CK2620 only going to 1800 RPM

FlightGuy · Thursday at 1:52 PM

Hi, new to tractors and not a mechanical guru by any means. My 2022 CK2620 at full throttle only goes to about 1800 RPM. I’ve only got just over 50 hours on it. Seems like everything works well but I’m guessing these tractors should be able to get up beyond 3k rpm? The throttle cable was a bit loose ( a lot of play before the throttle started moving) and that was easy to fix but didn’t solve the issue. Looks like there are set screws that have wire through them at the plate the cable moves (governor plate?). One appears to be for idle and the other for full throttle. Does that set screw need to be adjusted? I’ve already changed the fuel filter with no change in idle speed. I’m not a heavy user and mostly have just used it to pull logs, front loader work and decent amount of backhoe work.
Appreciate any insight/guidance.

ptsg · Thursday at 2:02 PM

That tractor is rated at 2400 RPM, so at the very minimum, it should rev at least to that. The max throttle should be more or less around 2800RPM for torque rise purposes.

Can you tell if that's the engine that isn't revving up that high or could be a tachometer issue not reading correctly? I would imagine having only 1800 RPM, you would notice it being fairly under powered.

FlightGuy · Thursday at 2:08 PM

Hmm…hadn’t really thought about a tach issue. The tractor seems to run fine. Backhoe and loader work without any noticeable issues. When I’ve pushed snow with the front loader i actually prefer to run the engine at a reading that is more like 1k rpm and it still works great. Nearest tractor service center to me is over 3 hours away. Any idea if these tachs are known to have problems?

FlightGuy · Thursday at 2:12 PM

If I adjust those set screws (the high one) on the throttle plate (?) that is actuated by the throttle cable will I be able to see an increase in rpm or are those set screws more for fuel delivery vs rpm? The screws have wire through them so I’m guessing they aren’t meant to be adjusted regularly

ptsg · Thursday at 2:27 PM

I wouldn't mess with any set screws until we figure out exactly what's going on.

Just checked the service manual. 1150 RPM is the idle speed for these engines. 2600 RPM is the max RPM with the throttle lever hitting the stops. These engines are detuned in both fuel delivery and RPM to meet the emissions requirements without needed a DPF.

If you're saying you're setting the throttle at around 1000 RPM, I'll say it's definitely a tacho issue.

FlightGuy · Thursday at 2:34 PM

Interesting. Must definitely be a tach issue. Idle speed definitely isn’t anywhere near 1150. It reads more like 150-200. Ha! And the tractor starts and idles wonderfully.

Now, to satisfy my knowledge debt what are those set screws with the piece of wire through them at the throttle or governor plate called and what are they for?
Thanks!

ptsg · Thursday at 2:43 PM

On the throttle lever, one should set the minimum RPM and the other sets the maximum RPM. There is probably another one that adjusts the stop lever. The piece of wire is a seal so they know if it's been tampered.

For the tachometer, there is a pick up sensor on the side of the injection pump. Since that's easily accessible, it might be worth taking a look at the wires and plug to see if those are in good condition.

Another possible issue, could be the plug behind the dashboard.

FlightGuy · Thursday at 3:35 PM

Thank you! I’ll have a look at the pick up sensor and then the plug behind dashboard.

And thanks for explaining the set bolts to me.

FlightGuy · Thursday at 3:57 PM

Wires all look good on the sensor. Is the sensor itself something I can remove/clean easily? Or is it not as easy as battery disconnect, pull bolt on sensor and slide it out?
I had a crankshaft position sensor on a car that needed to be removed and cleaned on rare occasion to keep it happy.

Midniteoyl · Thursday at 5:49 PM

FlightGuy said:
Interesting. Must definitely be a tach issue. Idle speed definitely isn’t anywhere near 1150. It reads more like 150-200. Ha! And the tractor starts and idles wonderfully.

Now, to satisfy my knowledge debt what are those set screws with the piece of wire through them at the throttle or governor plate called and what are they for?
Thanks!

My CK3510 idles around 900-1000 rpm. I push it up to 1400 then use Linked Peddle for loader work/snowplowing.

If you are showing an idle around 200, then something is off with the tach and or tach signal.