What size screw on fuel shutoff knob?

timsch

Member
I have a TSC branded fuel shutoff that's been on the 8N for about 10 hours of use. Yesterday I lost the round knob that goes onto the square ended shaft while using the tractor.

I have a couple of old bodies that I took the shaft and retainer screw from, but both screws were slightly larger and didn't fit.

Anyone know what size screw this TSC shutoff uses? The major diameter of the threads on the screws from the old ones was around .130", so this other is slightly smaller.

Next time, I'll take that screw out and put some loctite on it.
 
I don't know the screw size but I did experience the same problem and lost the knob. I've bought several shutoffs since then and found that all had not been tightened. As I too have saved old shutoffs I use parts and pieces as needed.
 
" Next time, ....."

I'd suggest that next time, you get a good quality sediment bowl from this site or nnalert's.

The odd size screw is indicative of the quality of the entire part, made in "The Land of Almost Right" and imported by a company w/ no concept of quality control.

BTW, standard gaskets & screens rarely fit those bowls either.

An OEM bowl is on the left in the pic. The other 3 came off of newly purchased 8N's & were replaced w/ OEM bowls.
sedimentbowlsbrassfittings001.jpg

75 Tips
 
First replacement shut off I bought was from this site and after many times tightening the screw I finally lost the knob.
I tried knob from old one but was different style.
When I messed that replacement up from too many shut offs with pliers replaced with it again and again lost that knob.
On the third replacement I red lock-tited that sucker in place. Hasn't come loose since (so far).
Thus I suggest once right screw is found Lock-tite that thing in place.
 

The best lock washer would be an external toothed lock washer.
I didn't have one in my collection but so far so good. My Jube came with no knob so I made one in 2014. Found a washer in my can of carb bits that had a rectangular hole.

I picked up a new bowl assembly but it sits on a shelf for now cause this one is doing fine if not opened all the way. The knob on the new one has a tight screw but the darn knob is still sloppy on the shaft. My homemade one has no free play when starting to turn it. If I replace the assembly I'm going to stay with my own wheel.
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I believe the correct size of screw is 8-32...and yes, todays parts require a dab of Loctite on that screw when putting one on if you don't want it vibrating off. Don't worry about getting back off -you won't ever need to remove again. While you're at it, if stem leaks, replace with a new valve assembly as those rubber gaskets get pinched and I've seen some that are just cheap vinyl and not OIL and GAS resistant...stem is cheaper than whole new sediment bowl assembly too.

SEDVAL03.jpg

SEDVAL01.jpg

SEDVAL02.jpg


Tim *PloughNman* Daley(MI)
 
Thanks for all of the replies folks. I'll head to the local HW store and pick up a 3mm & 8-32 and hope for the best. Loctite will be used.
 

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