Carb Question

[Fourrunner]

Noticed the other day that this rubber boot (Item 15 - Carb Accel Boot) was ripped and looked wet around it as well. Am having issues with the idle (when warm runs really rough). Could this torn boot cause this rough idle? Remember seeing a post a while back about someone having the same issue and solved some running issues.

http://www.sor.com/sor/cat042.tam?xax=31614

Had the carb rebuilt by Jim C and not sure if it was replaced. Would assume it wasn't by the looks of it.

 

[NocalFJ60]

I don't think that would cause a rough idle. That boot is in most carb rebuilt kits I believe.Think that boot is around the main plunger that lets gas into the bowl.

You have a vacuum guage? I would check your vacuum at the intake manifold. Running rough at idle could be a manifold leak along with other things.Check your timing?

 

[Fourrunner]

NorcalFJ60,

I have checked vacuum at idle. It runs at about 16mm Hg. The needle did jump between 15.5 to 16.5, not bad though. I need to spray around the manifold with carb cleaner and see if there is a leak. I also have brand new vacuum lines for it and may switch those out and see if it works. Any other ideas?

 

[schaats]

Sometimes, debris in bad gasoline block the idle passage in carburetor and cause rough idle. (My case)

Oh, Min Seok

 

[Fourrunner]

It has run about the same since Jim C rebuilt the carb. So I don't think it is debris.

 

[FJ40Jim]

There isn't a connection between the AP well (which the boot covers) and the idle circuit. If the idle is rough, it is usually a lean condition. Check for lean problem by shooting some Gumout spray carb cleaner (may not be available in the PRK) into the top of the carb when it is idling rough.

If idle picks up & smooths out when adding fuel (gumout), then mixture is lean.
If idle gets worse, then engine is rich.

LMK what you find.

 

[Fourrunner]

Hey Jim!

When you do rebuilds, don't you set the fuel/air mixture to factory settings?

 

[FJ40Jim]

Hey Jim!
When you do rebuilds, don't you set the fuel/air mixture to factory settings?

In your case, yes.

However, the A/F is affected by factors outside the carb, such as vacuum leaks, altitude, burning MTBE fuel, temperature....