Cat carb help

[afroman]

my 1996 AC EXT 580 is running a little rough. I think i need to adjust the carbs. First question does anyone know the proper setting for the air mixture screw? is it 1 turn from full in?

Second question is i can get my hands on a carb sinc gage. are these easy to use? and does anyone have some hints?

Thanks

[Knotwood]

The idle air mixture screw can vary from to three turns out from a slightly seated position, and it only affects the idle to approx. 1/8 throttle opening. Most manufacturers set them about one to 1 and 1/2 turns out. If you are experiencing slow response off idle, it is more likely the low speed jets are slightly clogged, and they are only accessible taking off the bottom of the carb, and unscrewing them with a small but sturdy screwdriver. Clean out with a sewing needle and plenty of carburetor, brake cleaner spray and/or air.

The synchronizing of carbs is important, make sure the throttle slides reach WOT position at exactly the same time, you can usually use a finger to reach inside the carb throat for this, feel how each slide comes up, and adjust it with the screw and locknut on top where the cable enters. Work the throttle up and down several times to get it right. Idle is usually done with the synch tool, and if it is a flow type, you can easily see if one reads higher than another, adjustment on the side of the carb (big screw).

It helps to keep fresh plugs in, too, often slightly fouled plugs may look OK, but in fact short out while running.

[PERCHJR]

Hey afro, you could solve the problem and buy a fuelie!!! Just giving yah a hard time!!!

GOOD LUCK AND GOOD FISHING!!!

[afroman]

thanks for the help guys keep it comming. and what the hell is a fuelie?

[afroman]

oh ya and how does the sync tool work?

[lawdog]

fuel injected...

[sledhead]

If I'm not mistaken most cats in those years have sight windows on the side of the carb with an indent on the slide with a yeallow paint mark on them. Set the pilot air at 1 1/4 turns out for lihtly seated position, then loosen the trottle cables up, set the idle with a small drill bit by inserting into the front of the carb uder the slide, while tunring the idle screw in. once you have you don this then pull on the throttle until you see one of the yellow dots in the window. center it in the window, using a zip tie to hold the throttle in position, then turn the cable adjuster on the other card until the other yellow dot is centered. Once this is done the carbs will be in sync, release the throttle and chack you cable tension, should be about a credit card thickness maybe a little more. If not turn both cable adjusters out or in equal amounts until achieved. bing bam boom your done. If you don't have the windows it can be done by feel to, sync gages work well, but not really an exact thing they can be with in to pounds of pressure and work mint. Mostly keeps the throttle from hanging, and gives a more even throttle just past 1/4 to half throttle.

[Knotwood]

The flow types are a hand held unit, put it over the intake of each carb. Usually there is a spongy material to keep the fit snug, hold the gauge upright, too. You should set the meter level by opening or closing the adjustable baffle (mounted on the intake of the meter, like a restrictor/choke plate) and match the other carb by using your idle stop screw.

The mercury slide types attach to the intake manifold, behind the carb, by a spigot, often covered with a piece of rubber hose with one end closed-(don't know if yours has any, may need to drill and install them- this type is not common on sleds), they use vacuum to determine the amount of air demand. Match the amount of height on the upright gauge for each cylinder with the idle screw. They'll have hoses and often restrictors inline to keep the signal from overwhelming the gauge. If you are using mercury (there are solid rod types, too) be careful not to rev the eninge too far, so as not to suck any mercury into your engine.

I've also seen guys yank a plug wire off, look at the RPM's, then try the same process with the other cylinder- not as accurate and can foul plugs- make sure you keep the (loose)plug wire grounded while doing this, you don't want to buy any ignition parts due to stray voltages not having a place to go.

What kind of problems are you having with your machine?

[hanson]

afroman-

I'm just guessing you need a good carb cleaning to start with. When was the last time they were taken apart and cleaned? Then throw some new plugs in and good to go.

Easy & cheap to do. If that doesn't work, then I'd check out the above mentioned info. Very good stuff.

Hate to say it but throw on a compression gauge after that to see where you are at.

[rmh2o]

afroman I would clean your carbs again and replace fuel filter if you havnt already done so.When you cleaned them last time did you notice and remove and clean the small jet that is on the bottom of the carb next to the main jet?It is hard to see and requires a small straight screwdriver to remove.This is often overlooked and can cause problems.After I remove all the jets I take a can of carb cleaner and attach straw tube that comes with it and spray out all orifices.

[afroman]

thx for the advice i just cleaned the carbs and the thing runs good just think it idol a little rough. i have a print out of a how to make a home made carb sync gage and it sounds pritty easy. my carbs have a nipple on the outlet side and i should be able to install it there to balance them. what do ya think? i hope i have time to try this week.