engaging pto makes my 312-8 engine die

[JCD 80]

I've run into a strange problem, started up the 312-8 and went to mow but as I engaged the pto it started bogging down and would die if I kept pushing the pto lever forward.

 

It doesn't die when the pto first engages, the belt turns and so do the blades but if I push it forward more than a couple of inches it kills the motor.

 

No smell from the belt or any burned areas that I can see.

 

I decided to try and drop the deck, haven't done it before, dropped the bar from the attach o matic but then it started to rain so I struggled to get the bar reattached, had to use 2 jacks to hold it in place while I locked it in.

 

When I did that I noticed the belt seemed very loose so I tightened it up but the deck looked funny, the front was higher than the back, when I went to lift the deck it was apparent that something had become detached or broke because my lift arm is loose.  

 

I can see a chain moving up and down but it's not connected to anything anymore.

 

Anyone know what has happened and how to fix what I messed up?

 

Thanks, Jim

[wallfish 18,083]

The safety switches are shutting down the ignition. The PTO switch is connected to the seat switch so the PTO can not be operated without someone sitting in the seat.

You will need to diagnose where the problem is in the wiring or a switch. Search the files and download the manual for your tractor and it will have the wiring diagram in it. 

[davem1111 2,159]

Assuming you were in the seat and the seat switch was engaged, as Wallfish stated might be the problem, it sounds to me like your lift arm became detached from the chain that goes up to the rocker arm, and possibly dropped down to interfere with the turning of the center pulley.  I guess if your PTO clutch is good and your belt isn't slipping, that could be enough drag to bog down the engine.  

 

Let's see what the experts here say - I'm not one of them 

 

[gwest_ca-(File Mod) 11,472]

Make sure you get the correct wiring diagram. Let us know if you need help.

The ignition systems used on the 312-8 changed and improper testing can release the magic smoke in the wiring.

 

When attaching a mower to the tractor there is a forked tab that must be installed correctly at the mid-hitch for everything else to fit. The mower deck operator manual will have this illustrated.

[JCD 80]

As far as I can tell all the safety switches have been removed.  

 

Is there anything else that could cause the pto engagement to kill the engine?

 

It literally sounds like it is bogging down and cutting out, once it starts to bog I can pull the lever back and the engine will roar back to life.

 

Seems that a safety switch would just stop the engine not allow it to keep running by pulling the pto lever back and I can do this repeatedly, ease it forward, start to bog, pull it back and running 

 

I plan to drop the deck when I get back up to the tractor and see if the blades are hitting anything but I know they are moving when I first engage the pto as I can hear it and see air and some grass blowing out from the edge of the deck.

[wallfish 18,083]

Maybe a blown bearing in the bell in the housing???

The easiest fastest way to determine if the issue is at the deck or not is to take the belt off the PTO and engage it.

[JCD 80]

Thank you Wallfish, I didn't think of that.

 

I'll do that first thing when I head up Tue.

 

Jim

[ohiofarmer 3,372]

Look down under the engagement lever for the fuse block. ( If there is one) I jF that problem before and blew grass clippings and dust out of the fuse block and sprayed a bit of penetrating oil in the fuse block and it worked again

.

    Love my 314 but not a fan of the Christmas tree lights and excessive safety switches 

 

[953 nut 59,890]

First you need to get your mower deck attached properly so you can check out the belt movement by hand with the engine turned off. This manual will guide you through the proper alignment for mounting. There could be a bad bearing in PTO bell, the mule drive, or on the deck.

 

[Brockport Bill 1,933]

Disconnect the mule belt to pto then engage pto would be good starting point for diagnosis to determine cause and effect?...,

Also try other suggestions mentioned by others..also could be frozen mule pulleys causing stress resistance beyond what engine can power when you engage pto lever 

[JCD 80]

Ok got up to VA today and checked the tractor,  it's not the pto, I removed the belt and when I engaged the pto it didn't bog down at all and kept running, I tried several time to be sure.

 

It's not the idlers up front they spin in both directions freely.

 

I flipped up the deck and found dried build up of grass that had been there way longer than I have owned the tractor.

 

I scraped it all clear, but the spindles look like they were packed with grass, I cleared out what I could, reassembled everything and tried it out, pto didn't bog down.

 

I mowed about a fifty foot strip got into some slightly heavier grass and the engine started to die, pulled the pto and revved back up and ran fine, I tried engaging the pto again and bogged and almost died.

 

I had to leave at that point but tried engaging the pto in the shed (dirt floor) no bogging, blades turned fine.

 

I'm wondering about the deck spindles,  could grass be packed up inside causing resistance?  using hand pressure I can spin the blades and get about 1 complete rotation before they stop, should I rebuild the spindles or get new ones or does that not sound like the problem.

 

Also my blades are horribly dull.

 

Thanks,  Jim

[8ntruck 7,824]

Sharp blades do reduce the mowing load on the engine - especially in heavy grass.

[JCD 80]

Could be it, although when it first started happening I was sitting still not mowing,  I'll sharpen the blades first thing next time I go up.

 

Thanks,  Jim

[953 nut 59,890]

2 hours ago, JCD said:

could grass be packed up inside causing resistance? 

I have had some baler twine wrap itself around the spindle and about stop the blades from turning, heavy grass and weeds could do that too.

[8ntruck 7,824]

2 hours ago, JCD said:

Could be it, although when it first started happening I was sitting still not mowing,  I'll sharpen the blades first thing next time I go up.

 

Thanks,  Jim

Dull blades are just part of the problem.  The grass you found wrapped around the spindles were most of the problem.

 

Sharp blades will also chop the grass up into smaller pieces a o it is less likely to get wrapped around the spindles. 

[JCD 80]

I think I have identified the problem,  I watched a lot of you tube videos and found one where the guy was replacing a spindle, while not a wheel horse, once he replaced the spindle and got the blade on he used one finger to spin the blade and it rotated about 9 times when I spun mine with hand force it rotated 1 time.

 

I'm quite sure the spindle bearings are going out or have lost their grease so I'm going to get new spindle bearings, clean out all the grass gunk, sharpen the blades and I'm quite sure the problem will be solved.

 

I really appreciate all the suggestions and tips and diagrams from you guys,  I hope one day I'll know enough to help the new guys on the forum as you all have helped me.

 

I'll let you know how it turns out.

 

Thanks,  Jim

[JCD 80]

I was wrong, got up to VA and dropped the deck did a very good cleaning of the deck top and bottom, got all the accumulated grass out and the blades now spin freely.

 

I checked all the pulleys and idlers, rechecked the pto and everything was good so instead of sharpening the blades I put it all back together to see if it would work, it did not.

 

I was checking everything I could think of, gas tank cap off and on, oil level and while I had the hood up and tried the pto I found the problem.  I post my new questions in the engine section.

 

Jim