Help for a new guy

[GMCDAC]

Originally Posted by Vern

OK, I replaced the distributor cap, rotor, wires, and adjusted the timing. Today I drove it to a shop on the maiden voyage to get the brakes inspected. When I pushed the choke in all the way and tried to get it out of first, it stalled every time. When I pulled the choke out a little bit, I was able to drive it. Very rough and my wife complained that I smelled like an old gas rag when I got home, but I was able to get it up to 50 MPH. Any ideas about what is going on?

Don't think I have helped much here and this is probably not the problem either, but it happened to me when I built my Rochester M the first time. I bought 3 disassembled Rochesters, 1 model M (manual choke) and 2 MV's (automatic choke) parts carbs to build one good one and the plan went fine, as I wanted the Model M. It ran rough but idled pretty good. Since all 3 carbs were completely disassembled I had put the metering rod spring under the power piston arm instead of on the top. The drawings in the kit instructions did not show the spring position, so it was a guess.

The pic is of one of my parts carbs and how the spring should be positioned.

Later---DAC

[Vern]

I'm trying to troubleshoot things without pulling apart the carb. I replaced the points and set the timing about 3-4 marks above 0 (TDC). I adjusted the fuel mixture. It runs better, but the only way to get it to highway speed is by pulling the choke out 1/4-1/2". One thing I noticed is that when I was going down a long steep hill in 1st, blue/white smoke poured out; it doesn't do this when idling. I hope it's not burning oil (?).

[FetchMeAPepsi]

IDK about the I6, but the V6 only has a couple of marks for timing. If you set it 3-4 marks on that motor you'd be at like...+15 on timing


Are you sure that's right?

[tommyduncan]

Originally Posted by Vern

I'm trying to troubleshoot things without pulling apart the carb. I replaced the points and set the timing about 3-4 marks above 0 (TDC). I adjusted the fuel mixture. It runs better, but the only way to get it to highway speed is by pulling the choke out 1/4-1/2". One thing I noticed is that when I was going down a long steep hill in 1st, blue/white smoke poured out; it doesn't do this when idling. I hope it's not burning oil (?).

so it idles OK but you can't get it moving without having the choke partly on? Does it die just above an idle without the choke? Do you leave it on or push it back in after you get going?

[Vern]

Originally Posted by tommyduncan

so it idles OK but you can't get it moving without having the choke partly on? Does it die just above an idle without the choke? Do you leave it on or push it back in after you get going?

I was driving it 50-60 MPH with the choke still on. If I pushed the choke in, it would run but was really rough. I can get it rolling with the choke off, but it has to be revved pretty high to get it rolling.

[Rockdriller]

Originally Posted by Vern

I was driving it 50-60 MPH with the choke still on. If I pushed the choke in, it would run but was really rough. I can get it rolling with the choke off, but it has to be revved pretty high to get it rolling.

Congrats on a great truck.
Boy, that is a nice one.
Well, Vern....I've been readin along and I might have missed something, but I might be able to help you out..
First of all....rule of thumb is....If you need to choke your engine to get it to straighten out...then you're probably fuel starved. When you pull the choke, you reduce the airflow in, which makes it run better because you improved your air to fuel ratio.
It can be anything from a fuel filter to a poor fuel pump to a blocked port inside of your carb.
So think along those lines....maybe you can figure it out.
Of course, I might be wrong.

[Vernski]

Sounds just like a clogged fuel filter, replace the one inside the carb if you have already cleaned it it may still have shellac in it..Vernski

[WDShaffer]

Agree with all that advice - sitting still isn't good for us or our trucks. Engine either fuel starved, or you have a leaky intake gasket leaning up the mix. Easy way to eliminate a leaky gasket is with a can of starter fluid. Get the engine idling smooth and slow. Spray the starter fluid in short bursts at each side of the base of carb, and wait between shots. Follow this procedure around each port. If idle doesn't change, no leak and proceed with fuel delivery troubleshooting.

I've had to deal with plugged accelorator jets too; like Vernski said, fuel starvation for 1 reason or another.

[Rockdriller]

Originally Posted by WDShaffer

Agree with all that advice - sitting still isn't good for us or our trucks. Engine either fuel starved, or you have a leaky intake gasket leaning up the mix. Easy way to eliminate a leaky gasket is with a can of starter fluid. Get the engine idling smooth and slow. Spray the starter fluid in short bursts at each side of the base of carb, and wait between shots. Follow this procedure around each port. If idle doesn't change, no leak and proceed with fuel delivery troubleshooting.

I've had to deal with plugged accelorator jets too; like Vernski said, fuel starvation for 1 reason or another.

Rodger all that.
(This procedure A.K.A.: Free Basing the Top End)

I am also a firm believer in WD's advice to "wait between shots"....

[Vern]

Originally Posted by Rockdriller

Congrats on a great truck.
Boy, that is a nice one.
Well, Vern....I've been readin along and I might have missed something, but I might be able to help you out..
First of all....rule of thumb is....If you need to choke your engine to get it to straighten out...then you're probably fuel starved. When you pull the choke, you reduce the airflow in, which makes it run better because you improved your air to fuel ratio.
It can be anything from a fuel filter to a poor fuel pump to a blocked port inside of your carb.
So think along those lines....maybe you can figure it out.
Of course, I might be wrong.

The truck is rough, but hopefully a good one some day! I've replaced everything from the gas tank down to the carb, which I rebuilt (perhaps badly). So, there's no clogged filters and the pump is new. I've only run ethanol-free gas through it so far. Based in the condition of the carb (was really crusty and pitted on the inside), I'm hoping Santa Claus (or a thanksgiving turkey) will get me a rebuilt one. Just trying to eliminate other problems, such as something with the distributor.