742B bogs down

[[email protected]]

From this forum I recently learned of the importance of oil in the governor. I topped it off, but wonder if it is damaged. When operating the engine bogs down when the drive motors are under even a modest load. This only occurs in the drive motors, not the lift cylinders. As an illustration, if I am sailing along on the level and come to a 10% grade the engine bogs down. If I relieve the pressure, the engine recovers, and I can feather it to regain rpms. I thought one of the purposes of a governor is to kick into 'passing gear' when the engine encounters a load. If I am engaged in very active work, I can compensate somewhat by operating at high rpms, but I prefer not to. Any thoughts?

 

[flyerdan]

The purpose of the governor is to maintain a specified rpm at a power setting. Think of a lawnmower; you set the throttle to max operating power and it will maintain the same (well, nearly) rpm when cutting grass or sitting still. On the small engines it's easy to see the governor search as the engine pulses, you should be able to observe the same on your 'cat engine.
Have someone watch the linkage as you put a load on the drive, even by putting the bucket down and trying to drive, that should result in the gov trying to open the throttle to compensate for the load. If the governor doesn't try to open the carb, that is the problem. If the governor does open the carb and it still bogs down, that could be an adjustment issue where it is trying to open too much, or the carb itself it out of adjustment, jet wise. The fact that you can back off (kind of like if you try to mow too much wet grass) and it will recover tends to indicate an adjustment issue.

 

[Tazza]

The purpose of the governor is to maintain a specified rpm at a power setting. Think of a lawnmower; you set the throttle to max operating power and it will maintain the same (well, nearly) rpm when cutting grass or sitting still. On the small engines it's easy to see the governor search as the engine pulses, you should be able to observe the same on your 'cat engine.
Have someone watch the linkage as you put a load on the drive, even by putting the bucket down and trying to drive, that should result in the gov trying to open the throttle to compensate for the load. If the governor doesn't try to open the carb, that is the problem. If the governor does open the carb and it still bogs down, that could be an adjustment issue where it is trying to open too much, or the carb itself it out of adjustment, jet wise. The fact that you can back off (kind of like if you try to mow too much wet grass) and it will recover tends to indicate an adjustment issue.

If it still tries to govern the motor, so the arm still moves with different loads, i think it's ok, you may just need to adjust the carb to throttle up more?
I have never adjusted one, so i don't know how it's done though.

 

[[email protected]]

If it still tries to govern the motor, so the arm still moves with different loads, i think it's ok, you may just need to adjust the carb to throttle up more?
I have never adjusted one, so i don't know how it's done though.

The service manual describes the process for adjusting the governor, so I will give it a try. I am awaiting delivery of an old time tach and dwell meter. Will report findings as they occur.

 

[reaperman]

You may want to check the ignition. Points, rotor, condenser, plugs/cables. When the Ford engine shows your symptoms, its normally one of the above causing it, the points gap is most common.

 

[[email protected]]

You may want to check the ignition. Points, rotor, condenser, plugs/cables. When the Ford engine shows your symptoms, its normally one of the above causing it, the points gap is most common.

That is also on my to-do list. Mine is the Mitsubishi engine

 

[[email protected]]

That is also on my to-do list. Mine is the Mitsubishi engine

Update--Just received a nice Sun tach and dwell meter. Brand new, but probably 30 yrs old-nice companion to my Sun timing light. Using Service manual, pg 7B-12, I checked carb adjustments, then checked the points. They were closed too much, so adjusted them. Started it up, and it runs better than it has in ages !! I did not tinker with the governor. The instructions say to hold two linkages against their stops, but don't say open stops or closed stops, then tighten screws. Instructions to tighten screws presumes that they have been loosened first ? Next instructions are to set throttle lever stop bolts. Without a deep investigation, it appears that the seat needs to be dismantled to access those nuts. Am I missing something? Why adjust those stops when there is so much available adjustment on the throttle rod where it connects to the governor ?

 

[GOM]

Update--Just received a nice Sun tach and dwell meter. Brand new, but probably 30 yrs old-nice companion to my Sun timing light. Using Service manual, pg 7B-12, I checked carb adjustments, then checked the points. They were closed too much, so adjusted them. Started it up, and it runs better than it has in ages !! I did not tinker with the governor. The instructions say to hold two linkages against their stops, but don't say open stops or closed stops, then tighten screws. Instructions to tighten screws presumes that they have been loosened first ? Next instructions are to set throttle lever stop bolts. Without a deep investigation, it appears that the seat needs to be dismantled to access those nuts. Am I missing something? Why adjust those stops when there is so much available adjustment on the throttle rod where it connects to the governor ?

Also consider that the accelerator pump enriches the fuel mixture when the governor opens the throttle quickly (as when the load on the engine suddenly increases.) The accelerator pump "squirts" a tiny stream of fuel into the carburetor throat to get the engine transitioned to the higher load condition. If it is weak or not working at all, the engine probably will run relatively well under no load, but, as you indicated, needs to be eased into a heavier load condition gradually or it will bog down or stall altogether. The accelerator pump is a small plunger pump inside the carburetor, actuated as I recall, by an external linkage on the side of the carburetor facing you as you look at the engine. You might be able to see if it is functioning by disconnecting the throttle linkage and WITH THE ENGINE NOT RUNNING looking down the carburetor throat with a mirror as you quickly move the throttle from closed to open to see if a small stream of gas appears from the side of the throttle bore. Never get your hands or eyes near the top of the carburetor when the engine is running to perform this test because a lean running engine can backfire quite a tall flame straight up when accelerated quickly. Ethanol in our modern fuel tends to degrade soft parts like the accelerator pump diaphragm or plunger on many of these older machines. Just one more idea to consider.

 

[craigb93]

Update--Just received a nice Sun tach and dwell meter. Brand new, but probably 30 yrs old-nice companion to my Sun timing light. Using Service manual, pg 7B-12, I checked carb adjustments, then checked the points. They were closed too much, so adjusted them. Started it up, and it runs better than it has in ages !! I did not tinker with the governor. The instructions say to hold two linkages against their stops, but don't say open stops or closed stops, then tighten screws. Instructions to tighten screws presumes that they have been loosened first ? Next instructions are to set throttle lever stop bolts. Without a deep investigation, it appears that the seat needs to be dismantled to access those nuts. Am I missing something? Why adjust those stops when there is so much available adjustment on the throttle rod where it connects to the governor ?

The Throttle Rod Length is specified. This centers the Governor Travel. The end screws and the spring tension may not need adjustment unless the governor has been messed with in the past. Start with the correct rod length. i only have the spec length for the Ford engines. Look in some of the Manuals for your machine. -Dick