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laney64

Ignition help on simplicity 738

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laney64
I have a 738 and it sat outside for 6 mnths and I just pulled it into my shop and tried to start it but the ignition switch had gone bad. So I replaced it and now it just burns up the coil and I went and installed a in line fuse and now it blows the fuse every time I turn the key on. The ignition switch is not a simplicity switch but a 2 pole switch. please help I am lost.

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DMedal
Hi, Scott- Welcome to our site. Please consider membership as the $10 gets you a lot of extra benefits and is the most cost effective thing you can get for your tractor. Specifically, it allows you to post pictures, which may be needed to diagnose your problem. I'm sure someone will correct me if I'm wrong, but looks like the 738 had a magneto stock, no external coil. Your machine has an external coil? can you trace out where this circuit goes? battery to ignition switch to fuse to coil? Here's what I find for a 738 schematic, but it sounds like yours isn't wired like this:


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PatRarick
Unless it's been converted to battery ignition, the 738 should be magneto ignition. Putting power to the magneto, even momentarily, will burn out the coil. If battery power is applied to the magneto, there will most likely be some power draw if the points are open, but if they're closed, it will be a dead short.

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DMedal
light dawns..... (thanks, Pat) the ignition switch died, and was replaced, now it burns coils? wiring fault. coil should connect to GROUND in "off" to kill motor. You've got it wired like automotive I think, where the coil is hooked to +12V in "run". That would give exactly the symptoms you described. I forgot how easy it is to do that error. Now to see what's left of your coil, Scott...

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AllisPhreak
I did exactly the same thing with my 12 HP Case/Ingersoll riding mower. Was trying to find the reason why I had no spark to the spark plug, installed brand new $43 Magneto. Still no spark, so installed a new ignition switch -- I figured that maybe that would work. Bad idea. Smoke, flames emanated from the magneto. Scratch one $43 magneto. You purchased and installed the wrong ignition switch. During PROPER operation, what the switch does is ground out that magneto when keyswitch is in the OFF position. This shuts the engine down. The keyswitch you installed quite likely had +12v directed to the magneto, rather than ground. Your keyswitch is wrong for your tractor. Make sure that the markings on the rear of any new switch match the markings on the old. IE : GND, L(ight), B(attery), etc. Did this help ?

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DMedal
Scott- I'm going to let someone else answer the part # question, you actually have several options, I believe. Try this to see if you have to buy a coil too: disconnect the wire from the coil. You know that's bad news anyway. Start it, but with a long screwdriver handy. If it runs ok or even sorta ok, your coil is ok. (whew) If you have no spark when cranking your coil is probably toast. Caution:You can't stop the engine with the switch anymore. Use the screwdriver (or anything else insulated) to pull the spark plug wire to shut it off. I'm not meaning you should by mowing with it without the kill switch. Do as I say, not as I do. :D -Don

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gregc
quote:
Originally posted by laney64
does anyone know how I can find out the simplicity part number for the ignition switch?
quote:
Originally posted by 4xbill
Go back to the club home page and enter your MFG no. in the manual search box and download the parts and/or operators manuals. I think my 738 is 990898

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