Royce , GB or others. Need carb help

HCooke · May 27, 2017

Have a 49 8N that has been running rough lately. Replaced the points last fall for a no start situation. Was not inclined to do a full tune up at that time because of weather. Today I replace the plugs, regapped the points (which may have been just slightly closed) and rebuilt the carb. Carb looked clean but I found the idle mixture screw was broken. Replaced the top half of the carb with one off the shelf. Tractor runs fine, starts without choke, idles well and has full power. Question -- How can I remove the broken segment of the idle screw???

Dell (WA) · May 27, 2017

Cookie.........yer N-carbie is castiron. Yer idlemix screw is BRASS. They actually make "reverse thread" drill bits that will un-screw yer jambed idlemix screw. I wouldn't hand-hold the drill motor, drill press is the way to go.
.......the amazed Dell

Royse · May 27, 2017

This might be overly obvious, but are you sure that tip is still
in the carb? If its not you should be able run a wire through.

If it is stuck in there, you might get it out with a small left hand
drill bit as Dell suggested. Unfortunately there's not a good,
clear passage to get behind it and push.

One thing I might try before the drill is to boil the top half in
water and Dawn dish soap to clean the crud out. If there are
no threads still holding the tip, it may fall right out when you
tap the top against a block of wood after boiling. I'd try while
warm, but you can safely tap a little harder after it cools too.

GB in MT. · May 27, 2017

(quoted from post at 13:41:29 05/27/17) Have a 49 8N that has been running rough lately. Replaced the points last fall for a no start situation. Was not inclined to do a full tune up at that time because of weather. Today I replace the plugs, regapped the points (which may have been just slightly closed) and rebuilt the carb. Carb looked clean but I found the idle mixture screw was broken. Replaced the top half of the carb with one off the shelf. Tractor runs fine, starts without choke, idles well and has full power. Question -- How can I remove the broken segment of the idle screw???

b:270d610535][i:270d610535]

HC;
How in the heck did ya break THAT off????? :shock:
Never mind.......NO threds on the needle point SO....DON't use a reverse drill on it!!!!!! That will just spin the needle end!!!!
Hold the throttle body upside down.....stick a sewing needle up into the hole and while you move the sewing needle around in there.......(loosely) If you are lucky, the end that is stuck in there.........Should just fall out!!!!!!!!!!!!!!!!!!!!TADA. (you HOPE)

That adj. needle goes in a 45deg turn to adj. air/fuel mix.
What ever it takes to un-lodge it!!!!!

Don' stick something in there that will bugger up the threds.!!!!

Gary......BTDT!![/i:270d610535][/b:270d610535]

HCooke · May 27, 2017

"This might be overly obvious, but are you sure that tip is still

in the carb?"

Yes the tip is still there and I think there may be one thread still holding it in. I can see it in there but it would not show up in a
photo. Will try your ideas. Fortunately I have several MS carbs around that I have cannibalized from time to time, so I have a couple of
tops. I would like to get that out as that was a good carb at one time. I doubt that was my rough running issue.

Royse · May 27, 2017

I figured you had already checked that but had to ask.

The nice part about mild heat, as in boiling, is that it doesn't melt
anything and that the dis-similar metals heat and cool at different
rates. It can be very helpful at times and is non-destructive.

I have had to use a torch on some, but if you have to go that
route, be prepared to replace it if things go South.

Tim PloughNman Daley RIP · May 27, 2017

Harold-
I'm just spit ballin' here, but if it is still hanging on by a thread or two, and since it is brass, try soaking in PB BLASTER or a good carb cleaner, for a day or three first. Take a screwdriver or small chisel punch and whack a slot on the top then try and unscrew out. A light whack at first may be enough to force the remains down into the hole a bit then fall out. Keep us informed on your solution...I'm currently soaking two carbs that are so frozen up with crud they look like they were buried for 50 years and very well may have been. I can't wait to see what the insides look like and may run into similar problems breaking needle jets and such...

Tim *PloughNman* Daley(MI)

Jock(OR) · May 27, 2017

If I have to drill out something like that, I machine a drill guide that just slips into the threaded area and has a hole appropriate to what you are trying to do. In your case, the hole would be just large enough for the smallest easy-out that would work in the necked-down needle section. I have a small lathe, so I have the luxury of making these sort of tools!

Drilling out is the last resort.

Royce , GB or others. Need carb help

HCooke

Well-known Member

Dell (WA)

Well-known Member

Royse

Well-known Member

GB in MT.

Well-known Member

HCooke

Well-known Member

Royse

Well-known Member

Tim PloughNman Daley RIP

Well-known Member

Jock(OR)

Member

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