Stall with chipper - L3800

[utkdoc]

I have an L3800 that has about 300 hours on it currently. I have used varying types of implements without issues- post hole, rototiller, finish mower w/o issue. I recently got a Woodmaxx wm-8h hydraulic wood chipper (19hp requirement - L3800 has 31 PTO hp) and have been experiencing engine stall while using. The stall happens seemingly random - a few minutes after engaging all the way up to 20 minutes of use. Chipper flywheel rpm hardly changes when chipping- maybe 20-40 rpm drop with the larger diameter wood I have chipped. It handles the load fine otherwise.

I am really not sure what is causing the problem. It does not appear from anything getting jammed as it will stall w/o using the feed and also when feeding small, 1/2" diameter branches. There isn't much warning - the engine RPMs suddenly drop and the engine is off in about 2-3 seconds. The chipper flywheel stops within about 5 seconds which is very bad I know! When i restart the tractor, there is no apparent issue. Re-engage PTO, everything spins up normally - there is no "catch" or "grab" when it stalls nor starts back up. No indication of anything hanging on the chipper side. The chipper belts that drive the pumps all appear fine. Hydro fluid in the chipper is filled to spec. No reason to suspect air in the system. I am running at 540 pto engine RPM.

I am going to try swapping out my fuel filter as that could be the issue but again I have not seen this issue any other time except when I have broken shear pins with the post hole digger. The new chipper appears to be operating fine but that being the newest component is obviously the first place to look. I will admit I have really not used any PTO driven implement for this long at one time- post hole digger gets the job done in a minute, the tiller is used about 50' each pass then off until the next pass. The finish mower runs obviously longer periods but seems to be very light engine load. Any thoughts?


Video Link -- Shot from underneath pulley system of the chipper

New video · Wednesday, Apr 6, 2022 🎬

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[mcfarmall]

Sounds like more of a shutdown than a stall. Maybe a glitchy seat switch.

 

[utkdoc]

Sounds like more of a shutdown than a stall. Maybe a glitchy seat switch.

Yea I think you're right - it's a full shutdown. My seat switch is "fixed" so it won't shut off when I dismount. It's hard to gauge if its a tractor problem or implement problem because something is stopping both rather abruptly.
IF was a fuel issue, would the kinetic energy of the flywheel make that a drawn out stall or more of a quick cut off as is in my case?
It worries me because that 200lb flywheel is coming to a halt in about 10 seconds which is a huge amount of energy going backwards into the tractor. Something is going to give

edit: i will double check seat switch today though - that is a good thought

another thought - wouldn't an abrupt system halt break the shear pin on the PTO shaft it the problem was arising from the chipper? This should not be the case if the issue is on the tractor side I would imagine

 

[85Hokie]

I'm with mcfarmall - the problem seems to be in the safety switches

What happens if you run the PTO with the chipper and DO not feed anything ............ does it ever slow down?

 

[Tughill Tom]

PTO switch out of adjustment?
Does' the input drive shaft have a clutch? Maybe out of adjustment too?

 

[North Idaho Wolfman]

Check the fuel solenoid for overheating.
Could also be the relay that runs that solenoid that is failing.

 

[utkdoc]

Thanks everyone for the input!

Updates---
Changed fuel filter- some debris but not bad
Seat switch zip tie working great- does not appear to falsely activate

I'm with mcfarmall - the problem seems to be in the safety switches

What happens if you run the PTO with the chipper and DO not feed anything ............ does it ever slow down?

Had this idea too -- tried it after it shut down twice today. Could not reproduce after running at PTO RPM for 10 minutes BUT it has happened once ~ 10s after feeding some small twigs

Also tried this without anything attached to PTO - no shutdowns - seems usually heavy load related phenomenon

Check the fuel solenoid for overheating.
Could also be the relay that runs that solenoid that is failing.

It does seem to work just fine initially (at least 30 mins) then it starts happening repeatedly. I took a video of this occurring. You can hear the chipping juust finish then it occurs. The higher pitched whine is the flywheel slowing - I hear the same sound when I decrease RPM to shut it down normally.
The start / stop behavior I have not seen happen in the 8-10 other times this has occurred.

I'll go ahead and order a replacement relay just incase.
How would I go about checking that solenoid? Voltage across it with multimeter? or probably just use a clamp meter?

One other data point which may relate to above also -- after the engine shuts off, the "click" you hear when you activate the glow plugs (aka turn key to left - I'm guessing it's a relay?) occurs twice in about a 3 second time window after about a minute if I don't go up to the tractor to turn the key off. In other words, if I touch nothing.

Video Link -- Shot from underneath pulley system of the chipper - I don't think can glean anything from this though

New video · Wednesday, Apr 6, 2022 🎬

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[North Idaho Wolfman]

Yep it's an electrical issue, the tractor is shutting down.
Feel the solenoid and see if it's hot.

You can also remove the solenoid (tape over the hole), run it and see if the problem stops, betting it will.
It's intermittent so metering it probably won't tell you much.

Could also be something as simple as bad grounds or bad connections at the solenoid or relay.

 

[utkdoc]

I found the solenoid- I'll go out and see if it heats up. Is it as big of a deal as I think it is allowing this shut down?

Looks like would be an easy direct swap - only two bolts. What is the purpose of that solenoid if it will run without being present? Diesel is totally new to me so looking to learn

 

[Henro]

I found the solenoid- I'll go out and see if it heats up. Is it as big of a deal as I think it is allowing this shut down?

Looks like would be an easy direct swap - only two bolts. What is the purpose of that solenoid if it will run without being present? Diesel is totally new to me so looking to learn

The solenoid either enables starting the tractor, or causes it to shut down. Otherwise, it would not be there.

So removing it would eliminate it from the spurious shutdown issue, if after removing it the tractor started and ran normally.

Simply removing it does not guarantee it is the issue I do not think, as if it is used for shutdown, it still could be getting a signal to shutdown from something else. BUT it is a starting point towards isolating the issue.

 

[utkdoc]

Probably a silly question, but if I remove the solenoid and turn the engine on, will I be able to shut it back off via key or is there another mechanism that will shut it down?

It did not seem to be hot to the touch at all with finishing up my chipping pile - no more warm than surrounding components

 

[Henro]

Probably a silly question, but if I remove the solenoid and turn the engine on, will I be able to shut it back off via key or is there another mechanism that will shut it down?

I would think you would need to put the solenoid back in place to shut down the tractor. Probably just holding it in place by hand (with the key in the off position) for a couple seconds would be good enough.

If you would try this, as NWI Wolfman suggested, it might also be wise to cover the opening with a piece of tape to keep dirt out during your test.