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SEIA Farmer 
Bronze Level
Joined: 03 Apr 2019
Location: keota
Points: 49
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 Topic: WC Starting
Posted: 14 May 2023 at 6:12am |
After getting my engine rebuild issues solved on a '37 WC, now I'm trying to get it to start with the hand crank. It will bang right off with a pull start, but I can't get as much as a "pop" when hand cranking! The carb has been rebuilt, and it runs good when started. I think I have magneto issues. I got a "newly rebuilt" FBM mag online, but not sure of the quality of it. I took it apart, and put in some new parts that looked questionable, but I can't get it to perform on the tractor, like it does when in the bench vise! That was 3 years ago, so returning it is not an option. Now I can't get the impulse to "snap" with every crank revolution, so I think I need to investigate the impulse. I do have one from a parts tractor that was fairly "hot", so I might check it out to see if it will work. How is the best way to check a mag, without having a test stand, short of sending it off to a rebuild shop?
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Steve in NJ
Orange Level Access
Joined: 12 Sep 2009
Location: Andover, NJ
Points: 11992
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Posted: 14 May 2023 at 9:43am |
I'm not sure how you are holding it, but in order for an impulse to work every time, the Mag needs to be in it's upright position so the pawls can extend and catch the lock stud in order for the impulse spring to wind up. If holding the Mag sideways or on its side the pawls can't come out to the lock post. The pawls work by centrifugal force.
Also, Mags can lose their spark laying around or not in use for a while. The point contacts oxidize and get a moisture coating over them not allowing current to flow through the contacts. Usually, a little spritz of TV tuner cleaner or Brakekleen, and run a rag through the contacts will remove the oxidation and spark will return. Don't use a file on the contacts. That just removes the Cad plating which is on the contacts for corrosion resistance. Once removed, the points will always need cleaning every time you go to start the Tractor. Especially if the Tractor sits for long periods of time between uses.
Steve@B&B
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39'RC, 43'WC, 48'B, 49'G, 50'WF, 65 Big 10, 67'B-110, 75'716H, 2-620's, & a Motorhead wife
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DaveKamp
Orange Level Access
Joined: 12 Apr 2010
Location: LeClaire, Ia
Points: 6066
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Posted: 14 May 2023 at 10:39am |
Yeah, if you're not getting the CLACK of the impulser, that'll certainly cut down on your success with hand-cranking.
I'll 2nd Steve's notes, with one addendum... if it works well in a bench vise, and it does NOT work in a freshly rebuilt engine, I would look at the ground path of the freshly rebuilt, and see if mebbie a meticulous and lovely paint job might be a significant insulator, at least enough to prevent a significant amount of spark energy from making the round-trip.
You can easily test this, by applying a test lead from one plug's ground body to and unpainted exterior point of the magneto, and hand crank it...
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Ten Amendments, Ten Commandments, and one Golden Rule solve most every problem. Citrus hand-cleaner with Pumice does the rest.
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Fred in Pa
Orange Level
Joined: 13 Sep 2009
Location: Hanover Pa.
Points: 9210
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Posted: 14 May 2023 at 11:09am |
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Do you have a gasket between mag n mounting .Sometimes there is not enough space on drive to allow impulse to work .
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He who dies with the most toys is,
nonetheless ,still dead.
If all else fails ,Read all that is PRINTED.
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SEIA Farmer
Bronze Level
Joined: 03 Apr 2019
Location: keota
Points: 49
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Posted: 14 May 2023 at 11:27am |
Thanks for the info guys! Sounds like I need a new set of points because I always used an emery board nail file to shine them up! How is oxidation on the points any different than on the rotor and cap contacts? Avoiding setting around doesn't sound good because that's all it does! That would also nix the idea of having a spare setting around, ready to go, if need be! Is there some way to treat it to keep the oxidation to a minimum? BTW, the vent hole in the bottom of the cap is clear, so the moisture can get dried out, if need be. Yes, I always test it in the upright position, and for some reason, I'm only getting a "click" on every-other crank rotation, so I need to see if I can figure out what's up with that! The body of the mag is clean and void of any paint. I always use a gasket on the mag mount because I read once that it's more of a spacer to keep the lugs from binding in the mag drive. Does that gasket interfere with the ground? If so, it needs to ground through the mounting bolts, correct? Would a ground wire help? Looks like a good cleaning and inspection is in order! What kind of turn-around time could I expect if I were to send it off to get "freshened up"?
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AaronSEIA
Orange Level
Joined: 11 Sep 2009
Location: Mt Pleasant, IA
Points: 2571
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Posted: 15 May 2023 at 5:51am |
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If you sent it to Harveys in Galesburg, you'd have it back in a week or so.
AaronSEIA
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Les Kerf
Orange Level
Joined: 08 May 2020
Location: Idaho
Points: 1275
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Posted: 15 May 2023 at 1:14pm |
 SEIA Farmer wrote:
... I got a "newly rebuilt" FBM mag online... |
There are impulse mechanisms with different amounts of 'retard', having the wrong one will give you fits due to hard starting.
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