Spark plugs fouling

to30man

Member
The 8n I am working on is giving me a fit. Changed the oil a few weeks back and it ran great while letting
it warm up. After adding oil and started back up it ran a couple minutes and started skipping bad and cut
off. Gas started leaking out of the bottom of the carburetor. I worked on the carb and could never get it
to stop leaking so bought a new one and installed today. The tractor started up and run less than a minute
and started skipping and smoking blackish smoke this time and before it was blue. Removed spark plugs and
they had some sludge on them and black I cleaned them and the tractor started up and less than a minute it
started skipping. I can clean them and it will run only a couple minutes and then back black again. The
sludge was only on them the first time. After I removed them the first time a turned the engine over a
couple times and it blower a little stuff out. Not sure were given here any help would be appreciated
thanks
 
To30man......cuppla things about the 8N, theres 2-kinds of dizzys. The weird 4-nipple front mount with points=0.015 and the more normal 5-nipple side mount with points=0.025. Both use the same sparkies, recommend AutoLite 437's gapped 0.025. You kenn count nipples, kent you? Yer complaint of SKIPPING and FLOODING, recommend you learn how to adjust yer carbie. Set yer down-pointing MAINJET to 2-turns and LEAVITT!!! Adjust yer side-pointing idlemix fer FASTEST idle, NOT SMOOTHEST idle. Understand the difference? Shud be about 1/8-1/4 turn. Final thang, even NEW carbies, need to be checked out. The interal FLOAT (0.25-in) kenn hang up on the side of the carbie. The float valve needs to be seated really tite, and the needle needs to be swirled in the float valve polishing everythang up. And lastly, the needle needs to be clipped to the float with a little wire thangy (technical term, thangy) Don't fergitt, yer carbie is gravity fed and sometimes the front top of the gastank vent gitts clogged by mud-dobbers. Donna mucka 'round, just unscrew the capple 1-notch. Iff'n that fixes thangs, gitt a VENTED capple fer 600-series. Simple, eh? ........HTH, the amazed Dell
 
Dell's new business? Naw they ain't "sparkies". Lol.
a154956.jpg
 

How much oil did you add? You can easily rebuild these old Marvel-Schebler carbs, my first choice, as some new aftermarket carbs are junk. Gas leaking out -where from the bottom drain plug or thru the air intake? May just have a dirty unit and a simple rebuild is in order. A stuck float can cause gas leaking too. The fuel inlet line -the brass elbow on carb - has an inline fine mesh screen filter and often these get plugged. Remove fuel line, clean off screen and reinstall. Is it a M/S TSX 33 or a M/S TSX-241 carb? If you want to part with ol done, email me...

M/S TSX 241 and TSX 33 carb -note diff in Main jet adjustment screws:
9N951003.jpg


TSX 241 and later carb have a brass MFG ID TAG with model number and date of manufacture:
9N951006.jpg
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Tim *PloughNman* Daley(MI-USA)​
 
Two carbs, same symptoms. I would look elsewhere.
Once you get it figured out, your new carb will still need adjusting.

Are you running it with the air cleaner hooked up?
If so, have you tried running it with it unhooked?

Do you have access to an adjustable gap spark tester?
They're less than $10 at the local auto parts store here.

Depending on what type of new carb you got, you may want
to keep your old one. Some of the new ones don't last long.
Others are hard to get parts for when they need a rebuild.
 
"TSX 241 and later carb have a brass MFG ID TAG "

So did some of the TSX-33's. Had quite a few of them here.

47003.jpg


Normally they are stamped like this in the same spot like this.

47004.jpg
 
What does the gap spark tester do. I removed the air filter can and cleaned and replaced the oil in it
today the steel wool looking screen was clean all but about an inch or so around the bottom. Also installed
new plugs. It got to late for me to try and start today I hope to get time tomorrow after work. Is there
any way the oil change could have started my problem or just my unlucky timing
 
As a quick test, just leave the air cleaner hose off the carb.

An adjustable gap spark tester lets you see if your ignition
system is producing enough voltage to reliably fire an engine.
Swiped this picture off the internet.
The markings are approximate voltage outputs in KV.

47005.jpg
 

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