Engine Idle issues

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, and others.
M

Mike4130

Well-Known Member
Messages
191
Reaction score
0
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?
 
Last edited by a moderator:
RCDAD said:
What carb are you running?
Click to expand...
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?
 
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.
 
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 ?
 
The Walbro 668 has a choke.

Either intake is fine. I've used both and could not tell performance of any performance differences.
 
RCDAD said:
The Walbro 668 has a choke. Either intake is fine. I've used both and could not tell performance of any performance differences.
Click to expand...
So why doesn't everyone run the 668? Is there a performance difference?
 
Yeah, when the carb is transitioning from the low to high needle it has a slight lag.
 
Winner!

andyken said:
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.
Click to expand...
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.
 
Back
Top