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Discussion Starter #1
This is an early pre-TDM 345, number 46,302 made so I believe it's a 1997. It has 1400 hrs. New to me. I purchased it in running condition, it needed a massive cleaning and I made sure to protect the circuit board. The unit ran fine and I cut for about a half hour test. Then went I went back to start it, I turned the key to the first detent and it began cranking the engine even though I hadn't gone to the final detent where it would normally crank. If I pull the purple wire off the starter solenoid, the start disengages. If I pull the plug off the circuit board, the feed for the purple wire is hot. Based on some other forums I have read, it appeared to me that the crowd was say it was a bad circuit board and go buy a new one. That what I did at a cost of $200 Cdn including a new key ignition. I installed it, turned the key and thankfully the starter did not engage. I turned it to the starter position and then it made some weird buzzing sound and following that it is back to starting in the ON position instead of start position. Some folks have said that perhaps there is a short somewhere feeding 12V to the purple wire, but the board is sending that power as the connection is hot at the board with the plug pulled. It's getting power at the board, so I can only assume I've welded that starter relay closed again, but am unsure how. Another poster said it happens when the harness has a bad ground? I'm not exactly sure where the harness grounds, but the mower was starting just fine a day ago. I'm hesitant to pump more money into it and am wondering if it might make more sense to sell the liquid cooled engine to someone who needs one and just repower and rewire an air cooled vtwin into place.

Thoughts?

Much appreciated.
 

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The starter/solenoid combo is where I’m leaning, although there could be multiple other shorts, or a incorrect wiring hack.
 

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Discussion Starter #3
The starter/solenoid combo is where I’m leaning, although there could be multiple other shorts, or a incorrect wiring hack.
There are no wiring hacks, it's all original.

How would a starter/solenoid issue back feed power the circuit board?
 

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This is caused by a bad ground. Unfortunately what happened is you fried a diode on the circuit board. You will need to add a ground from engine to frame and then frame to battery. Then piggy back a ground wire from the circuit board plug to frame. If you don't get it all grounded and bonded it will quickly fry a new board.

Sent from my LGL52VL using Tapatalk
 

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Discussion Starter #5 (Edited)
This is caused by a bad ground. Unfortunately what happened is you fried a diode on the circuit board. You will need to add a ground from engine to frame and then frame to battery. Then piggy back a ground wire from the circuit board plug to frame. If you don't get it all grounded and bonded it will quickly fry a new board.

Sent from my LGL52VL using Tapatalk
Thank you, that is certainly what another poster had confirmed. I've attached a picture and the red pen is pointing to a black wire coming out of a plug closest to the dash. Would this be the correct wire to piggy back on to for ground? It's not the plug that has the purple solenoid wire in it - it's the plug with the smaller pins. Sorry about the pic being upside down, not sure why it's rotating when I upload it.

IMG-9890.JPG
 

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Discussion Starter #8
Yes.. Piggy back there and then do a resistance check. Less than an ohm and you should be good.

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I decided to do a little experiment last night and opened up the relay for the starter (I think). It was the relay that I could tap with the end of a screwdriver and get some response from the starter before it completely fried.

I figured if I could 1) add a ground as you mentioned, and then manually open/close the relay, I could prove out the theory by using the lead to the solenoid on the starter as my start key.

Sure enough, everything worked! Very happy. In fact, as this is a bit of a beater of a machine, I am considering just hardwiring the relay permanently and adding a momentary start switch into solenoid lead for starting. Seems like the $200 a new board will cost me would pay for a lot of fuel!

IMG-9895.JPG
 
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