How to check ZT 1644 for electrical problem?

[prangster]

Hello! I'm new to the forum and haven't seen an answer to my problem. The wires to the clutch got mangled the other day and the motor stopped dead. No signs of life at all when I attempted a restart. I cut out the bad wires and replaced with a jumper so that is fixed. I'm thinking that the wires shorted and kicked the automatic breaker which has not reset. Question: Where is the breaker and how do I test? If bad can I bypass while waiting for the replacement part? If the breaker checks out how do I test the various safety cut offs? Is there something I'm missing? Thanks for your reply!

Simplicity ZT 1644 hydro
Tractor: pkg #1693472
serial #00715
mfg #1693473

 

[Rivets]

Go to this website and use model number 1693477. You should be able to get a manual and wiring diagram for a unit the same as your's.

Lawn Tractor Manuals | Riding Mower Manual | Simplicity Mowers

 

[prangster]

Go to this website and use model number 1693477. You should be able to get a manual and wiring diagram for a unit the same as your's.

Lawn Tractor Manuals | Riding Mower Manual | Simplicity Mowers

Thanks! My mower is apparently too old to be listed there, but I did some snooping around on the Partstree site and I have a good idea what the breaker looks like now. Tomorrow I'll jump the breaker and see if the electrical system will come to life. I've been noticing that the safety shut offs for the seat and the PTO clutch are two-wired so I should probably be able to jump them each in turn if the breaker isn't the problem. Actually, if I can find my VOM that would be even easier. I enjoy shade tree tinkering but the grass is growing like mad and I need to get on it. The wildflowers were so pretty this year that I left them alone but now they are so tall I will likely have to hit them twice. The 44" deck has three blades which gives a nice cut but it's not much good for stuff over a foot and a half. I mow several acres of yard and "pasture" and this is the first problem I've had. It's been a good mower and since it doesn't have a cup holder it's good that I can drive it with one hand leaving the other free for my adult beverage

 

[prangster]

OK. more data.

Using my ohmeter and electrical schematics off the web I've determined there is a problem with the PTO switch involving the same wire that goes to the magneto. I assume that the safety cut offs interrupt this wire when a safety device is triggered although I don't really understand exactly how. In any case, before I start ordering parts, could someone check my reasoning please? I can hotwire the starter and start the engine. When I release the parking brake the engine dies. When I engage the PTO switch the engine dies. The two wires coming off the clutch show an open circuit. If I test the same two wires coming off the PTO switch they show closed when the switch is disengaged and open when the switch is engaged. Am I correct in thinking the PTO switch is the source of my troubles or is there something I have overlooked? Thanks so much for your reply.

PS Is there a way to bypass the switch or at least the magneto cutoff portion? My grass is growing at an alarming rate!

 

[Rivets]

Could be the PTO switch but I would like you to test the seat safety switch first with your VOM. Check the switch with no pressure on the switch and then again with pressure. Some of these switches are NO and some are NC. Your's should be NC.

Look at this manual starting on page 51. This should be your model, even though they do not list it.

http://bsintek.basco.com/BriggsDocumentDisplay/jgEGGP_duI0tG5ERl7mRgtLvBCd6.pdf

 

[prangster]

Could be the PTO switch but I would like you to test the seat safety switch first with your VOM. Check the switch with no pressure on the switch and then again with pressure. Some of these switches are NO and some are NC. Your's should be NC.

Look at this manual starting on page 51. This should be your model, even though they do not list it.

http://bsintek.basco.com/BriggsDocumentDisplay/jgEGGP_duI0tG5ERl7mRgtLvBCd6.pdf

Seat pressure switch checks out. NC when unoccupied, NO when pressure applied. I have not tried it with the engine running although I was sitting in it when I checked the PTO switch and parking brake with the engine running. Are we getting warm? I notice that the seat switch is not wired directly to the red/black magneto wire as are the PTO switch and the brake switch, although .... aha! Now I see how it works. This is fun. Ain't understanding mellow?!

 

[prangster]

Seat pressure switch checks out. NC when unoccupied, NO when pressure applied. I have not tried it with the engine running although I was sitting in it when I checked the PTO switch and parking brake with the engine running. Are we getting warm? I notice that the seat switch is not wired directly to the red/black magneto wire as are the PTO switch and the brake switch, although .... aha! Now I see how it works. This is fun. Ain't understanding mellow?!

Hmmm New PTO switch but still no life. Is it OK that the clutch itself shows an open circuit? That seems wrong somehow. I'm not schooled in reading schematics but I would expect some kind of resistance there. No? Remember the cause of all this was the mangling of the clutch wires which surely must have shorted although I found no signs of burning or melting of the insulation. I really don't want to buy a new clutch on the off chance it is the problem.

 

[Rivets]

I'm sorry to say this, but if you cannot understand the schematic, then you will have to take the unit in to a mechanic to solve this problem. I'm sure that the problem is in the safety switch system, but will not be able to help you, because you will not understand what I am trying to tell you.

 

[prangster]

I'm sorry to say this, but if you cannot understand the schematic, then you will have to take the unit in to a mechanic to solve this problem. I'm sure that the problem is in the safety switch system, but will not be able to help you, because you will not understand what I am trying to tell you.

That's OK. I decided to bypass the safety circuit by going straight from the ignition switch to the magneto. I suppose it's a rolling death trap now but it cuts like a champ again. Occam's razor and all that. Thanks for your help.