Combines rotor won t start

Both the PTO clutch and hydraulic drive rotary screen are driven by the same engine accessory drive mounted hydraulic pump. One of the problems with tyis system is the distance that the pump sets from the hydraulic reservoir. This is why the late 21's that had this system were converted to allow the air screen to run all the time rather than when the separator was engaged. Couple of things to check would be clutch application pressure. There is apressure port on the pto near the accumulator if memory serves. Might check this. Might also want to check accumulator pressure with the appropriate guage_charging setup. (have the dealer do this). With the header on the ground is the hydraulic oil filling at least the lower sight glass and preferrably also just filling the top one. Might also change filter. The motor on the rotary screen air locking when changing oil and filter has been a problem. Also led to premature PTO clutch failures in my opinion due to low pressure caused by air. The A-post controlls the PTO engagement so engine speed must be above 1000 rpm and below 1800 rpm. Hope this helps. e-mails is besthornb@bartonccc.edu.

I have the right diagnostic gauges to check the pressures, but don't have a book to give me the range. Do you know itIJ

With the oil hot, separator on and engine at high idle the rotary screen should be running above 195 rpm. If below 195 rpm check the following: separator filter restriction indicator with the same previous conditions; inspect plumbing for routing, kinks, loose clamps, etc and correct as needed; inspect the rotary air screen relief valve located under the air chute; last resort, replace pump. PTO specs are as follows 1100 rpm separator off 190 psi minimum 2450 rpm separator off 210-235 psi 1100 rpm separator on 180 psi minimum 2450 rpm spearator on 200 psi minimum There is always some oil flow in the clutch circuit due to an orifice in the supply tube. This ensures that oil will continue to flow thru the pto cooler to cool the pto oil. PTO oil and filter change interval is 300 hrs. If you rebuild or install a rebuilt pto change after the first 10 hrs again at 50 and then normal interval.Field experience shows this works. Separator accumulator is 65 psi dry nitrogen.

thanks for the specs, now if I can find the time to check them out, everything has been working fine since the day it wouldn't start.

My guess is that the system air locked for some reason. Normally happens when you change oil and filter in the PTO or it sets for a period of time. May not happen again. My e-mail is in a previous post above. let me know if you have any further trouble.