Another Turf Tiger blowing PTO FUSES

skm

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Most of this post will be copied from my "first time user" post, from yesterday. I didn't feel that post would get the exposure that it needs to get me the help that I need.

This post concerns a STT61V w/35 hp Briggs, with about 1000 hours use.
Presently, I am having the blown fuse problem. Don't really know where to start, but I AM asking for assistance. Fuse holders were mentioned as correcting the problem in several cases. Replaced the fuse holders today. No luck! By the way, the problem is PTO related. First fuse blew and the blade stopped. Did not have a 20A fuse so I put in a 30A, knowing that is not proper. Mowed for about 2.5 hours before second fuse blew. This killed the mower. Replaced second fuse and drove mower to the shop. Indications that I have observed: (1). When PTO is engaged, ammeter drops to full discharge; then returns to about -5A. With the clutch unplugged, PTO switch energized, ammeter remains at zero. (2). PTO off, engine running, battery reads about 14.5VDC (no AC). PTO engaged, battery reads about 11.5VDC. (3). With clutch unplugged, PTO off or on, ohm meter read infinity to ground. Clutch resistance is approximately 2.6 ohm. (4). 12VDC across a 2.6 ohm coil (according to Ohm's law) should draw about 4.6 amps . Where is the rest of the current going? Last, but not least. The is no continuity to ground from the clutch side of the plug with it disconnected. Sorry I was so long winded, but knew no other way to cover it all. Thanks for your patience.

It appears, to me, that the clutch coil is good (and not shorted). Also the variation in battery voltage indicates a functioning voltage regulator. If the regulator/generator could maintain higher voltage/current, then the fuse would blow sooner. I hate to buy many expensive, non-returnable parts that do not fix the problem. Any assistance would be greatly appreciated.

Sam
 

Luffydog

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Check the battery not running = 12.48dc or now crank it up and check it = should be 13 to 14dc. If not you have a charging problem or blown fuse. First thing on these is always make sure you have a good ground. Look on the clutch it should have some numbers on it like gt 2.5-gt5 what does your have. Also under the key switch panel Check the yellow wire they get burnt and they stop charging. I am leaning if it's charging and if your readings are correct the clutch is going bad.
 

skm

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Thanks for the reply. The resistance of the PTO coil was good when I first checked it. Straight wired it to the battery for about 20 minutes and "cooked" the clutch. Resistance dropped to about .9 ohms and current went to about 24 amps. Replaced PTO clutch. No further problems.
 
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