Grasshopper 721D stalls out

Jsin673

Forum Newbie
Joined
May 29, 2020
Threads
1
Messages
2
I have a grasshopper 721D that started stalling out this summer. It started where it would run for about 10-20 minutes before dying. Now it immediately shuts off when cranked. I'm not a mechanical person, I also inherited this lawnmower and would like to attempt fixing it myself to learn about it. I've recently changed the fuel filter and bled the fuel lines. Any tips are appreciated. Its also a diesel engine (wasn't sure if all 721D mowers were)
 

Rivets

Lawn Royalty
Joined
Mar 11, 2012
Threads
55
Messages
14,757
Please post the model and serial numbers for your unit so the diesel guys have a better idea of what you have.
 

cpurvis

Lawn Addict
Joined
Aug 25, 2015
Threads
21
Messages
2,256
Another member had the same problem recently. In his case, the problem was a dirty fuel tank causing a blocked fuel line.

 

Jsin673

Forum Newbie
Joined
May 29, 2020
Threads
1
Messages
2
I was reading about that, going to check that tonight. I ended up getting it cranking right and had no clue what I did. It seemed to have a lot less power though. Then all of a sudden yesterday it started cutting off again when cranked
 

gsim

Well-Known Member
Joined
Oct 20, 2018
Threads
5
Messages
100
I have GH diesel, Kubota. Was dying after startup and turned out I removed and re-seated 30 amp inline fuse to fuel solenoid. Fuel solenoid is next to starter on my mower. Figured the fuse contacts and the fuse holder contacts were just oxidized, a lot like a battery terminals can get. So I applied very, very light film of vaseline petroleum jelly to the fuse contacts. The trouble never came back. I have heard from another GH diesel mower owner that if you have a powerfold deck, the misroswitch beneath the plastic deck height spacers can cause engine to die if the deck is not firmly down tight against that switch.
 

arto_wa

Forum Newbie
Joined
May 25, 2020
Threads
0
Messages
9
It sounds like the fuel solenoid is not holding the fuel on.

I have had that happen during cold weather startup (we need to mow during winter here!), when the battery voltage is marginal but still enough to start the engine!
Speeding up the engine to fast idle (increase the alternator output) is one way to overcome a temporary issue like that.

Check the fuel solenoid for proper operation.
 
Top