I checked the linkage multiple times, it is not binding.
I'll test for intake leak next.

Idling up high, running hot and dieseling when you shut it off sounds like vacuum leak.

I do not have any experience with the Predator carbs but that could be your problem to.

quote:

Originally posted by truckman:

The biggest problem came when I got back to the pits. The motor would not idle down, stayed at 2500 or so, temp was right around 210 which is normal for an LS.
When I tried to kill it, it dieseled a ton before stopping.
At this point I've spent a lot of time tweaking the Predator carb and it may be time to give it up.
I'm looking for a Holley or something I can run one time to see if that's my problem.

If I remember correctly from so long ago, it seems there were many who had idle problems with those carbs. Among many other things. In any event it is adding another unnecessary variable that a normal carburetor should take away.

After I check for vacuum leaks, I'll try to borrow a normal 4 barrel to try. If that works, I know what my next step is.

On the plus side, the car went straight, would've been a pretty good run if not for my bad reaction.

Practice makes perfect. Ther's no such thing as too much seat time.

Update. I dumped the Predator, got a Holley Ultra, 4-barrel double pumper.
Starts and idles MUCH MUCH better.
I have a stumble at initial throttle hit, found the nozzles were in opposite of how they should be, 31 front 28 back. Reversed those and it got a little better. Also the spring on the forward accelerator arm was collapsing instead of pushing the arm down. A couple washers increased the tension and now I get a good squirt of fuel. I moved the cam screws to position 2.
I still have the stumble so I'm getting bigger nozzles. Can't run this Saturday and it looks like rain Sunday so may have to wait a week to see how it does.

quote:

Originally posted by truckman:
Update. I dumped the Predator, got a Holley Ultra, 4-barrel double pumper.
Starts and idles MUCH MUCH better.
I have a stumble at initial throttle hit, found the nozzles were in opposite of how they should be, 31 front 28 back. Reversed those and it got a little better. Also the spring on the forward accelerator arm was collapsing instead of pushing the arm down. A couple washers increased the tension and now I get a good squirt of fuel. I moved the cam screws to position 2.
I still have the stumble so I'm getting bigger nozzles. Can't run this Saturday and it looks like rain Sunday so may have to wait a week to see how it does.

On the carb blow out the air bleeds with carb cleaner. When you blow them out you are looking and listening for them to flow though cleanly.
Verify float level, if it is low then it is leaner. If it still stumbles, open up your idle mixture some and see if that helps. If it does then continue adding more fuel with nozzles.

quote:

Originally posted by truckman:
Update. I dumped the Predator, got a Holley Ultra, 4-barrel double pumper.
Starts and idles MUCH MUCH better.
I have a stumble at initial throttle hit, found the nozzles were in opposite of how they should be, 31 front 28 back. Reversed those and it got a little better. Also the spring on the forward accelerator arm was collapsing instead of pushing the arm down. A couple washers increased the tension and now I get a good squirt of fuel. I moved the cam screws to position 2.
I still have the stumble so I'm getting bigger nozzles. Can't run this Saturday and it looks like rain Sunday so may have to wait a week to see how it does.

It would be helpful if you provided the size of the carburetor & if it's new or used?

Don't rule out power valve to help with the issue.

2BKING

quote:

Originally posted by truckman:
Update. I dumped the Predator, got a Holley Ultra, 4-barrel double pumper.
Starts and idles MUCH MUCH better.
I have a stumble at initial throttle hit, found the nozzles were in opposite of how they should be, 31 front 28 back. Reversed those and it got a little better. Also the spring on the forward accelerator arm was collapsing instead of pushing the arm down. A couple washers increased the tension and now I get a good squirt of fuel. I moved the cam screws to position 2.
I still have the stumble so I'm getting bigger nozzles. Can't run this Saturday and it looks like rain Sunday so may have to wait a week to see how it does.

Glad to hear you have things heading in the right direction. If you do need different size nozzles I would suggest looking into the new style from BLP. They have two exit holes on each side that squirt at different angles. One toward the booster and one lower. I started using them and they work really well. I was able to decrease the size of nozzle on my alcohol carb.

https://blp.com/product/billet...p-discharge-nozzles/

quote:

Originally posted by Curly1:

quote:

Originally posted by truckman:
Update. I dumped the Predator, got a Holley Ultra, 4-barrel double pumper.
Starts and idles MUCH MUCH better.
I have a stumble at initial throttle hit, found the nozzles were in opposite of how they should be, 31 front 28 back. Reversed those and it got a little better. Also the spring on the forward accelerator arm was collapsing instead of pushing the arm down. A couple washers increased the tension and now I get a good squirt of fuel. I moved the cam screws to position 2.
I still have the stumble so I'm getting bigger nozzles. Can't run this Saturday and it looks like rain Sunday so may have to wait a week to see how it does.

On the carb blow out the air bleeds with carb cleaner. When you blow them out you are looking and listening for them to flow though cleanly.
Verify float level, if it is low then it is leaner. If it still stumbles, open up your idle mixture some and see if that helps. If it does then continue adding more fuel with nozzles.

Good idea, I'll do that.

quote:

Originally posted by B KING:

quote:

Originally posted by truckman:
Update. I dumped the Predator, got a Holley Ultra, 4-barrel double pumper.
Starts and idles MUCH MUCH better.
I have a stumble at initial throttle hit, found the nozzles were in opposite of how they should be, 31 front 28 back. Reversed those and it got a little better. Also the spring on the forward accelerator arm was collapsing instead of pushing the arm down. A couple washers increased the tension and now I get a good squirt of fuel. I moved the cam screws to position 2.
I still have the stumble so I'm getting bigger nozzles. Can't run this Saturday and it looks like rain Sunday so may have to wait a week to see how it does.

It would be helpful if you provided the size of the carburetor & if it's new or used?

Don't rule out power valve to help with the issue.

2BKING

Sorry 750. Lightly used, allegedly it was too big for the first motor it was on and too small for the second motor.

quote:

Originally posted by CURTIS REED:

quote:

Originally posted by truckman:
Update. I dumped the Predator, got a Holley Ultra, 4-barrel double pumper.
Starts and idles MUCH MUCH better.
I have a stumble at initial throttle hit, found the nozzles were in opposite of how they should be, 31 front 28 back. Reversed those and it got a little better. Also the spring on the forward accelerator arm was collapsing instead of pushing the arm down. A couple washers increased the tension and now I get a good squirt of fuel. I moved the cam screws to position 2.
I still have the stumble so I'm getting bigger nozzles. Can't run this Saturday and it looks like rain Sunday so may have to wait a week to see how it does.

Glad to hear you have things heading in the right direction. If you do need different size nozzles I would suggest looking into the new style from BLP. They have two exit holes on each side that squirt at different angles. One toward the booster and one lower. I started using them and they work really well. I was able to decrease the size of nozzle on my alcohol carb.

https://blp.com/product/billet...p-discharge-nozzles/

Those are pretty cool, i may have to get some.

If you have the carburetor off take a look at the transfer slots, the butterfly of the carb should have them squared. If the front is open too far and the back is completely closed adjust the backs. It's common for the idle to be turned high to compensate for a cam and the primarys are running on the transition circuit. This will cause a bog or hesitation. Also understand how the accelerator pump springs work and why they are there. There is an adjustment procedure and if you make them too tight you can rupture the diaphram. Larger squirters can help but I've had to change the pump cams also to cure a bog on a footbrake car. Again if you change the cam you have to re-adjust the spring length on the arms of the acc. pump.

Carb is on but takes only a minute to remove. I will check the slots, thank you for that info.
I used a small flat washer and a small lock washer to get more tension on the spring, I'll remove the lock washer, in case it's too much. Or just replace the spring. Trouble is there's no speed shops locally anymore so anything like that I need has to be ordered online and wait, or drive 3 hours to Summit.
I need to replace the fuel bowl gaskets, and I have a minor fuel leak on the secondary acc. pump.
I may have to replace that diaphragm.
Not a footbrake car, has transbrake. I think I said that I moved the cam screws to the #2 hole, I know there's different colored cams, with different profiles, I might end up adjusting those.
I've been doing as much research as I can but getting advice from people who've done it is really valuable.
Thank you.