Combines Bosch MW pump adjustment

Farm_Kid2

Guest
Old Pokey, Before you start turning screws, I would try bumping up the governor spring. Unfortunately, I don't know exactly how to do it, but from your symptoms, it sounds like your governor is not sensitive enough, even though it may deliver plenty of fuel. I've been told by pump technicians that for combines the MW governor spring needs to be set much more sensitive. We had one that needed 6 additional clicks on the spring, which was the "worst he had ever seen". When you get it up high enough, it may be a bit unstable when the engine starts, but smooth out in about 30 seconds. This won't change the fuel delivery, so it is safe. It just lets the governor kick in at a higher RPM so that you reach max HP at a higher RPM, which is what you need in a combine. They probably set your governor like a tractorIJ I've been told that you can click the spring up while the pump is on the engine, but I don't know the details. I'm guessing there is a cover to take off, then you'll see a lever with a series of notches. The governor spring will be hooked in one of the notches. I think you need to go closer to the pivot point of the leverIJ
 

Old_Pokey

Guest
That sounds exactly like what needs to be done. I'll start to look for this spring. I mentioned to the dealer chief that it used to be so responsive that it would "hunt" for a second or so when I snapped the throttle. Now it just sort of smoothly, slowly raises up in rpm. Thanks for the input. I'll find a diagram somewhere to locate it.
 

striker782

Guest
I highly recommend that you get someone that knows how to do this. You could cause more harm than good. It is not hard to do on the machine and some other settings need to be made at the same time.
 

Old_Pokey

Guest
That's the problem. Trying to find qualified people is near impossible. Thats why I took it to the dealer when I have a service manual. I figured I'd get someone with some knowledge to go with the price of shop fee's. Boy was I wrong. Its monday now, so hopefully the sourced shop that did the rebuild will be open.
 

striker782

Guest
The problem is that even dealer personnel are not authorized nor trained to work on the diesel pumps anymore. Our service manuals only show how to remove, install, and time the pumps. I learned elsewhere what adjustments need to be made. The newer pumps are even harder to work on and of course electronics has changed the rules even more. I would think that the shop that did the rebuild would want to get you going.
 

Farm_Kid2

Guest
I think CIH should pay more attention to how the pumps are set up. There is no reason that a person should have to remove the pump and have it checked at a pump shop for a brand new combine, yet that seems to happen. And finding the right pump shop is difficult too. I would bet that most red combines that run well have been tuned outside of factory specs. I'm not saying they need extra fuel, but a doggy governor is a disaster. Pokey, did you ever get your's looked atIJ
 

Old_Pokey

Guest
Still working on it. I finally figured out which plug to take out to get to the gov spring, but I'm afraid to turn it yet till the morons that goofed it up ok it. Its still a warranteed pump at this point. Thing is I'm 5 days into harvest now and the stupid thing just dogs. Today a neighbor that helps up combine with his 2388 came over and rode around with me for a bit. He got in the cab and the first thing he said was " whats the matter with your engineIJ". I think I'm going to twist that screw tomorrow and if they claim I voided warranty, I'll report the company to the BBB and bad mouth them as much as possible. Anyway, I really apreciate the info on the gov spring. It has to be the problem. And, I do remember that before the pump went into the shop, there was a glob of silicone in the hole where you put the wrench to uncover the adjustment. I think it was adjusted by the previous owner which is why it performed so well, and now its probably at the low of factory spec.
 

Farm_Kid2

Guest
I'm not sure there is a factory spec for it. It doesn't change the amount of fuel, unless the pump shop calibrated the fuel delivery with the rack at less that full travel. If the governor was holding the rack back, changing it now could get you into trouble. That would really make me upset with the pump shop! Here's another thought. When the spring on the rotor torque limiter gets weak, it acts just like the engine runs out of power. As you load up the machine there will be a point where the engine rpm just drops off a cliff. You have to stop the machine immediately and let the rotor clear out or it will plug by killing the engine. If you feel your in danger of plugging all the time, I would replace that spring. It's about $30. I would also consider replacing the whole torque limiter with a 2388 style (it looks the same except for the grooves milled into the face of the sheave). The newer ones really work nice on a 1680. Sorry to hear your machine is still limping along. After harvest, if you need your pump blue printed, I have just the guy. He will go through that thing with a fine tooth comb and get it right, no matter how bad the last guy hosed it up. He's a perfectionist and he takes pride in getting the governor set up right for a combine.
 

Old_Pokey

Guest
Its amazing how simular we seem to think. last year I noticed the feeling like the clutch was starting to slip. (this was when I noticed the engine starting to have problems too) I bought a flow meter and pressure guage and tested the clutch pressures and flow and they're right on the money. So I replaced the torque spring with the 400n. My old one was compressed about 1.5". The feeling of the clutch slipping is gone. I think the rack is getting full throw. Once the engine pulls down to around 2550, it will hold there pretty well. The concerns about how the pump is set is what has kept me so scared about turning any screws. But, given the performance of the engine under various loads and it has been right on with fuel usage, I'll give the dealer one more chance to get out here and make things right today. After that, I'm on my own.
 
 
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