1988 John Deere Hydro 175 - Engine stalls when I engage the blades

[SquatchLife]

Mine had a little yellow button I had to push in order for the mower to stay running in reverse. It was to the left of steering wheel. I thought the yellow lever to engage the mower was a manual engagement, not electric. Certainly felt manual. I guess different year???
Do all pulleys spin freely when not engaged? If the engagement is manual like I thought mine was, check that pulley.

Everything was different back in the late 80s.

It’s a toggle switch that you have to lift and push up to engage the blades. The lights are on a push-pull knob. There are 3 different belts under the mower. One is drivetrain, one is to engage the deck and one is to engage the blades. No foot gas pedal, only a foot brake, forward and reverse is on a pull lever to the right of the seat. To lift the mow deck there’s a 2.5 foot lever sticking out next to my left leg with a thumb button on the top. To change the mow height I have to manually remove bolts and cotter pins and lower or raise it before I mow.

I feel like I’m mowing with the millennium falcon. There’s a different button or pull, or button or lever for every little thing.

None of that is a complaint by the way. I love that every little thing is manual. Despite not actually mowing right now it’s a sweet little rig.

 

[Mtsoxfan]

Everything was different back in the late 80s.

It’s a toggle switch that you have to lift and push up to engage the blades. The lights are on a push-pull knob. There are 3 different belts under the mower. One is drivetrain, one is to engage the deck and one is to engage the blades. No foot gas pedal, only a foot brake, forward and reverse is on a pull lever to the right of the seat. To lift the mow deck there’s a 2.5 foot lever sticking out next to my left leg with a thumb button on the top. To change the mow height I have to manually remove bolts and cotter pins and lower or raise it before I mow.

I feel like I’m mowing with the millennium falcon. There’s a different button or pull, or button or lever for every little thing.

None of that is a complaint by the way. I love that every little thing is manual. Despite not actually mowing right now it’s a sweet little rig.

Sorry, mine was a few years newer. You had me laughing though when you were describing the tractor. Brought back memories of a junker I used as a kid in early 70's. Good luck...
Not to be a wise ass, but you should be able to find something for a couple hundred...

 

[Richard001]

Do you have a wiring diagram for you machine ?

 

[aa2tn]

My Scag zero turn throws belts too. I think I've figure it out, but it's too early in the mowing season to be sure. It only happens when I first start to mow with it, but once it's been mowing for a while, it works properly.

New blades made it better, but didn't fix the problem.

I changed the type of grease that I was using on the spindles, and that helped, but it still happened. I bought new belts and that helped, but it still happened. I bought new springs that control the tension, and it hasn't happened since.

In my case, I think that everything was causing it, and by just replacing one thing, it got better, but it didn't completely solve the problem.

If it happens again, I'm thinking that I need to find a soft start switch to turn on the PTO. I don't even know if such a thing exists, but that's what I think I might need.

Try starting the PTO at half throttle if you don't already, then bring it up to full throttle.

 

[Donjackofall]

Are there other specifics that you may have overlooked.
Is the engine one cylinder or two cylinders? If it is a two cylinder you may have an issue where it is only running on one cylinder and when you engage the deck belt the engine is unable to power it fully and cannot move the governor properly, causing it to die. Have you checked the engine compression? Low compression from a leaking head gasket or valve leakage from wear will also lower the power level causing the engine to die when the blades are engaged.
Remove the belt and try engaging the blade lever like it would normally work and see if the engine still dies. If it dies without the belt installed, especially if it dies quickly after barely lifting the belt engaging lever it is most likely the engaging arm safety switch. Your symptoms are indicative of a safety switch issue at the engaging lever, however a low power condition will have the same end result. Read the spark plug(s) and if it/they are reading as fouled or if one looks good and the other is carbon or oil fouled you most likely have a low power condition.
Do a compression test to determine any low compression issues (leaking or blown head gaskets, worn rings, worn valve seats etc.)
Under normal operation when engaging the deck belt, if the engine is at operating speed the engine will temporarily bog but the engine governor will shift the carburetor causing the throttle plate to open which in turn feeds more fuel into the engine to overcome the sudden load induced upon belt engagement. The engine experiences a dramatic load when engagement takes place and must have sufficient power to overcome the induced load. Also, if you can access the magneto unplug the ground wire and test the mower under load. If the safety circuit is "killing" the engine the engine will run properly under engagement. The safety circuit grounds the magneto when working properly. If the mower works properly with the magneto ground wire disconnected, you have some sort of electrical condition that is grounding the magneto upon engaging the deck drive lever. If you unplug the magneto ground wire the engine will not turn off. You will have to remove the plug wire (shock hazard) to kill the engine. If you are not highly competent in repair, you should leave that step to an experienced repair person.
ALWAYS PLAN YOUR STRATEGY, ANTICIPATE YOUR NEXT STEPS BEFORE TAKING ANY RISKS ASSOCIATED WITH POWER EQUIPMENT REPAIRS. PROCEED AT YOUR OWN RISK. IT IS REQUIRED THAT YOU KNOW WHAT YOU ARE DOING BEFORE ATTEMPTING ANY OF THESE STEPS. i HOPE THIS HELPS

 

[boatmoter]

Hey all,

Literally bought the tractor yesterday for $150. It was running and mowing very well when I bought it. Fast forward 24 hours and it mowed for about 10 minutes before it threw the blade belt. Got it back on and mowed for another 10 minutes when it threw the belt again. Got it back on, went to engage the blades and the mower stalled. I checked the belt to see if it was too tight and it spins freely by hand. I checked the blades themselves and they spin freely by hand. Checked the blade engagement toggle in the dash and one of the connectors was not plugged in. So I unplugged it, cleaned it up, got all the connectors plugged in and lined up and the mower still stalls when I try to engage the blades.

Should I start with replacing the toggle switch or should I look elsewhere on the mower first? Or should I be looking somewhere else entirely?

remove the belt and grab hold of the blade and try rocking it side to side, could be bearings worn and keeping a pulley cocked to one side. that will throw a belt, keeps the belt alignment off

 

[Gord Baker]

Is this what your mower deck looks like ?


View attachment 3217737

If so, then I would start by looking at the support that holds the idler tenson pully and the pulley bearings. I'm guessing that they are worn and allowing the pully not to be aligned with the belt path.

Also make sure that the tension spring is doing it's job.

Richard

The top pulley is what powers the Mower Deck. Check all adjustments to be sure ist is correctly mounted. If that Pulley turns true and freely without wobble, Check the Belt
Size and clutch Pulley of the mower. Put the wiring back the way it was. Check Seat switch . Be sure to put a Deflector on the end of the deck.

 

[kioti28527]

Hey all,

Literally bought the tractor yesterday for $150. It was running and mowing very well when I bought it. Fast forward 24 hours and it mowed for about 10 minutes before it threw the blade belt. Got it back on and mowed for another 10 minutes when it threw the belt again. Got it back on, went to engage the blades and the mower stalled. I checked the belt to see if it was too tight and it spins freely by hand. I checked the blades themselves and they spin freely by hand. Checked the blade engagement toggle in the dash and one of the connectors was not plugged in. So I unplugged it, cleaned it up, got all the connectors plugged in and lined up and the mower still stalls when I try to engage the blades.

Should I start with replacing the toggle switch or should I look elsewhere on the mower first? Or should I be looking somewhere else entirely?

I have lots of sweetgum trees and every year i get one of the spikey balls stuck in a pulley and throws the belt,look at every pulley,and it sounds like you need a new battery

 

[kmesr9]

If it is like turned the key off I would suspect a safety switch is the culprit. I am not sure how many switches there are on that tractor though.

Does it have a switch on the seat for operator presence? If yes I would check that and then look for more. Hopefully someone more familiar with that model will chime in with other things to check.

That and the reverse safety switch was what I was thinking.

 

[Edstir]

I found after market belts may run a little larger and when they stretch or get older they may start to get thrown. It could be only a half inch bigger and cause trouble. I put mine back on and it doesn't immediately fall off again but I know it's time for a new belt. When new my mower got 8 years on the belt. Now 3 or 4 years. I learned about sizing investigating on the internet. I'm a believer on size.