Ditch Witch 3700DD Deutz Diesel Hand Throttle problem

[Bruce C]

I sell a lot of trenchers I find at auction. I currently have two 3700DDs with a common problem. I've seen this on other Deutz diesel powered Ditch Witch trenchers.

When I move the hand throttle to Faster, there may be no response for a minute or more. This is a rod control, so it's not a cable problem [see pic].

Strangely, at times, I can operate the lever to raise the trencher boom and the extra load on the engine gets the throttle to start responding.

 

[fibersol]

I have the same problem, did anyone find a solution?

 

[thepumpguysc]

Check your fuel hoses if they’re rubber..
AND.. check your supply/feed pump or get an electric one..
There’s no reason u should be waiting THAT LONG for the rpm to rise..
I’m taking an educated guess here, U have the single cylinder injection pumps, yes.??
If ur waiting that long, either the supply pump isn’t keeping up with demand OR..u have a sticking control rack that drives/actuates all the pumps..
OR.. u have 1 pump that’s holding up the rest..??
There’s a “timing plug” that can be removed that u use to lock the rack when removing and installing the pumps..
THAT PLUG will give a direct access to the rack.. remove the plug, start the engine, and using a pocket screwdriver “flick” the rack to check the movement of the control rack and rpm’s..
If it moves and the rpm’s go up and stays up before coming down slowly.. ur on the right path..

 

[fibersol]

Check your fuel hoses if they’re rubber..
AND.. check your supply/feed pump or get an electric one..
There’s no reason u should be waiting THAT LONG for the rpm to rise..
I’m taking an educated guess here, U have the single cylinder injection pumps, yes.??
If ur waiting that long, either the supply pump isn’t keeping up with demand OR..u have a sticking control rack that drives/actuates all the pumps..
OR.. u have 1 pump that’s holding up the rest..??
There’s a “timing plug” that can be removed that u use to lock the rack when removing and installing the pumps..
THAT PLUG will give a direct access to the rack.. remove the plug, start the engine, and using a pocket screwdriver “flick” the rack to check the movement of the control rack and rpm’s..
If it moves and the rpm’s go up and stays up before coming down slowly.. ur on the right path..

I understand what you are saying, but the thing is if I spray some starting spray on the air intake, the rpms go up and stay that way for a while. Would that eliminate a faulty pump issue or fuel problem as the reason?

 

[funwithfuel]

Follow thepumpguysc guidance. Determine if your engine is more responsive using the screw driver. Beyond that, if you open the oil fill cap, look down , you should see a stout little spring attached to the governor yoke. If that's damaged or stretched, you have compromised throttle control.