'49 8N 6v - another coil issue?

Replaced coil mid-2017 when it wouldn't re-start when hot ( new ignition kit also ). Fixed problem, ran fine rest of year. April 2018, after bush hogging for about 3 hours, started losing power. Within another 2
hours things really fell apart. Would almost die then catch and couldn't handle any load. Spent most of Summer working on it. I've got pretty low compression in the 70lb range, but it had the same readings in
2008 when I bought it. Used some MMO in the cylinders and ran it a few times. I do have a new fuel valve, line, and filter at the carb. New carb in 2008. Seems to run fine for about 10min ( I read some of Dell's
posts ) and then dies as if running out of gas. Not sure where gas tank vent is. No vent hole in my gas cap, but won't re-fire if I loosen cap. Have to wait about 1-2 hours and it pretty much starts right up. I've
checked fuel flow thru the carb w/ drain removed. Didn't do the 1-2min pint test, but it seems to be coming out pretty fast. Not really suspecting fuel flow at this point.

Could I be dealing with a coil yet again? I bought a $30 U.S. made coil last time. My 6v batt seems to be getting on the weak side ( 5yrs old ). Could a weak battery come into play? BTW... I did replace the ignition
switch a few weeks ago as well ( broke it removing the hood ).

As always, I appreciate any assistance.
 
Any engine with compression that low needs everything else to be 100% good in order to run. until that is fixed you will be chasing your tail trying to keep it running.
 
Unless you are unlucky and got a bad coil or you left the key on, chances are your coil is fine.

Check the battery per tip # 49. The number one cause of a weak spark is a weak battery.

Will your spark jump 1/4" in open air?

When is the last time you set the points and timing?
75 Tips
 
I did set points & timing when I replaced the coil last year. Replaced the condenser & points as well. Will test the battery this afternoon w/ a hydrometer and look at spark.

Thanks as always...
 
Three factors are required to start and run: Fuel, Spark, and Compression. The first two are usually the root cause problems on a non-starting/non-running tractor, but since you say you have low compression readings, can take that into account. First, you need to conduct some more problem solving and stop tossing new parts into the mix until you KNOW for sure the part is defective. How did you determine the coil was bad? How do you ?break? an ignition switch? What is a ?new ignition kit?? Do you mean a tune-up kit consisting of points, plugs, condenser, cap, rotor, and maybe new plug wires? It is pertinent that we know if you have a 6V/POS GND or a 12V/NEG GND system PLUS if it is a front-mount distributor or an angle mount unit. You say 6V BUT is it wired correctly? Yes, a good reliable brand battery is a key element in the electrical circuit no matter if 6V or 12V. Remove the battery and take it to your local starter/alternator shop to be tested under load on his test equipment. While he is testing the battery, you need to go thru the entire wiring system, verifying by a continuity tester/VOM set to that setting. Do not use an idiot test light ?those require power and you want to check static. Forget wire colors; most harnesses are not made to exact colors anyway. 99.98% of non-starting/non-running issues are due to poor/incorrect wiring jobs regardless if 6V or 12V. You say you have fuel flow thru the carb drain plug. There is a vent on the gas tank. It is on top of the dome of the tank. It takes less than a minute to blow out/clear but several hours to remove the tank from the hood. That isn?t your problem. Did you then next check for spark? Do you have a copy of ?75 Tips for N-Owners? by Bruce(VA)? Download a copy ?it?s free. Also download a copy of ?WIRING PICTOGRAMS BY JMOR? . You can get it at the *N-*T-*C ford tractor web site under HOW-TO?s/ELECTRICAL ?also for free. As usual, get out your essential manuals for reference ?I&T F-04, 39-53 MPC, and Operator?s Manual. Finally, my advice is to save your $$$ and forget about using any of the ?snake-oil? products sold. They don?t do anything but thin out the gas and/or oil. MMO is one of the biggest jokes out there. What?s the ?mystery???? ALL of these products use plain petroleum distillates ?MINERAL SPIRITS, as their main (about 98%) ingredient. You can get the results from paint thinner and charcoal lighter fluid ?they are exactly 100% the same thing. Your tractor, your $$$, do what you want but do it right the first time.

FORD N-SERIES TRACTOR FUEL TANK w/ VENT & CARB:
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FORD 8N TRACTOR ESSENTIAL OWNER/OPERATOR/PARTS & SERVICE MANUALS:
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Tim *PloughNman* Daley(MI)
 
Remove the point plate in the distributor and check the wire that bolts to the side of the distributor.I had this problem and found that the insulation around the wire was brittle and cracked and missing in spots and causing it to go to ground.
 
The battery was definitely bad after 6 years. Hydrometer showed 2 marginal and 1 bad cell after charging overnight. Tractor at least ran for 30 min before I shut it down. Still kind of rough w/ a good bit of popping in the exhaust. Going to check spark this weekend. BTW... I pulled the plug wires one at a time while running at a high idle. I literally had NO engine reaction. Never tried this before, but I expected something...
 

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