Mep-531a Hz too low

I have a mep-531a,runs great and already maxed the throttle adjust bit still sits at 52hz in the yellow on the meter. Any idea how to verify the RPM and output is appreciated

Most modern multimeters have a frequency setting. Meter the output for frequency.

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Got that part, but how do I make it higher. The engine must be running to slow.

Follow the throttle cable... probably has a double nut assembly holding it in place. I would imagine you can undo these, and adjust as needed to allow the throttle to be set higher. Have you dug into the TM on this set yet?

I don’t think that works on a diesel, the speed is controlled by the governor which is weight driven with springs. So it’s either my governor spring on the run lever or the muffler is wet stacked maybe? ???

You need to read the book.

Diesel engine speed is maintained by the speed control system (Figure 3) which includes the mechanical
governor, governor lever, RUN lever, and STOP lever. The system is designed to maintain engine speed under
load at a constant rate of between 3,570 and 3,630 rpm (no load speed of 3,750 rpm).

The governor is the flyweight-type, with the weights mounted on a gear driven by the engine camshaft gear. The
force of the flyweights is transferred through a thrust sleeve and collar to the governor lever which is balanced
against the tension of the governor spring. The spring is stretched between the governor lever and the engine
RUN lever. When the engine speed drops below the governed speed, the resulting decrease in governor
flyweight/camshaft rotation places tension on the governor spring. The tension repositions the fuel injection pump
rack and increases the stroke of the plunger in the fuel injection pump allowing more fuel to flow to the pump
delivery valve. The increase in fuel flow causes the diesel engine to speed up. As the diesel engine recovers to
the governed speed, the governor flyweight/camshaft rotation stabilizes and the tension on the governor spring
relaxes. This changes the position of the fuel injection pump rack and shortens the stroke of the plunger allowing
less fuel to flow to the fuel injectors maintaining the engine speed at 3,600 RPM.
The governor control mechanism features two operator controlled levers. The black diesel engine RUN lever
places tension on a spring attached to the governor lever. The tension places the governor lever in a position to
allow fuel flow to the fuel injector for diesel engine start up and to allow the diesel engine to continue running after
startup. The red diesel engine shut down or STOP lever is operated by either depressing the red STOP lever or
by the low oil pressure shutdown system. When depressed, the lever trips the RUN lever releasing the tension on
the governor spring which places the governor lever in a no fuel or stop position. This action shuts off fuel flow to
the fuel injector stopping the combustion process and shutting down the diesel engine.

Guy, thanks for taking the time to post the long version. I read that..and understand that the speed is proportional to the fuel being fed. I am Not sure how to make it feed more fuel if the run/stop lever adjustment slot is at its maximum.

I just pulled the spark arrestor disc off and they were seriously full of carbon. Soaking now let you know what I get when re-installed.

Run your engine with the discs off to see if the RPM comes up. It won't hurt the machine to run without the discs.

Diesel, will do that tomorrow. Night time here. Let you know what happens

Heres the update, obviously wet stacked and slowing down the motor speed . Cleaned the disks re-installed. Running awesome at around 60.7 hz might lower the running speed just a bit on the run lever. Thanks for the help. JHO

I am really amazed that carbon buildup can cause the engine speed to slow down that much. Before it was about 53hz, and still ran fine. Still need to find the part in the TM that tells me the RPM of the engine.

3. Diesel Engine:
Manufacturer Yanmar
Model L48AE-DEG
Type Single cylinder, four cycle, naturally-aspirated diesel
Stroke 2.2 in. (55 mm)
Displacement 12.88 cu in. (0.211 liters)
Compression Ratio 19.9:1
Rating 4.2 HP @ 3,600 RPM
Engine Operating Speed - No Load 3,750 RPM
Engine Operating Speed - Full Load (±30 RPM) 3,600 RPM
Altitude Degradation, 4,000 to 8,000 ft 1.3% per 328 feet (100 m)

Read the TM. That sort of info is always in the front.