Idle too high - Tried just about everything

[72Highboy]

First things first Welcome to the Site Robert.

Now just a little bit more info. What model of carb did your cousin buy it will help others that might have the same carb as your cousin give ideas that they found out and throw in how much the cfm is. But doesn't the more cfm mean more fuel or air is going into your carb. Wish I could help but carbs are a can of worms I havent open and dont plan on too for a while, but dont worry help is on the way.

Welcome again Robert.

[rgh69]

Thanks, glad I was able to find this site.

The carb is a Holley 600 CFM and here is a link to what he purchased.

http://shop.advanceautoparts.com/webapp ... 9413642___

[dbarker]

If you've adjusted the idle screws and it's still too high the ONLY thing I can come up with is the following two scenarios:

1) even though you've adjusted it, the idle hasnt changed because the carb is stuck at high idle. Try working the throttle on the carb and see if it idles down.

2) the throttle cable is set wrong and is causing the throttle to open partially, thus raising the idle speed. try adjusting the cable to have a little more slack to see if the throttle closes some more.

As said before, Welcome to the site. Carbs a can of worms that nobody really likes to open. In my experience you can have 4 identical carbs, none will be the same.

My 65 mustang had an older Holley 650 carb... it had a nice low idle so you should be able to get your carb down to earth.

Good Luck.

[fordman]

i would get soem more better gas and ad to what is already int he tank. it could be part of the problem. or it could be a timing issue too. you never know. check it or have it checked. that can make it idle too high also. does it have any trouble turning over before it starts? you know slow spinning of the engine or fast spinning of the engine? that could indicate incorrect timing.

[convincor]

it's usually the secondary lever on the passenger side that make contact if no spacer is used. You could also grind a little to clearence it.

[rgh69]

Thanks for the quick replies. I completely disconnected the linkage and started the engine. manually actuated the carb throttle and the idle is still too high. I don't have a timing light. One is on order though. I will dont see any timing marks on the pulley so I will have to manually find TDC and do some math when it gets here. I will also get some more gas and add it to the tank. Hopefully that will help. Apparently E85 requires 25-35% more fuel to air. So maybe it is running to lean. Would that cause high RPM?

[convincor]

did you look down the secondaries and make sure the throttle plate is closed?

[iamthewreckingcrew]

A bad vacuum leak(messed up or mismatched carb gasket) will make it rev too high also.

[Ranchero50]

Yep, I'm leaning towards a vacuum leak too. Sounds like a 2bbl to 4bbl adaptor was used. I'd suggest taking the carb back off and comparing the gaskets to the mating surfaces of the carb baseplate and the adaptor plate to see if they uncover one of the vacuum ports in the bottom of the Holley. Been there, more than once.

The timing marks are there, pull the distributor cap off and roll the motor around until the rotor is pointing to #1 cylinders spark plug wire on the cap and use some sand paper to clean the balancer under the timing pointer.

No drama
Jamie

[LANCE65]

Take a can of starting fluid w/the engine running and spray around the vacuum lines,carb,brake booster,intake.If the engine RPM changes,you have a vacuum leak. Fix that first. Then move on to fixing the carb. Also if you have an automatic trans go under the truck and spray around the modulator. Good Luck
-Lance

[cdeal28078]

I agree with Dragon. I think it is the secondary set screw OR the initial timing is set too high. I have also had a gasket hang up the throttle plates. I am betting on the secondary settings
clint