How to properly tune a Rochester Varajet?

[Mosinguy]

I am idling at about 800 rpm, but no matter what I either tune it too rich so it keeps going after I turn the engine off and then won't start afterwards (runs off fumes and drains the carb and inline pump), or too lean to where the whole truck shakes. Never did that until I decided to screw with the one idle adjustment screw by the linkages on the back of the carb because it wanted to try and die at a stop sign a few times. Any help is appreciated.

I run a 2.0 engine. I wish I could convince dad to let me trade for an EFI F150...

 

[eldirector]

Sounds like you found the mixture screw, not the idle screw.

Doesn't that have an idle control solenoid? It may not be adjustable manually (set by computer).

 

[Mosinguy]

Sounds like you found the mixture screw, not the idle screw.

Doesn't that have an idle control solenoid? It may not be adjustable manually (set by computer).

The Rochester only has the idle speed screw from what I understand. The other screws are capped from the factory to prevent user adjustments.

 

[Bigtanker]

If it keeps running after you turn the key off, you have a lot of carbon build up on the pistons. (Plus the carb problem). But to take care of the carbon, buy a can of SEA-FOAM fuel treatment and while the engine is warm and running, pull the brake booster vacuum line and pour about 4 oz in that line. It helps to have somebody keep the idle up while you do this. Let the motor run about 30 sec then shut it off. Let it sit about 5-10 min then go for a half hour drive. This will clean the carbon out of the motor.
This is called a hot soak and there are instructions for it on the can.

 

[Mosinguy]

If it keeps running after you turn the key off, you have a lot of carbon build up on the pistons. (Plus the carb problem). But to take care of the carbon, buy a can of SEA-FOAM fuel treatment and while the engine is warm and running, pull the brake booster vacuum line and pour about 4 oz in that line. It helps to have somebody keep the idle up while you do this. Let the kotor

Did this. Used the whole can in about 30 secs. Would I need more?

 

[eldirector]

Here is the manual for your carb (I think your truck is post 1980, correct?):
http://c777913.r13.cf2.rackcdn.com/rochester_e2se_manual.pdf

Should cover everything you need to know.

 

[Bigtanker]

Did this. Used the whole can in about 30 secs. Would I need more?

Probably not. But It won't hurt to try it again.

 

[Mosinguy]

Here is the manual for your carb (I think your truck is post 1980, correct?):
http://c777913.r13.cf2.rackcdn.com/rochester_e2se_manual.pdf

Should cover everything you need to know.

Yep, 1984. I'll look it over. Thank you.