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 | John N
Join Date: Posts: 1 
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2004-01-05 73088
755 with 341 hours. It bogs down going up even a slight hill using the mower to the point of stalling without a hint of smoke. Downhill runs fine. I thought it might not be getting full fuel flow. Changed fuel filter. Supply pump OK. Good flow to the injection pump. Injection pump and injectors tested at diesel shop. All excellent. Governor appears fine. Spins up to proper speed, no surging. I have both engine and chassis manuals, everything appears to be at spec. One question is the fuel controller on the back of the governor. There is nothing in either manual that says how to adjust it. Anyone know? Could it be a hydraulic flow problem? Seems like low hours for that. Any input to this puzzler is welcome.
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 | Chief
Join Date: Jul 2003 Posts: 4297 Southwest MiddleTennessee 
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2004-01-05 73128
Have you checked the fuel pickup inside the fuel tank for contamination restriction? ....
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| Chief
Join Date: Jul 2003 Posts: 4297 Southwest MiddleTennessee
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2004-01-05 73129
Where did you get the fuel you are burning in it now and how old is it? ....
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| Johnln
Join Date: Jan 2004 Posts: 4 TN
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2004-01-05 73136
Fuel is auto diesel with a little additive for lubrication. Tank is clean. Flow to the inlet of the injection pump is good. ....
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 | yooperpete
Join Date: Jan 2004 Posts: 1413 Northern Michigan 
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2004-01-05 73141
Were you at one time able to do what you are now attempting? Are you in low range running 540 PTO rpm? ....
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 | Art White
Join Date: Jan 2000 Posts: 6898 Waterville New York
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2004-01-05 73149
How's the hydro working? anything different there? It does worry me as to the fact youaren't getting any smoke out the exhaust as they normally will a little when working hard. You did eliminate that as a sourse of problem by having it checked out. ....
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| Chief
Join Date: Jul 2003 Posts: 4297 Southwest MiddleTennessee
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2004-01-05 73151
Does the engine pick up the load if you put the hydraulics into bypass? (i.e. can you here it lug down and smoke more due to the load?) It almost sounds as if the govenor is not properly compensating for engine load. If the engine stalls out under a heavy load you would get tons of smoke if it was. If it was a hydro problem, sounds like the suction filter & screen is restricted but that would not necessarily kill the engine in the manor you are saying. ....
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| Johnln
Join Date: Jan 2004 Posts: 4 TN
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2004-01-06 73204
This one is strange isn't it? Yes, it used to run up hill, down hill, sideways with no problem. I have not checked anything in the hydraulics as yet. It runs strong downhill and flat, but even the slightest incline bogs it down. But you would still think it would smoke under heavy load unless it was at the power limit of the machine. That's why I'm still leaning toward fuel control. I think the governor is calling for fuel, but a control limiter or something is throttling it. There is that fuel controller on the back of the governor that is mysterious to me. I cannot figure out what it does. Nothing in the manual says what to do about it other than point it out on a diagram. Also, the mower deck does turn freely and easily by hand at the shaft - no binding. ....
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| Chief
Join Date: Jul 2003 Posts: 4297 Southwest MiddleTennessee
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2004-01-06 73212
I think the problem may between the pump or governor. Have you run these symptoms by you local John Deere dealer Service Tech? I would do that before I removed anything but I believe both would have to go to a diesel pump shop for repair if there is a problem. The fact that the engine bogs down upon encounter a load without showing signs of fuel enrichment is an indicator of a problem with the pump and or govenor. ....
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| wallac
Join Date: Dec 2003 Posts: 70 Pennsylvannia
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2004-01-06 73213
yOU HAVE SAID THAT IT DOES IT WHEN YOU ARE RUNNING THE MOWER, HOW DOES IT RUN IF YOU ARE NOT RUNNING THE MOWER? ....
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| TomG
Join Date: Feb 2002 Posts: 5406 Upper Ottawa Valley
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2004-01-06 73216
The mystery unit may be an anti-smoke device. Some of them do mount onto governor housings. Their purpose is to limit smoke due to excessive fuel delivery when governors switch to the full-load position. I guess a faulty one could cause the problem, but they're pretty. Most manuals say little about adjustments because ordinary techs aren't supposed to do them. Testing governors to determine if they actually are moving against their full-load stops also is tricky.
I'm guessing that you inspected the linkage and saw how the control arm moves when the hand throttle is moved to full. If you haven't already do so you might disconnect the linkage and move the control arm to see if it moves freely through its full range. A stuck rack could be the problem.
You might try lifting heavy loads with a loader or 3ph to see if the hydraulics have normal power. Most engines have a distinctive sound when they go to max-load. Many governors switch between fast idle and max-load when they're worked and a heavy bucket should cause it to switch. If you can recall the sound and hear it when the hydraulics are worked then maybe the HST has a problem such as a bad relief valve.
There are things other than the governor in trouble shooting tables for low. Most other problems cause some smoking so I'd be thinking about the governor as well. It'd be good to check other possible problems out before taking the pump to a shop. ....
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| Johnln
Join Date: Jan 2004 Posts: 4 TN
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2004-01-06 73261
I'll have to ride around without the mower to check any bogging with just the hydro. However, the engine is pretty much loafing at that point so the governor doesn't call for much fuel.
The local JD tech is not much help. The diesel injection shop (three shops actually) was much more helpful. They seem to know their Yanmar stuff pretty well. The one thing we know for sure is there is no smoke at all when bogging down. That points to fuel starvation. The $64 question is why. Injectors excellent. Injection pump excellent (removed and tested). Supply pump excellent. Fuel filter new. Fuel tank clean. Excellent fuel flow to the inlet of the injection pump. Either the governor is failing to call for fuel (unlikely since that is just a spring for more fuel vs. weights for less fuel - and the spring seems good)or something is preventing full rack travel. But the injection pump is good and the rack is free.
I'm still intrigued by another posting that says to check hydraulic filters and screen. Will do that next. Does a dirty hydraulic filter or screen really load things up that much?
....
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 | kwschumm
Join Date: Feb 2003 Posts: 5764 NW Oregon
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2004-01-06 73265
Dumb question. Have you checked the fuel flow when you're actually on a hill? Maybe there's something about the fuel pickup that causes fuel starvation on an incline. ....
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| Art White
Join Date: Jan 2000 Posts: 6898 Waterville New York
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2004-01-06 73303
Most full service dealers have a dyno. I wouldn't waste much more time with out looking at the real results. ....
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