Toro MX5050 no start

[jcbenson01]

I’m in need of help, PLEASE!

I have a 3 year old Toro MX5050 with a Koehler 7000 series. It recently started dying on me and not wanting to restart. I found and printed a wiring diagram and began trying to trouble shoot. The wiring diagram seems pretty accurate except a little incomplete. The mower appears to have an oil psi sender which I assume kills ignition of it sees low oil. That part is not anywhere on the diagram. I’ve also read that it may have a meecury tip switch which I wouldn’t know where it was or what it looks like..... I disconnected the brake control module to test the pins and upon plugging it back in to test the last two wires (output), just for kicks I decided to hit the key and viola, she started. So I cleaned the connector and put some dielectric grease in it and thought maybe it was just a bad connection since it started multiple times with no issue.

Then, It happened again about 5 min into mowing. So I pushed it back in the garage and started poking around again. Disconnected a connector at the engine and it looked terribly dirty so again, I cleaned it and voila, it started!.... only to die a short time later once I started mowing.


I’m struggling on this one. It’s just a lawnmower and I know I’m overlooking something. A couple of other clues:

On at least one other occasion, I disconnected the brake module and let it sit for a minute or two and after reconnecting it started.

I seem to remember the first time it happened, actuating the arms back and forth and it tried to crank. Almost like the safety switch was bad. But I could hear the brake module each time I activated the arms.... so I know it’s not the actual safety switch.

Although it is an intermittent issue, I’m thinking hard as to what happened each time it died and as I recall, every time it has died when I was coming to a stop. It seems like one common denominator is shutting the pto switch off. But I also recall the very last time pulling up to the house to run in and grab something and it died right when I shifted my weight out of the seat to stand up (which very well may have included shutting the pto off at the exact same time as I will usually rev it down and click the pto switch off as I stand up and step off).

I’ve tested and tested and tested. I bypassed the seat switch too just for kicks even though each time I test it I find it’s working perfectly.

I can jump the solenoid and get it to crank but no start. When it is in a no crank position, the solenoid has power going to both blue and green wires which are the smaller (command) terminals on the solenoid. But to crank, the green wire needs to be grounded. I can manually ground the green wire coming from the pto clutch that goes to the solenoid and then the key will successfully crank the mower but still no start. Likewise, I can ground the terminal the green wire feeds at the solenoid and produce cranking but no starting. That circuit starts at the key switch which feeds the circuit via pink wire as follows: pink wire is split into two wires via a jumper and goes into either side at pto switch. After pto switch, one side of the switch goes to pto clutch and then on to the brake module and solenoid. The other side of the pto switch goes into the brake module only.

 

[jcbenson01]

 

[mechanic mark]

https://www.toro.com/en/parts?SearchText=74770&SelectedFilterByOption=equipment

LOCATE YOUR SERIAL NUMBER, then manual & troubleshooting section in manual

 

[jcbenson01]

Thanks, Mechanic Mark but if that’s what I think it is, I have that “troubleshooting” portion on my manual and it wasn’t very helpful. But I’ll take another look just to make sure.

But I’m still desperately seeking help.

Here is an update as of today:

Bypassed the seat switch, charged the battery the last couple days and load tested (tested good). Yesterday it wouldn’t crank. Walked in today, though, and it started. So I mowed and made sure not to disingage the pto or move the handles to park. Mowed for an hour and a half fine. When I got done I tried to duplicate the issue and get a better feel for what triggers it.
When stopped, the mower will cut ignition if you put handles in park (regardless of whether the PTO is engaged). It won’t die if just one handle is in park but when both are placed in park, it dies/loses ignition exactly 2 seconds after handles are put into park. Likewise, with pto engaged, if you put in park, the mower wil die, but if you shift levers back into neutral really quick and disengage pto, mower will continue running.

When I shut it off ultimately, the battery was dead like it’s not charging. The mower was freshly charged prior to mowing and was not shut off the entire time mowing. Seems very odd that the battery isn’t charging while the mower is running, yet the mower ran just fine the entire time.

Please HELP!!

 

[bertsmobile1]

First thing is to check the charging system.
So recharge the battery.
Read the battery voltage
the voltage rectifier + to battery -
Regulator + to ground ( crank case is fine )
Regulator body to battery +

All of these should be the same +/- 0.5V
Start the engine and do the same.
Turn on the PTO and do the same
With the engine running above also measure the AC voltage between the AC terminals on both of the above.

Let us know what you find

An alternator can be providing power to the mower & the PTO but not recharging the battery depending upon how the mower is wired.
A mower can generally run for a long time on a single charge without the alternator running.