No Idle after long WOT runs

[Barrman]

I can run the Whistler around town or for runs less than 50 miles at any speed I want and it will idle great at all times. I get on the road and run 2200-2400 rpm for an hour or two and it won't idle when I slow down. I have to go 2 clicks out on the hand throttle to hold 800 rpm. If I keep going, it gets gradually worse and top end power kind of goes away some.

I made a speed run of 130 miles Tuesday. The idle problem started after 40 miles. The last 15 miles of the trip I had trouble holding 45 mph. When we got to where we were going, (hooking onto a grain truck to drag home.) I had to use 3 clicks to keep it running. It surged some and died afer a few minutes. I just turned everything off and worked on tow bar hook ups for the next 30 minutes. It fired right up when I tried it and ran great with perfect idle and no hand throttle.

I have changed out the primary fuel filter twice now. I have not changed out the secondary filters. That will happen on Friday, maybe Saturday.

Besides filters, does anybody have any suggestions?

Thanks.

 

[doghead]

Does it start right back up? Is it hard to start when cold? I have one that stalls at idle as you described as well as starts hard and fires right back up after stalling(if you just wait a few seconds). I figure a New hydraulic head is in order for mine.

 

[gimpyrobb]

Tim your problem has been asked before and I think the others said to replace the O ring on the top of the hydraulic head. Lets see if someone who's been there chimes in.

 

[Barrman]

I replaced both secondary filters today and they were really full of crud. It didn't start any easier, still need 3 clicks to start it hot or cold. It did go down the road pretty good, but it did that before.

Yes, it has only started once with no hand throttle help and that was the very first time I started the truck. It has has WMO of some ratio in it ever since, so that could be part of my problem also.