Mutifuel WOT

[will-m]

70 continental multi fuel. Went to start after sitting for a week or two for some brake work and a flame heater delete and it’s going straight to 2000 + rpm’s. Did a bunch of searching/reading and so far have pulled the fuel shutoff cover and the actual rod itself. Checked and lubed the little sleeve under the hydraulic head and the fuel rod and both seem to be moving freely. Reassembled fuel rod, sitting around 7 o’clock with truck off, moves smoothly toward the firewall and snaps back freely. Pulled the bypassed FDC to look down inside and nothing seems obviously wrong. No broken springs and the governor weights seem ok from what I can see. Pulled the piece of fuel return line I used to replace the t for the flame heater and everything looks good. After all this tried starting the truck again and it started then stalled. Then started and idled normal for a few seconds and stalled again. Then four or five times would start and then stall right out. Then would just crank and was acting like it was getting no fuel at all. Checked to confirm intank pump was running. Let it sit for maybe 5 min and tried again and truck started and went straight to 2000 rpm’s before I pulled the shutdown. Wondering if anyone has any suggestions on where to look next? Was thinking about pulling the governor cover to try to get a better look in there. Also have a new hydraulic head that I’ve been holding onto just in case but am kinda at a loss as to where to go now. Any suggestions appreciated. Thanks in advance

 

[rustystud]

70 continental multi fuel. Went to start after sitting for a week or two for some brake work and a flame heater delete and it’s going straight to 2000 + rpm’s. Did a bunch of searching/reading and so far have pulled the fuel shutoff cover and the actual rod itself. Checked and lubed the little sleeve under the hydraulic head and the fuel rod and both seem to be moving freely. Reassembled fuel rod, sitting around 7 o’clock with truck off, moves smoothly toward the firewall and snaps back freely. Pulled the bypassed FDC to look down inside and nothing seems obviously wrong. No broken springs and the governor weights seem ok from what I can see. Pulled the piece of fuel return line I used to replace the t for the flame heater and everything looks good. After all this tried starting the truck again and it started then stalled. Then started and idled normal for a few seconds and stalled again. Then four or five times would start and then stall right out. Then would just crank and was acting like it was getting no fuel at all. Checked to confirm intank pump was running. Let it sit for maybe 5 min and tried again and truck started and went straight to 2000 rpm’s before I pulled the shutdown. Wondering if anyone has any suggestions on where to look next? Was thinking about pulling the governor cover to try to get a better look in there. Also have a new hydraulic head that I’ve been holding onto just in case but am kinda at a loss as to where to go now. Any suggestions appreciated. Thanks in advance

So every part of the injection pump controls are moving freely ? No sticking throttle or foot control or anything like that ?
Then I would check the turbo outlet for leaking oil. I know this sounds kinda silly, but if your leaking engine oil form the turbo it could cause a hard start and even a wide open throttle response. That is what caught my attention when you said it would not run right, then went total full throttle.
It still is more than likely something in the fuel system, but for grins and giggles just check the turbo.

 

[will-m]

So every part of the injection pump controls are moving freely ? No sticking throttle or foot control or anything like that ?
Then I would check the turbo outlet for leaking oil. I know this sounds kinda silly, but if your leaking engine oil form the turbo it could cause a hard start and even a wide open throttle response. That is what caught my attention when you said it would not run right, then went total full throttle.
It still is more than likely something in the fuel system, but for grins and giggles just check the turbo.

Everything seems to be moving freely. Fuel shutoff lever, the linkage under the FDC, and the throttle linkage. Throttle return spring looks good. I’ll take a look at the turbo outlet today to be sure. My thinking, and I definitely could be wrong, is that’s it’s gotta be on the fuel side because the fuel shutoff works as it should. Thinking that if it was running off it’s own oil then it would wanna keep running or at least sputtering when the shutoff is pulled. Right now when you pull the shutoff it’s working normally as it always has. I’ll report back after I check the turbo outlet. thanks

 

[ToddJK]

If the throttle return spring and cable is dirty, it can stick intermittently. I've had that happen to me before. Soaked it in lubricating oil and worked it back and forth and the problem disappeared. It's possible too that the return spring can be getting weak. Next time you start it and it runs wide open, play with the fuel pedal or wiggle the return spring and cable and see if that works, if not, then you know it's in the pump, that is if the turbo isn't leaking oil or anything.

 

[Floridianson]

As said above check all linkages / pedal and what not's for binding ect. Also the throttel shaft linkage arm is sitting on the idle set screw and not hung up when engine not running. You can also start the engine with the timing shut down rod cover off and work the fuel control unit assembly with your finger. You said it was working free so have someone else hit the starter or use remote starter switch and control the fuel delivery with you finger and see if you can bring it down to idle. Easy to shut down with finger if control is free and correct just by pushing the linkage back to the firewall or 4 oclock position.

 

[will-m]

So fingers crossed I think I’ve got it squared away. After scouring the depths of the internet I came across this video.

I changed the o ring when I cleaned the fuel rod and ran the screws on the bridge back in tight. I didn’t realize that the fuel rod floats when the truck is running and that the little bit of drag from the new o ring would be enough to cause issues. I was thinking of it as more of an on/off switch. Loosened up the bridge screws and ran them back in finger tight plus a quarter turn and it fired right up and idled well. Just need to safety wire the bridge screws and should be good to go. Thanks to everyone for the replies.

 

[rustystud]

So fingers crossed I think I’ve got it squared away. After scouring the depths of the internet I came across this video.

I changed the o ring when I cleaned the fuel rod and ran the screws on the bridge back in tight. I didn’t realize that the fuel rod floats when the truck is running and that the little bit of drag from the new o ring would be enough to cause issues. I was thinking of it as more of an on/off switch. Loosened up the bridge screws and ran them back in finger tight plus a quarter turn and it fired right up and idled well. Just need to safety wire the bridge screws and should be good to go. Thanks to everyone for the replies.

It's information like this that should be mentioned when asking for help. We didn't know you had messed with the fuel rod assembly. You just said it would not run right after sitting for a few weeks after doing some brake work and heater delete.
In the future, you need to mention "all" the work you did leading up to the problem.
That way we can have a better idea of what is really going on.

 

[will-m]

It's information like this that should be mentioned when asking for help. We didn't know you had messed with the fuel rod assembly. You just said it would not run right after sitting for a few weeks after doing some brake work and heater delete.
In the future, you need to mention "all" the work you did leading up to the problem.
That way we can have a better idea of what is really going on.

The initial WOT issue was after nothing but brake work and a flame heater delete. I didn’t change the o ring until I started troubleshooting and pulled the fuel rod. Only changed it because I was in there already and it was in bad shape. Still had WOT after everything went back together. At that point I loosened up the screws on the fuel rod and it ran. Thought I had it but went to mess with it today and now it’s bouncing between 1000 rpm’s and just shy of stalling. Had to walk away from it for a little bit cause I was frustrated but will be back messing with it tonight.

 

[Floridianson]

Reassembled fuel rod, sitting around 7 o’clock with truck off, moves smoothly toward the firewall and snaps back freely.

This post is what had me barking up the wrong tree. Fuel rod = Fuel control unit assembly. You said in first post the fuel control unit assembly was working correct. In almost all cases it is the fuel control unit assembly stuck in full fuel position on start up and stuck so well governor and sometimes even the shut down cable will not work. It has been said to leave the shut down cable pulled out when you walk away from the truck. That way if fuel control is stuck at least it will not start and we just have to fix the sticky control. Also it has been said if you were to leave the shut down cable pushed in or run position and truck was left in gear if the truck rolled or got bumped it could start and be a big problem. Glad you got it figured.