??. The same model carb is on my 230 PW and it runs great.. This engine is a little tired and has compression around 90-95 psi and pretty even across the engine but it starts and idles great.
Any suggestions as to why the gas starvation at 30 -35mph???. Terry
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