MEP 701A Governor Apparently Not Working At All

[cuad4u]

I recently acquired a trailer with two MEP 701A generators and a generator A / generator B selector switch mounted on the trailer. All I really wanted was the trailer to mount my MEP 003A on. Lacking a current project I decided to see if I could get the MEP 701A's going. After a bit of work which I won't go into here, one is working perfectly and will load test up to 4500 watts.

The other one is running and producing voltage but the engine loses RPM as soon as I apply any significant load, even 1000 watts. If I apply the rated 3000 watts, the engine will slow down and die within 10 seconds. If I manually push the throttle with my finger the second generator will operate into a 4500 watt load without any noticeable stress on the engine.

The throttle and governor linkages appear to be in good condition and "match" those on the working generator. I am quite sure the problem is inside the governor housing, because when any load is applied the governor does not move the throttle lever to increase engine power as it does on the working generator.

I have searched and read every TM I can find on-line. I found several references to governor removal, droop adjustment, and re-installation, but nothing about the "innards" of the governor and what to expect when I take if off the engine and open it up. I guess the governor was just replaced as a unit and was not repaired by the military.

I expect to find something inside the governor broken or "stuck". Before I remove it from the engine and open it up I wonder if anybody has removed, opened up, repaired, and re-installed a governor on a MEP 701A? If so I am interested in how it works and what to expect and any pitfalls I may get into when I remove it from the engine and open it up.

Thanks...................

 

[Isaac-1]

While I don't know any details about this particular governor, most of these type units use a flyball weight system to operate the governor and my first guess would be sticking flyballs or linkage. How long have you let it run, it is possible that given a little time the sticking problem could free up?

 

[leedawg]

I recently acquired a trailer with two MEP 701A generators and a generator A / generator B selector switch mounted on the trailer. All I really wanted was the trailer to mount my MEP 003A on. Lacking a current project I decided to see if I could get the MEP 701A's going. After a bit of work which I won't go into here, one is working perfectly and will load test up to 4500 watts.

The other one is running and producing voltage but the engine loses RPM as soon as I apply any significant load, even 1000 watts. If I apply the rated 3000 watts, the engine will slow down and die within 10 seconds. If I manually push the throttle with my finger the second generator will operate into a 4500 watt load without any noticeable stress on the engine.

The throttle and governor linkages appear to be in good condition and "match" those on the working generator. I am quite sure the problem is inside the governor housing, because when any load is applied the governor does not move the throttle lever to increase engine power as it does on the working generator.

I have searched and read every TM I can find on-line. I found several references to governor removal, droop adjustment, and re-installation, but nothing about the "innards" of the governor and what to expect when I take if off the engine and open it up. I guess the governor was just replaced as a unit and was not repaired by the military.

I expect to find something inside the governor broken or "stuck". Before I remove it from the engine and open it up I wonder if anybody has removed, opened up, repaired, and re-installed a governor on a MEP 701A? If so I am interested in how it works and what to expect and any pitfalls I may get into when I remove it from the engine and open it up.

Thanks...................

I have not removed the governor however I have a 701a awaiting restoration along with my 803a if I ever get around to it. Im still trying to get the fuel cutoff solenoid on the 701a to work so I can at least get it to start. So I eagerly await your photo documentation of the removal and rebuild of the governor on this unit Hopefully somebody else here knows a bit more bout it but seems as though it is not a heavily talked about unit.

Good luck

lee

 

[cuad4u]

I have not removed the governor however I have a 701a awaiting restoration along with my 803a if I ever get around to it. Im still trying to get the fuel cutoff solenoid on the 701a to work so I can at least get it to start. So I eagerly await your photo documentation of the removal and rebuild of the governor on this unit Hopefully somebody else here knows a bit more bout it but seems as though it is not a heavily talked about unit.

Good luck

lee

I have "restored" numerous 002A and 003A generators and I know them quite well. The two 701A's I have are the first that I have ever seen and obviously I know NOTHING about them. If the fuel cutoff solenoid in a 701A does not retract, make sure you have at least a couple of gallons of fuel in the tank. There is a float switch in the tank on the 701A's that won't let the fuel cutoff solenoid retract unless there is a gallon or two of fuel in the tank. "Ask me how I found this out"?!?!

 

[cuad4u]

While I don't know any details about this particular governor, most of these type units use a flyball weight system to operate the governor and my first guess would be sticking flyballs or linkage. How long have you let it run, it is possible that given a little time the sticking problem could free up?

Thanks Isaac. I also "assume" the governor is the "fly ball" type. My guess is that one or more fly balls are stuck or maybe a spring is broken. Best I can find out, these two generators sat idle for many years before they were offered for sale. The good part is I have two of them. One works 100% so at least I have a working unit to compare to the unit with the governor problem. I think the problem is inside the governor because the engine runs perfectly under no load. When I set the engine speed so I get 62 Hz under no load and then apply just a little load, the engine starts to slow down. As the load is increased the "arm" attached to the governor does not move to increase the throttle like it does on the working unit. I plan to check and re-check everything before removing the governor and opening it up. Whatever I find will be posted here.

 

[cuad4u]

SUCCESS!! Will post details in the morning.

 

[cuad4u]

In my original post I was asking for information why the governor "arm" would not move on a MEP 701A and for anyone who had experience working on MEP 701A generators.

First a little background. Recently I acquired two MEP 701A generators mounted on a trailer. All I wanted was the trailer to mount my MEP 003A on, but in order to get the trailer I had to buy the two 701A generators that were mounted on the trailer. Up until that time I had never even seen a MEP 701A generator, much less have any idea how they worked. After removing the two generators and mounting my 003A on the trailer, and lacking a current project, I decided to see if I could get the 701A generators running.

I got the first generator working 100% within an hour. All it needed was oil and the fuel system primed. Even though it is rated at 3000 watts, it will load test 4500 watts with an indicated 110% current draw.

The second generator started right up and settled down at 62 Hz and the voltage was a stable 120/240 under NO LOAD. However when I applied any load, even 1000 watts, the engine started losing RPM and eventually stopped. The larger the load applied, the faster the RPM dropped and the faster the engine died. Upon examination of the throttle and governor linkage, it was obvious that the "arm" coming out of the governor that is supposed to move the throttle to increase engine power under load was not moving. As I originally posted, I assumed there was a problem inside the governor - maybe a stuck fly ball etc. I was prepared to remove the governor assembly and tear it apart to hopefully find and correct the problem.

Yesterday afternoon I spent a while just looking at how the governor and IP linkages work. It was a big help to have a working 701A to compare the non-working 701A to. It was then that I discovered that on the non-working 701A the throttle cable was broken somewhere inside the sheath. I understand this is a common problem with 701A's. I also understand that throttle cables for 701A generators are not available at the present time. Calls to Delks and Green Mountain Generators confirmed this.

Apparently at some time in the life of this generator "somebody" tried to compensate for the broken throttle cable by turning some or all of the throttle and governor adjustment bolts (stop bolts) in the linkage. There are 3 or 4 adjustment bolts that control or limit movement of the throttle linkage and set things like engine idle RPM, maximum engine speed, etc.. Apparently this worked as long as there was NO LOAD on the generator - engine RPM was 3600 and Hz was 60 under NO LOAD. But as soon as a load was applied, the governor "tried" to compensate by moving the the throttle linkage to increase engine power. But since the adjustment bolts in the linkage were turned too far, they "bottomed out" which prevented the throttle linkage from moving when the governor tried to move the linkage to increase engine power under load. Consequently the engine lost RPM and eventually died when a load was applied.

I had a used throttle cable that came off a 002A parts generator. I cut it to 24 inches and installed it on the 701A. It is not a perfect fit, but it works until I can find the proper throttle cable. Then using the working 701A linkage adjustment bolt positions as a "pattern", I backed off all the linkage adjustment bolts in the non-working 701A so they matched the clearances on the working 701A.

Voila! The second 701A cranked right up. I adjusted NO LOAD engine RPM until the Hz gauge indicated 62 Hz. As soon as I applied a load, the governor "arm" was able to move the throttle linkage to increase engine power as a load was applied. It took about an hour to "fine tune" all the adjustment bolts and the linkage. Finally I had to adjust (shorten) the plastic link that connects the governor linkage to the IP.

After all this the second generator operates just like the first one. Both will load test to 4500 watts without any fuss. The % current gauge on both generators indicates 110% under a 4500 watt load. Both generators are set at 62 Hz under no load. Hz drops to 59.5 as indicated on a Fluke 87 meter under a 4500 watt load.

I guess the moral of this story is none of us knows the history of items purchased at a GL sale. Also do not automatically assume there a major mechanical or electrical problem when a generator does not work as it is supposed to. Often the problem is simple, IF YOU KNOW WHAT TO LOOK FOR. In the case of MEP 701A generators I will be the first to admit that I did not know what to look for. In fact I did not know anything about them.

All is well that ends well!

 

[Isaac-1]

This reminds me of spending much of 3 weekends tracking down a voltage control problem on my MEP-003a just to find someone had installed the T-2 transformer upside down / backwards.

 

[leedawg]

Thats good news great to hear it worked out well for you very helpful to have a runner to compare the none runner to. I do not have that luxury unfortunately. Would be great if you posted a bunch of picks of the governor linkage adjusted to where it should be and also your throttle cable mod. About the throttle cable why does the 002 one cut back not work well seems like they are the same thing just different lengths hopefully mine is not broken will have to go out and look at that this weekend. Great post though good to have more info on these units.

Lee