Minor idle irritation

[Norwester]

350 with an Edelbrock carb

The engine starts great. Choke seems to work fine. I jab the throttle and the RPMs drop. Problem is:

If I'm cruising down the highway, engine at full operating temps, and I stop for a light, the rpms do not go down to idle, maybe a few hundred above my low idle speed. If I jab the throttle, they drop to where they should be.

Not being extremely mechanical, can somebody point me in the right direction?

Thanks!

 

[MadOgre]

Use some carb clean and spray down all the linkage?

 

[Norwester]

Good place to start. So you think its simply a linkage issue?

 

[MadOgre]

Could be. Do you have a fuel filter?

 

[MadOgre]

Could also be a small vacuum leak on one of the vacuum ports too

 

[Norwester]

I'm sorry. I am tired of messing with vacuum.....please come up with a better answer, something that's easy to do. Like cleaning the linkage. I like that idea.

Seriously, thanks for the suggestions

 

[Norwester]

Oh, and yes, I have a fuel filter

 

[Georgeb]

I vote with MadO on cleaning up the linkage. If desired you can use some dry lube but nothing that will attract dust and dirt. You should also verify for sure the choke is all the way open. Automatic choke I assume. I would also check that the return spring is strong enough to pull it to idle consistantly. I have also seen a worn or sticky throttle cable cause this. I fought with one for a while untill I finally just replaced it.

 

[Norwester]

Dry lube......like graphite?

 

[Georgeb]

Yes, I like to spray it while it's running so the vaccuum pulls it in along the throttle shaft too. It sounds like if you jab the throttle it snapps shut but if you let off gently it hangs up. Can you post a pick of your setup from both sides of the carb so we can see the linkages and return spring??

 

[Norwester]

I can do that......Probably tonight

 

[Georgeb]

To troubleshoot you could give it throttle while parked and gently let off. Then go look to see if its hanging up. If you can push the throttle closed by hand and the idle dropps you have proven it's hanging up. Wash it down with cleaner and try it dry to see if it still does it. I would check that the choke is fully off and the high idle cam is properly disengaged. Then look at the spring and or throttle cable. It may be an easy gummed up linkage fix tho. After you eliminate any mechanical causes the the fun with vacuum can begin.

 

[Norwester]

Here are some pics.I cleaned the linkage and lubed with graphite. I haven't tried it yet. Only hung up once on my way home.

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[350runner]

Start by lubing the linkage if that doesn't work try replacing the carb to intake gasket. Center the carb b4 you tighten the bolts.

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[MadOgre]

God suggestions so far.

Also clean the throttle bores with carb clean just like you would any other carburetor. 1500rpm and spray down the throat with out killing the engine.