Our model CS56 pro will idle all day but it will not rev up

You most likely have a transmission that has seen it's better days, very common issue in these models.

Here's a link on your chain Brad. Chain Size of the John Deere CS56

Have it looked at by a dealer,iam not sure here but i think you have a vacumn leak like the feed pipe to the servo split but really you need a mechanic who works on these cars day in day out and they will go straight too the problem for you

That CS-56 soil compactor is set up with a govenor to stay at a fixed speed! If you need to change the speed you need to reset the govenor bu adjusting it to tighten the spring. If the revs increase in that direction OK, otherwise turn the adjustment the other way!

Sounds like a carb issue, the L screw on the carb adjust the fuel mixture from idle to half throttle, i would richen the L screw by unscrewing 1/4 turn, this should improve the running, however there is a special tool to adjust the screws, part no. 530035560, the screws are fuel, not air screws, increase a shade more if it is still not idling or accelerating properly.

The mixture screw has its main effect at idle.It is called the idle mixture screw. So may not help fuel consumption a lot.

To adjust it.
turn it in until it stops and count the number of turns exactly(so you can put it back if adjusting doesnt work)
Then screw it back out to the original position, and start the bike.
If you screw it out about half a turn, from the original position, the revs should rise and then become uneven, with the revs rising and falling(this is lean)
If you screw it in half a turn from the original setting, the revs should slow down and maybe stall the engine(rich)
Pick a place in between the two, where the idle is smoothest.

Of course make sure the bike is serviced first, clean or new air filter, new plug, new oil, adjust valve clearances(if it has valves) check tyre pressures, adjust chain (or replace if old)
The new air filter may make the biggest difference, as it gets dirty or old,it will richen the mixture right through the rev range.
And fix the shift key on your keyboard please.

it will idle high with air con on and revs will go up and down try turning air con off it that fixes it then there is no problem

MODEL N 98067 / MINICAN PRO Rev 2 / general electric

Hi there,
This sounds like your idle control module has gone bad. Since the machine will rev up to weld speed if you turn the switch to high it can't be that the solenoid has gone bad. Some models of engine driven welders from Miller use a little module, others have the idle circuit built into the control board, can't tell which yours is without a model number. This problem could also indicate a broken current transformer since letting the unit heat up makes things better. I'd use an ohm meter to check the resistance of the CT while it was cold to see if it goes from open circuit to just a few Kohms of resistance when it gets "room temp".

Rank me if this helps,
Carl