MEP-002A just shuts off

[rcflyer70]

I'm having an issue with my normally rock solid MEP-002A...I just finished flushing out the entire fuel system to include cleaning out the fuel tank, cleaning pumps, and changing all the filters. I also changed the oil. Fuel system quickly primed and the generator started and ran without issue (I've been jump starting it for years now...got tired of replacing batteries every couple of years. Once started, I quickly remove the jumper and the generator runs rock steady for approximately one minute then it shuts down. I initially thought it could be the low oil pressure switch but it wasn't. (I removed, cleaned and verified - with it running too). The only thing out of the ordinary is that the battery charging meter show pegged out. I checked the battery leads and they only have 25.6v.
Would this issue be related to the charging system? Is there a safety circuit other than low pressure that would be shutting it down after approximately 1 minute (I've started it numerous times and it shuts down after running the same period of time).

Any help is appreciated!

 

[justacitizen]

there is a small button on the front near the 120 volt outlet. that button is the DC breaker. but i think it would have to be reset and that doesn't sound like your problem. could be the constant speed switch? is the fuel solenoid shutting down the engine?

 

[rcflyer70]

there is a small button on the front near the 120 volt outlet. that button is the DC breaker. but i think it would have to be reset and that doesn't sound like your problem. could be the constant speed switch? is the fuel solenoid shutting down the engine?

While it definitely acts like it, I didn't verify the fuel solenoid was shutting it down but will in the morning. Where is the constant speed switch physically located? Will check in the morning. Thanks for advice!

 

[rickf]

Could it be a critter nest in the air box causing an overheat condition and shutting down on overheat?

 

[Chainbreaker]

First off, you should not have to be replacing batteries "every couple years". My original MEP-002a has batteries (Interstate MT 51's with 5 yr warranties) that are now 7 years old and it starts perfectly off them. However, they have always been on battery maintainers which helps longevity.

So you are saying it shuts down once you disconnect your battery jumper source after approx. 1 minute. What happens if you leave it connected to jumper does it still run? What are the battery voltages for each battery after they have sat unused overnight?

If your battery charging meter is pegged there is either a problem with your "batteries" or "charging system" (Voltage Regulator/Rectifier [Item 7 printed pg #123 of the -24TM]. Both need to be checked.

 

[Guyfang]

Agree with Chainbreaker, but a charging problem should not shut the set down. I checked the battery leads and they only have 25.6v. What more do you want? I assume you checked at the battery's, but was it running or stopped? Was the jumpr disconnected? Or not? If I were you, I would buy a DC Volt Reg. and fix the problem.

Now, about shutting off. The only reason you MIGHT have a problem with charging and shut off is when the the DC VR is bad, and the batterys are bad/low charge. The gen set will run for a min or two in this situation. To test that, jump the set off, and leave the jumpers hooked up. If the set continues to run, then your VR AND battery's are no good. Try that first. If you still have the problem, there is THE NEXT STEP. Jumping the safety circuit.

 

[rcflyer70]

Thanks for everyone's advice. I think I've found the problem with it shutting off - the shutters were stuck shut. I disassembled and thoroughly cleaned and lubed (dry lube) everything. Once back together, all seems good. The unit runs about 10 minutes now and then shuts down. I'm thinking now the temperature sensor may be the issue. Before replacing it, I'm going to pull and clean my oil cooler just to be sure. Batteries - they were definitely bad! Looks like my DCVR is good (I have good voltage even with the jumper cable off).
Hopefully I'll have good news to report next weekend when I have an opportunity to clean the oil cooler.

Thanks again to all!

 

[Ray70]

Try putting a jumper wire across the connector for the temp switch and see if that keeps it running. If you still have issues with it shutting down, leave the jumper wires on the machine for a while and see if it stays running. It sounds like your DCVR is working, but 25V is very low, it should be up closer to 28
But... it's possible your bad batteries is pulling it down to 25V if they are completely toast!
I'm curious it your charging system is unable to keep up with the DC draw of the fuel pump and solenoid and after a while the machine runs out of fuel or runs out of power to keep the fuel solenoid pulled in. Leaving the jumpers or a battery charger on while its running will quickly determine if low DC voltage is your issue or not.

 

[Chainbreaker]

Just so you know the shutters on my units don't begin to open for several minutes. If you dissembled the shutters & cleaned/lubed them you probably already know this...That the spring actuator mechanism is controlled by a wax cartridge mechanism (Item 37 referred to as the "Power Element" shown on printed page 94 of the -24P manual) that only releases the shutters once its melted. Off the top of my head, I can't recall the temperature the wax melts at but it has to get very warm before it melts. This allows the shutters to slowly open so as to facilitate the cylinders coming up to proper combustion temperature first which aids operating efficiency in cooler operating temperatures.

Often times people not familiar with the spring loaded wax shutter operation try to pull the shutters open by hand when unit is cold and when they don't release they assume something is wrong with them when really there isn't anything wrong. Regardless if they were stuck or not, it would not cause the unit to shut down within a minute or so as you reported in your initial post. It would probably take 15 minutes or so this time of year on a cold unit for the shutters not opening to trip the high temp safety sensor to shut the unit down.

I know you said you cleaned and verified the oil pressure sensor. How did you verify it? If you have not temporarily bypassed it by jumping it you should just to insure the sender is not the culprit. It is a common point of failure once the senders get older and the symptoms you are experiencing would be expected from a faulty erratic oil pressure sensor tripping the safety cutout circuit and shutting down.

Also, you really should invest in a new set of batteries, it makes life so much easier and more reliable when unit is called into action during an outage.

 

[rcflyer70]

To check the low oil pressure switch, I removed and cleaned it. I then used approximately 15psi air pressure to verify the switch closed - it did. You have a good point about the sensor. I think I'll go ahead and replace it. New batteries will also be installed.