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Discussion Starter #1
My 8N has started sputtering and almost stalling out when it has to pull an implement. Took out our single row cultivator today and it worked great for a few passes, then started losing power until it wouldn't pull at all without almost dying. I checked the easy things....cleaned sediment out of glass bowl and checked air intake. Seemed clean. I know I don't have my plug wires crossed, because it's been running fine. So: is this issue my carburator needing a rebuild, or possibly a fouled plug??? Help! :?
 

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Make sure you have a decent flow of fuel right into the carbie and that it doesn't weaken out after 10 minutes. (if it does, then you have a partial block,) If that's ok check your condensor in the distributor.
 

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condensor 'open' failure will result in burnt points.. if points ain't burnt.. it ain't a condensor failure. ( points can burn for other reasons.. like too close a gap.. or crud on them ).

condensor 'short' fialure results in loss of spark.. pretty much like turning key off... not loss of power.

I'd for sure check fuel flow thru carb.. i'd also run the main needle in and then back out to where it was ( count turns )... then check your spark. might have a key switch with contacts becoming marginal.. or some other electrical issue.. ( worn coil is possible due to thermal damage.. more common on the front mounts.. though 50-70 yr old cylindrical coils will show their age.. they are not as good as the newer oil potted ones.. ).

If spark is good and stays good.. then go to fuel... one thing you can do on a ms carb is remove the bowl drain, turn gass off, remove main needle and fuel elbow and give a few hi power blasts of carb claner int he holes ( watch eyes ).. and make sure something simple isn't lodged in there.

post back.. we can get her going.
 

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Another thing to check is the fuel inlet to the sediment bowl, if there is an obstruction the fuel can't flow fast enough, also make sure that the fuel ine isn't close to the block or exhaust, causing the fuel to boil and creating a lean condition.
 

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Discussion Starter #5
Thanks guys! Points looks good. Have fuel flow thru carb...I removed plug at bottom and fuel ran out, although I'm not sure what volume of flow I'm looking for. Gonna try the cleaner sprayed thru the main needle hole this afternoon. Hopefully one of these fix it. I do feel like it's worse as the tractor warms up. Could that be the coil??? That might make sense in that you mentioned thermal issues with it....
 

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the cab bottom should pee a penil sized stream into a jar untill the fuel tank is empty.

thermal issues can happen on an old coil.. especially the dry potted cylidrical ones.. and at any age on the tar and epoxy potted square ones... switches with bad contacts add resistance and build heat.. which adds resistance.. etc.. etc..
 

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I do feel like it's worse as the tractor warms up. Could that be the coil???
It could be the coil breaking down under heat as it gets hot, if it's real hot too touch the coil is on the way out.
Sometimes a cracked inlet manifold will let the side down, running good when its cold, but as soon as it gets hot, the cracks open leaning your mixture right down. I'm thinking its more fuel or carburettor.
 

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Discussion Starter #8
Well, I pulled the main needle on the carb yesterday and gave it a good shot of cleaner and let some fuel run thru it for a bit. Definitely helped. I'm still going to check out my coil next time I use it and see how hot it's getting. Just don't feel like it's got the power it had when we were plowing last month. Thanks!!!
 

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How about the tank vent. The vaccum in the tank can cause poor fuel flow. Easy to test , put the tractor under a load until it starts to loose power and open the fuel cap. If there seem to be a vaccum holding the cap and the tractor starts to run better then the vent is pluged. Its been a long time since I had a N but I think the tank is vented and not the cap. I always check the easy things first.....mike
 

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what does thespark look like when it feels weak. if it's still blue.. it's not spark.

also ensur ethe advance mech is freemoving..
 
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