Engine Idle issues

[Mike4130]

I'm having some issues with my trucks idle. It seems that it idles really high after I let go of the throttle after a big acceleration, enough to keep the truck moving on its own for 10+ feet, then it will drop down to normal idle. Even at a stand still the RPM's will vary from low to high,then back to normal. I somtimes will have to hold the brake to keep it in place. I've adjusted the low speed needle, but the RPM's are all over the place. I was planning on spraying carb cleaner on it today to clean off the vents/breathers, has anyone had any issues with that? Thoughts?

 

[Guest]

What carb are you running?

 

[Mike4130]

What carb are you running?

Factory, I know, I've heard these factory carbs are junk. Been looking at the Walbro 990. What are your thoughts on the carb cleaner?

 

[andyken]

sounds like a air leak..? Check the carb/intake bolts.

Have you run it for a while before this started?

I like the 990 carb [wish it had a choke] but covering the carb to choke it works for me.

 

[Mike4130]

Yeah, an air leak is what I'm leaning towards. I've been running the truck for a week now, 4-5 tanks through it so far...I will check to make sure the carb is secure. Thanks. I thought Walbro makes a carb with a choke? What aluminum manifold should I look into tall or short ?

 

[Guest]

The Walbro 668 has a choke.

Either intake is fine. I've used both and could not tell performance of any performance differences.

 

[Mike4130]

The Walbro 668 has a choke. Either intake is fine. I've used both and could not tell performance of any performance differences.

So why doesn't everyone run the 668? Is there a performance difference?

 

[Deluge]

The 668 is a bit laggy on the low end. The 990 doesn't have that issue.

 

[Guest]

Yeah, when the carb is transitioning from the low to high needle it has a slight lag.

 

[Mike4130]

Winner!

sounds like a air leak..? Check the carb/intake bolts.Have you run it for a while before this started?

I like the 990 carb [wish it had a choke] but covering the carb to choke it works for me.

The carb & manifold were loose. I haven't ran it yet but I'm pretty sure that this was causing the issue. Good call!

Thanks as always for all the help Andyken,RCDad & everyone else. I'd be scratching my head without great minds like yours.

 

[andyken]

I've heard that the stock intake can also warp, aluminum ones are not to much $.

 

[Mike4130]

I've heard that the stock intake can also warp, aluminum ones are not to much $.

I've already began looking into them. This one will work correct?

http://www.davesmotors.com/s.nl/it.A/id.4477/.f

 

[Ildy666]

That will work...

 

[Mike4130]

That will work...

Thanks. I will order 1 now.