She's runnin but not good

Vanspeed

Vanspeed

Well-known member
I got the motor in my truck started today. Idles kinda rough and when I step on the gas it wants to caugh, backfires and sometimes dies. I set the timing according to Marco's site. Any suggestions to look at?
 
Like gary says: Timing, gas flow. And: bad gas, condenser, coil, coil wire, etc. Is this an engine you had, or just acquired with the p/up?? By the way, nice job.
Paul in CT
 
Could you swap out the carb with a known good one, like maybe from that coupe in your avatar, to make sure that's not the problem?
 
Does seem to have a leak around the exhaust manifold. New gas, I did not go all the way threw the carb so maybe that has some issues.
 
runs really rough too, shakes the cab and front fenders pretty good. I admit, when it comes to model a's, this is where I am not that good.
 
Vanspeed, I am not that good at A's either but it sounds like maybe your rig is getting to much gas. Does it blow black smoke out the tail pipe? Is the mixture screw set correctly? Does the adjusting needle thingie (as you can see is don't know all the terms) screw in far enough to cut back on the gas used? I know when I try to screw mine in sometimes, it binds and will not cut back on the gas and it will run ruff. Just my $.02 worth.
 
Ok, exhaust manifold is leaking, I can see carbon on the block around the ports. This was a mis-matched exhaust manifold/intake manifold so that may be a problem. Can you surface manifolds when they are bolted together to make sure they have a uniform seal on the block? Exhaust is also leaking at the pipe (explains why it is so loud). The points appear to be correctly set and the timing does seem to be on spot. I have the gav at 3/4 turn out, and the mixture screw on the carb is 1 revolution out. I am going to correct the intake/exhaust manifold first and go from there. I was really hoping that it was just going to start right up and purr but no luck. Also has no power at all. No black smoke coming out of taillpipe that I can tell.
 
Vanspeed said:
Ok, exhaust manifold is leaking, I can see carbon on the block around the ports. This was a mis-matched exhaust manifold/intake manifold so that may be a problem. Can you surface manifolds when they are bolted together to make sure they have a uniform seal on the block? Exhaust is also leaking at the pipe (explains why it is so loud). The points appear to be correctly set and the timing does seem to be on spot. I have the gav at 3/4 turn out, and the mixture screw on the carb is 1 revolution out. I am going to correct the intake/exhaust manifold first and go from there. I was really hoping that it was just going to start right up and purr but no luck. Also has no power at all. No black smoke coming out of taillpipe that I can tell.
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The only way you can surface them correctly is if they are bolted together.
 
Should I put the original intake back with the exhaust manifold, I have it just went with the other one I had because it was already panited. I am ordering points, a new exhaust/intake gasket (which is the best?) swapping out intake manifolds and I noticed my wire going to the coil from the terminal box has only about two wires still holding it together.
 
New wires or harness aren't too expensive, so I'd buy new, unless you have an excellent original harness and it only needs a small repair.

I like the copper gasket.
 
Vac leak and that wire may be it. Would re-verify your timing. Compression test?? Plugged muffler. Ditto on the copper two piece (slots) gaskets.
Paul in CT
 
Probably not a large contributor, but on my A setting the GAV 3/4 turn out leads to rough running engine as soon as she starts to warm up a bit. I know they're all different, but you might try leaning down the GAV and see if that helps. Good luck!
 
Is the port for your vacuum wiper open? Is the hose at the vacuum wiper open? Check the entire vacuum wiper line, or better yet, disconnect it from the manifold and plug that port to see if it runs better.

The intake/exhaust manifold need to be surfaced together. They must be bolted together and then the old way was to surface them on a sanding table... The kind that has a belt of sand paper running under the manifold making it flat.
 
James Rogers said:
The only way you can surface them correctly is if they are bolted together.
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On the other hand, I've read that it's best to surface them independently and mount them semi-independently. Leave the two bolts that hold the manifolds together loose until after the big studs have been tightened, so that each unit can be optimally seated. This allows for better accomodation to any surface irregularities.

Steve
 
steve s said:
This allows for better accomodation to any surface irregularities. Steve
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Your block should be flat at the exhaust ports...

Therefore the manifold should be flat...

the gaskets allow for accomodation to any surface irregularities. If you have surface irregularities that a gasket cant fix, you have a problem with your block.
 
No vacuum line, 29 pickups had manual wipers and the plug is in the intake. I am going to swap out the intake on it to the one that was originally with it. Then surface them if need be. Parts will be here tomorrow so hopefully I will have some good news.
 
Pilotdave said:
Probably not a large contributor, but on my A setting the GAV 3/4 turn out leads to rough running engine as soon as she starts to warm up a bit. I know they're all different, but you might try leaning down the GAV and see if that helps. Good luck!
Click to expand...

I have found the same thing with my huckster. With the GAV a little to far out, it will run ruff.
 
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