MEP701A problem

[epitts]

I am working on a 701 for a friend it runs good and makes power. The problem is the idle will continue to creep up. I set the hz to 60 on startup it will slowly increase up to 69 hz. I replaced the throttle cable but it did not help, made sure all linkage was lose. Seems the throttle has no effect on speed after warm up. Help

 

[epitts]

bump, No one has any ideas!

 

[1800 Diesel]

Even on my larger generators (MEP2, 3 & 4 models) I have noticed a slight RPM increase & freq rise after about 10 minutes of running with no load. However, when the units are under a good load, the speed tends to stabilize. Frequency doesn't change as much as yours though--more like 2-3 hz, not 9. You may have an injection pump problem, something internal or have you adjusted the governor any? Is there a droop adjustment on that unit?

Kevin

 

[Ray70]

What happens if you readjust the throtle after warm up? Does it creep back up to 69Hz or does it stay stable once the machine has warmed up?

 

[Isaac-1]

My MEP-701a also has a 1-2 HZ increase after it warms up

 

[glassk]

TM 5-6115-615-12



Not sure if this may be of use


Recheck no load high idle speed. The no load high idle speed should fall
between 3850 and 3900 RPM (or equivalent frequency).






4-45. GOVERNOR DROOP ADJUSTMENT.




(See Figure 4-36).













To properly set the governor droop requires the use of

a three kilowatt (3 kw) load bank; however, approximate

field adjustments can be made when necessary. For

proper droop specification, the change in rated speed

or frequency between no load and full load (3 kw)

should be 1.5-3.0 percent.

Operate generator set at rated speed and load until it reaches operating

temperature.

Adjust set to rated speed at full load using manual speed control.

Remove load and record new stabilized speed (Hz).

Calculate droop. Use the following formula to calculate droop:

Droop= no load speed (Hz)-full load speed (Hz)

full load speed (Hz)

(5) Adjust droop screw (1) and recheck droop.

X 100 percent


NOTE



By adjusting droop screw, droop can be changed by

moving governor spring closer to (less droop) or away

from (more droop) the governor cross shaft.


4-

 

[epitts]

What happens if you readjust the throtle after warm up? Does it creep back up to 69Hz or does it stay stable once the machine has warmed up?

It acts like the throttle cable is not there, throttle will increase idle but will not decrease idle.

Started it today did not move throttle started at 55hz and as it warmed up ran up to 69 hz at which time I turned it off.

 

[ETN550]

It acts like the throttle cable is not there, throttle will increase idle but will not decrease idle.

Started it today did not move throttle started at 55hz and as it warmed up ran up to 69 hz at which time I turned it off.

Find this manual

MARINE CORPS TECHNICAL MANUALARMY TECHNICAL MANUALTM​

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05926B/06509B-34/3​

TM 5-6115-615-34NAVY PUBLICATION NAVFAC P-8-646-34​

AIR FORCE TECHNICAL ORDER TO 35C2-3-386-32

And go to section 7-6 and start with #4 and follow all the steps in order until #12 is complete on page 7-8. If you do not have a 3kw load then go to about 85% on the load meter. Put the droop screw in the middle of the threaded block to start with.

I find a LOT of units have these problems because people play with the settings and the governor gets out of whack. When it is set up correctly the unit will start fast, run crisp, accept full load with little drop and hold frequency. There is no short cut procedure. It might take an hour the first time but it can be done in 25 - 30 minutes easy the next time. Everyone who owns one of these sets should do this procedure.

 

[epitts]

Thanks for the help everybody, I knew you would know.