Hand throttle idle problem with NHC-250. RPM's rise after a minute or two.

[Carlo]

Confirmed. Every A1 I've owned does this.

 

[Floridianson]

It's a pt pump thing. They do that. Pt is "pressure timed" so as the rpm increases, even a little, the pressure increases then rpms increase and the cycle repeats. This continues until it hits the governor.

Thank you.

 

[painter paul]

I have found that setting the hand throttle just over idle when cold will keep the speed to under 1500 rpm's as it warms up.

 

[OilfieldRoughneck]

My 923 NHC-250 idles fine except when I use the hand throttle. I'll set it say at 900RPM, it will stay at 900 RPM for a minute or two and then start increasing rpm on it's own till it's screaming. Any idea what is causing this and the solution?

Both of my M923's do the same thing

 

[painter paul]

OilfieldRoughneck, please read the previous posts here for the answer

 

[OilfieldRoughneck]

OilfieldRoughneck, please read the previous posts here for the answer

I have read that, I was stating that mine also do it.

 

[162tcat]

They all do.....