Thermoquad Whistling...

Rebuilt a 9811S for someone and it is whistling when the throttle is depressed just a little then stops again if it's depressed more. What would cause this? Anyone have this happen to them before? It's quit obnoxious. Other than the whistling at say 1000-1200 RPM it runs great!

Wiggle the primary shaft by hand and see if the tone changes.

Randy

Well couldn't get the tone to change but does seem to be an awful lot of slop in it. Are these fixable?

How much slop? ... only fix is a new base or bushings in that one.

pretty sloppy! Where do I get bushings?

Put a dial-indicator on it. TALK to a machine shop in your area.

Will Do.

Whistling is not likely the throttle shafts, check to see if there are two air holes inside the choke housing toward the front. That is where the whistling is comming from.

Or the whistling could be coming from the air bleeds. I drilled my air bleeds out on my thermoquad and after that my carb started whistling too!! Check to make sure they are good and clean. You'll have to take off 2 small covers on the top of the carb to expose them.

mine whistles at a certain idle rpm, shafts are tight, i have the choke removed, but if i put the air cleaner on, cant hear it. Might be just one of those things The real trick is tuneing it without A/F meter.

Thanks for the help everyone! I narrowed the whistling down to inside the primary housing. Not the air bleeds inside the housing either as I plugged them with my fingers and if I cover the primary housing inlet with a towel it gets quieter so looks like I'm gonna have to rebush the shafts... unless there's something else I should check inside the primary housing???

The two holes I am refering to are not small air bleeds. I am guessing .100 inch.

Look closely, staight back from the front two top fasteners. There is not a problem but they will wistle.

Are you running a thin carb-to-intake gasket? I've seen cases where guys didn't have the carb tightened down quite enough & it sucked air past the gasket. Kind of like the comb & tissue paper thing

If your referring to the two holes inside front of the air horn... Yes I checked them by plugging them with two fingers. I am running a thin 4 hole gasket but I always make sure I tighten carb down in steps to about 3000 ft. lbs... okay maybe 25. I picked up some bronze bushings at the local true value in town. I'll cut them to size and stick them in the deep freeze till I have time to install them. Like I've said I've taken the truck to town a couple of times already on test drives and it performs flawlessly other than the whistle.

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mine whistles at a certain idle rpm, shafts are tight, i have the choke removed, but if i put the air cleaner on, cant hear it. Might be just one of those things The real trick is tuneing it without A/F meter.

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I ran a TQ for years on the GTX, they will whistle at certain throttle openings.

Most of the time you don't hear it unless you have an open air cleaner.