Thread size for fuel screw

[MadDog69]

What is the thread size for the fuel mixture screw? I want to get a tap to clean out the threads, I removed an old alloy screw and am installing a new brass one from JD Jetting and it feels really tight and I want to clean out the treads, I think the alloy one may have left some material behind.

Thanks,

Jake

[grayracer513]

You should be able to measure the thread diameter of the new screw easily enough. After that, it's safe to assume it's an ISO thread. I can check one tonight if I remember. If I don't post it here, send me a PM to remind me of it.

[grayracer513]

Well, my metric thread gauge has gone for a walk, but what it looks like is an M6x0.75 fine thread. Double check it to be safe.

[William1]

Alright gray, you got me to drag my sorry butt out to the shop and actually measure a fuel screw.

0.5 X 6 mm but the fit did not seem perfect to my bad eyes. A .6 was def. wrong as was a .4

[grayracer513]

Alright gray, you got me to drag my sorry butt out to the shop and actually measure a fuel screw.

0.5 X 6 mm but the fit did not seem perfect to my bad eyes. A .6 was def. wrong as was a .4

I was thinking it looked more like a 0.5 pitch than an 0.75, but that would make it a "special" thread (not that it couldn't be). Using a magnifier and calipers to gauge the pitch, it did look like about 0.5, but the 36 TPI gauge was pretty close, too.

I think you may be right. M6x0.5. Tough to find a tap, most likely.

[MadDog69]

Thanks everybody, I might just live with it being a little tight, better than too loose! ?

Jake