M923 High idle

[ClintA]

The Ranch bought a M923 that had been sitting for who knows how long. Long story short the PT pump was gummed up (remind you of pine tar) the throttle shaft was so sticky that the spring on the throttle linkage was not strong enough to pull it back to Idle, so reaching down or pulling up with toe it would die. So taking the PT pump apart and cleaning everything the throttle shaft is free to move back and forth with no effort. Starting the truck and now she wants to run off, so I did research and tried to adjust the throttle screw and still no dice. The truck wants to idle close to 20,000 RPM's no matter what I do. I took the throttle linkage off and made it as short as I could and that lowered it down to 19,000 RPM's. What am I missing?
Thanks in advance, Clint

 

[wrenchturner6238]

It sounds like to me that something did not go together right; hooking into the fly weights.

 

[WillWagner]

You are missing the fact that you do not have a pump stand. Did you take the throttle shaft out? If so, you most likely didn't get the governor weights and assist plunger installed correctly. You tried to adjust a throttle screw. There are ZERO adjustments you can do. You should take the pump off and take it to a place that does them for a living. Not trying to be a deek, but seen it a bunch of times. I think the last guy ended up breaking the pump housing.

 

[ClintA]

There was one thing that I am not sure went back right, inside the governor weights there was a needle with some shims and a small spring, they fell out when getting out of the bucket, the shims stayed on so we knew what side of the needle the shims stayed on. This is how we put it back together, with the weights pointing up towards the sky, I put the spring in then the shims on top of spring and the smallest part of the needle pointing up then folded the weights back to upright. Is that right or did I get that wrong?

We have a PT pump off another engine that I will put on the 923, I just would like to know what we did wrong. We don't have a pump stand, we live out in the middle of God's country (1000 miles from anywhere) and was just trying to save sending it off to get fixed. Thanks for all your advise!!!!

 

[74M35A2]

The Ranch bought a M923 that had been sitting for who knows how long. Long story short the PT pump was gummed up (remind you of pine tar) the throttle shaft was so sticky that the spring on the throttle linkage was not strong enough to pull it back to Idle, so reaching down or pulling up with toe it would die. So taking the PT pump apart and cleaning everything the throttle shaft is free to move back and forth with no effort. Starting the truck and now she wants to run off, so I did research and tried to adjust the throttle screw and still no dice. The truck wants to idle close to 20,000 RPM's no matter what I do. I took the throttle linkage off and made it as short as I could and that lowered it down to 19,000 RPM's. What am I missing?Thanks in advance, Clint

19,000RPM and 20,000RPM, did you replace it with a turbine engine? Just kidding. From one Clint to another, had to have something to say..... People part out the NHC-250's here all the time for free or nearly. Just grab a pump from them, bolt it on, and be done with it.