8N Carb - idle circuit mfg issue???

(reply to post at 13:56:08 09/14/14)

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(quoted from post at 00:50:45 09/16/14) Thanks for the insight. I went back through the carb again verifying every passage on that diagram are open and clean. Back to together now.

After I find a 6V battery, i'll see how it fairs (oh the suspense).

P.S. went to the local auto parts store - $110 for a poor quality 6V battery!!!! Hmmm where to get one of these?

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(quoted from post at 14:31:47 09/14/14) Could still be just a clog, because it does end more or less as a "blind" hole, in that it intersects with the fuel well surrounding the nozzle. Further more, it decreases in diameter near the fuel well.

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(quoted from post at 06:52:04 09/21/14)

(quoted from post at 14:31:47 09/14/14) Could still be just a clog, because it does end more or less as a "blind" hole, in that it intersects with the fuel well surrounding the nozzle. Further more, it decreases in diameter near the fuel well.

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truly a good pic
You should post it on every single MS carb thread that pops up.
Vertical tube with a bottleneck shape at the bottom,
sediment, rust scale and gravity says it HAS to clog sooner or later...

To the original poster.
before you throw the carb back on, check the throttle shaft bushing/seal carefully.
Working on a little JD with a similar MS carb.
I haven't went thru the carb yet, good runner,
but a slight lope at idle can't be adjusted out.
watching the governor rod at the carb, I thought I saw the slightest shake.
misted carb cleaner on the throttle plate shaft back there, and the lope went away.
It's pulling just enough air around the shaft to mess up the idle mixture a little. easy fix.
(95% of the tractors I get that have recent carb work, new gaskets, screws, etc.....that bushing hasn't been touched....)

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(quoted from post at 05:44:43 09/22/14) Ok the outcome:

Runs better than it ever did. Starts without chock and will idle at low rpm w/o choke.

Observations:
Lopy idle and perhaps an occasional electrical miss.
Idle mixture screws has some effect on idle speed - certainly will not richen it up to the point of black haze in the exhaust but will slow the speed down when too rich
Idle mixture screw only about 1.5 turns out is best running perhaps .5 turn out compared to highest rpm.
Idle mixture screw all the way in won't kill the engine - odd?
Not a very good transition from 400 rpm to 1000 rpm or so - not much response in the first portion of the throttle lever.

My points were pretty bad - only about 4yrs old but they had infinite resistance when closed. I ran a few passess of 600 grit paper between the contacts (both sides). This is interesting, even after the 600 grit, still no continuity with points closed. Run a piece of paper through them and would get about 0.3 to 0.4 Ohms resistance. Cleaned with IPA, then cleaned with paper, lost continuity. Repeated the 600 grit procedure then back to continuity. Are points that finicky? Is it hard to restore them - I bet they only had about 10 hours run time on them.

Running video is here: http://youtu.be/r3jjNmduyes

Thx - Paul

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(quoted from post at 23:06:37 09/21/14)

I would replace the points with some high quality ones! They corrode just siting around, especially if they are closed.

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(quoted from post at 23:06:37 09/21/14)

I would replace the points with some high quality ones! They corrode just siting around, especially if they are closed.

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