JM254 Injector Pump? Pic

[Bob Rooks]

If you put too much oil in, the governor flyweights will become submerged and cause premature governor failure.
I have never heard of a runaway from this condition, only that the engine cannot be controlled beyond a certain speed or will not start.

 

[hill]

If you put too much oil in, the governor flyweights will become submerged and cause premature governor failure.
I have never heard of a runaway from this condition, only that the engine cannot be controlled beyond a certain speed or will not start.

I saw a photo showing six steel balls. There was no reference to be able to assess their size or position within the pump but could something like that be the governor weights you're refering to, Bob?

That picture was in the site that stated the four ounce capacity for lube oil in the pump, and it all begins to make sense in light of your submerged weight warning.

To play it safe I think I'll go back and let out about half the oil I put in there.

 

[Bob Rooks]

I'm not sure what those six steel balls were unless they were part of the actuator bearing. Most of the flyweights I've seen lately are L-shaped pieces of various sizes (depending on the governor), some are stamped and formed steel, others are cast steel, and some of the small units look like sheet metal.

Steel balls haven't been used for flyweights for many years. In olden times, sometimes when the governor's and engines speed was exceeded, it caused the pins in the balls to break away from their mounts and fly against the wall of the housing; hence the saying; "balls to the wall". Usually the engine came to an idle or stopped under load because of the counterbalance spring overcoming the centrifugal force of the missing flyweights.

Interesting note: Mechanical governors are slowly dissapearing. Woodward's 2301 electronic governor has been around for years, and is about the size of a pack of cigarettes, has an actuator on the engine, and a mag pickup on the flywheel. Other manufacturers have been following suit.

 

[RonMar]

Those steel balls are the flyweights. Here is a link to a thread about erattic idle a few weeks ago. In post 6 I described governor operation.

http://www.tractorbynet.com/forums/chinese-tractors/105747-idle-surge-high-idle-eratic.html

 

[Bob Rooks]

Dang! That's a new one on me. I understand how it works though; steel balls move against the cone. I wouldn't consider them to be flyweights though because they aren't attached to the actuator. They are captured free-floating.

 

[hill]

Good link, Ron.

The service letters contain the definitive answer to the question of how much is too much oil in the injection pump by pointing out a screw to remove while filling. When oil comes from the screw the pump is full. There's a photo showing the banjo drain equipped bolt (marked "B" in the photo) forward of the priming pump and directly below the #1 injector pipe.

For the record, with ten ounces in the pump no oil came out of the above screw when I removed it. A little odd since the text in that bulletin states that the capacity of the reservoir is four ounces. I'll fill it tomorrow - it's dinnertime now.

Interesting governor mechanism. The balls made me think of the Roman lap counter at the chariot race in 'Ben Hur' for some weird reason.

 

[RonMar]

Since their relationship never changes with the cones that they are forcing apart, as RPM increases, the force the ball bearings apply is linear over the entire RPM range. Captive flyweights pivot from a fixed point so their oputput force is only linear over a very narrow range when their pivot arm is perpendicular to the line of force. The applied force decreases the farther the pivot arm moves from perpendicular. Captive weights are more suited for running at a fixed RPM like on a generator.

 

[Bob Rooks]

Neither the balls & cones or the flyweights would allow the rack to return to the idle position and stay there were it not for the variable-rate compensator springs (sometimes double springs), which provide the linearity. In some of the larger governors this is accomplished by hydraulics, in that the governor/actuator has it's own oil pump and hydraulic compensating system.
Remember, there is no direct mechanical connection between the rack and the throttle control.
Now I'm going to have to dig out my governor books again.

 

[Red55]

Hi Hill- I followed Chip's advice which is also the advice of some of the service information I've read; which is to fill until it comes out of the overflow hole and wait until it stops dripping. Just glad that I changed everything (oils) before start up. (it was definitely low maybe factory just adds oil and does not wait or open overflow? ?) Also thinking that our pump is the chinese latest version & they decided to increase the oil sump size- because it doesn't look like the other pumps that I have seen. Maybe the vendor change capacity and the factory doesnot know yet? Ed

 

[hill]

Hi Hill- I followed Chip's advice which is also the advice of some of the service information I've read; which is to fill until it comes out of the overflow hole and wait until it stops dripping. Just glad that I changed everything (oils) before start up. (it was definitely low maybe factory just adds oil and does not wait or open overflow? ?) Also thinking that our pump is the chinese latest version & they decided to increase the oil sump size- because it doesn't look like the other pumps that I have seen. Maybe the vendor change capacity and the factory doesnot know yet? Ed

Yeah, and there's more: after filling the pump to the point that oil comes from the overflow banjo and is allowed to drain down, run the tractor. I found mine dripping even more out the little valve after a good warmup.

So that we know we're talking about the same thing here's my overflow, installed and not:

http://i130.photobucket.com/albums/p263/twagger/JinmaFPoverflow.jpg

http://i130.photobucket.com/albums/p263/twagger/JinmaFPoverflow1.jpg