Runaway diesel

Big Bri · Jul 12, 2018

I just bought a used grasshopper 722dt6 with a 3 cylinder diesel. Engine only has 350 hrs. The first two times I cut my yard she performed flawless. Yesterday while cutting the mower would slow down while going up hills to the point of almost dying. (Motor would slow down) I called grasshopper today while at work and they said to
1, change filters
2, drain the fuel tank and start with new fuel and give it a try.
that didn稚 help
next
if that didn稚 work I was told to take off the supply line out of the tank and check for leaks ( put thumb on one end and blow) no leaks there.
so I put It back together and added a little power service clear diesel to see if it might clean an injector
well when I started the mower it went full tilt and I had to pull the air cleaner and shove my shirt into the intake to stop it.
i have since drained the tank and added new diesel from a different store and she still wants to run away.
any ideas?
Thanks for the help

Billrog · Jul 12, 2018

Injection pump fuel rod is stuck. A least that's my guess from my experience.

mercdv · Jul 12, 2018

Having experienced a stuck fuel rack myself that would be the first thing I checked. Take the governor housing off and see if the fuel rack control rod freely moves in and out. It should move pretty much effortlessly. If it doesn't, you have a stuck fuel rack. As long as it is just a gummed up rack and not stuck because of a mechanical part failure, it will be easy to free with a little patience and a good penetrating oil. It could be a stuck governor too but you will figure that out as soon as you remove the governor housing. I am just assuming you already checked the throttle cable.

Big Bri · Jul 12, 2018

I’ve never messed with an injector pump so this will a new venture for me. Will look at it tomorrow

Big Bri · Jul 12, 2018

I did look at the throttle cable and governor and both seem to be working fine. Thanks

mercdv · Jul 13, 2018

Big Bri said:
I’ve never messed with an injector pump so this will a new venture for me. Will look at it tomorrow

I hadn't either until this year. I had always been told to never touch them because our shop required a certified tech to touch them. Of course, that was until thepumpguysc told me I could fix my own as long as I didn't touch the wrong things. He walked me through the process on here. If you find the rod doesn't move well at all, I can post my write up on what I did to fix mine after listening to thepumpguysc's advice.

thepumpguysc · Jul 13, 2018

Thanks mercdv.. It kinda depends on which type of injection pump he has.. it might be easier than yours to un-stick.
IF you could post a pic of the pump & engine, that would be GREAT..
I know it might be "tricky" to put a pic on the site, so I'll send you my email address..
THAT WAY.. if you have it on your phone, you can send it quicker..

Big Bri · Jul 13, 2018

thepumpguysc said:
Thanks mercdv.. It kinda depends on which type of injection pump he has.. it might be easier than yours to un-stick.
IF you could post a pic of the pump & engine, that would be GREAT..
I know it might be "tricky" to put a pic on the site, so I'll send you my email address..
THAT WAY.. if you have it on your phone, you can send it quicker..

Here are the pics as requested. I messed around with it a little this morning before going to work. The in the video you can see movement is limited. Thanks again