Combines 1987 850 eng and rear beater speed

Your description of the way your governor reacts to a load is exactly how the one in my 750 reacts. I have a John Deere with a 404 diesel engine. When that 404 loses 50 rpms the pump_motor will give you all she has. IMHO that is exactly how the governor in a combine should react. Overall I'm extremely happy with my 750 after one years use, but I beleive there is much more combine capacity than the HP to make use of that capacity. let us know is you find a solution. Thanks.

The only thing that's not reading right is the rear beater speed. If you have a hand tach, check the shaft speed. It should be turning 740 at no load. If it is, check the sender,located on the left side near the middle of the rear beater pulley. The air gap should be about the width of a dime. So far as the motor speed goes, don't be afraid to take the rpm's down to 2350 or so. That Perkins is a great motor with a lot of low-end torque. At 2350 rpm's, it's still only bogged down 6%, so you've got plenty of motor left. As far as I can tell, you've got a great machine there. Sounds like you've been getting about 7 acres_hour in 60 bu. barley. Not bad! Good luck!

Ignore the engine RPM specs, 2800 rpm no load is OK, concentrate on rear beater speed. Set to 740, occasional flash to 750 rpm on digital tach. Make sure full throttle is reached on pump when lever moved in cab to full. We used to load ours till beater speed reached 720 rpm, 710 minimum. That way combine capacity doesn't suffer. If you're pulling it down to 670 rpm, either your linkage is way out or you do have a power problem. Start with fuel and air filters - worked for me last year. Beyond that, set valves, injectors and injection timing, also boost full fuel as far as you can (internal limiter ring). These machines are underpowered even with that engine. Ran an MF 860 with AV8.540 once for 2 seasons - it only dropped 20 rpm on beater speed, under almost any load. That's the way a combine should work!

I agree Skiwhiz with your comment on running with V8 vs 6. The 6 banger Perkins is topped right out when you are pushing the machine and if you get into tough ground conditions you are taking away power from the combine just to travel. A 100% loaded 6 will burn up more fuel the the V8 running at 75% load.