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A few months back I decided to purchase a MEP-802 or 803 as a fun winter project. I anticipated doing some fairly routine servicing and maybe a little more and then having a nice generator to keep on hand to run my house (all gas appliances).
I found a MEP-802A on a smaller government auction site being listed by a county government in Alabama. It was stated to have run a few years ago, but was put into storage in unknown condition. It had 5000 hours on the clock and was a 1995 Libby unit. I won the auction & pickup was a breeze.
Before going too far I wanted to make sure it ran at all. All fluids appeared drained so I serviced it with new oil, coolant and fuel. I used a 28 volt aircraft battery ( I am helicopter mechanic so there are a lot of these laying around the shop) to jump the unit. It turned over with the dead crank switch & pumped fuel on prime ( with a sizeable leak from a deteriorated return line). Went to start and it stumbled to life. I shut it down after a few seconds and since it seemed promising decided to put more time/money into it.
I pulled the covers and started working through the unit as follows:
Fuel System: Removed fuel tank & cleaned a ton of sand and gunk out of it. Installed brass bulkhead fittings to replace deteriorated well nuts. Replaced leaking gaskets on the fuel pick up, fuel quantity sender, and fuel level switch. Cleaned aux fuel pump screen and flushed those lines to the tank. Replaced the return fuel lines with gates 1/8" hose from local auto parts store. Installed a new water separator/fuel filter.
Oil: New oil filter.
Coolant: Removed radiator and flushed with hose. Degreased radiator fins as they were caked with grease/dirt. Reinstalled and flushed / ran with distilled water, repeated twice. Added new 50/50 coolant.
Electrical: I installed the MOV/fuse mod following instructions posted on the forum. I add a standard 30 amp generator plug L14-30 where the cable boot is at. I replaced the battery cables with new marine tinned cable and installed new U1R batteries.
I also reassembled with some new stainless hardware and cleaned the unit of years of accumulated soot.
I started the unit up and it ran fine. It produced power from the convenience receptacle and the new plug I had installed. I started to load test the unit using some heating elements. At a load of 3000 watts resistive it ran fine. At a load of 3500 watts resistive the rpm would immediately start to droop. It would continue to droop unless the load was removed. If the load was reduced back to 3000 watts it would slowly recover and run fine at 3000 watts. If the load was not removed it would eventually stumble and shut off. No warning lamps were illuminated. The exhaust was clear when it would droop. No smoke of any kind.
Since the exhaust was clear I assumed I had a fuel issue. For some reason it was not getting enough fuel to maintain RPM at load. I decided to do the simple (cheap) things first. I replaced the final fuel filter (cartridge style adjacent to the injection pump rail) and air filter with no change in symptoms. I then removed both injectors and cleaned them using an ultrasonic machine (they were absolutely filthy inside, I was surprised it ran as well as it did). I reinstalled the injectors and still had the same issue. I tested the flow out of the electric fuel pump. Seemed fine, even when I simulated a restriction. Swapped in the aux pump with no change to the symptoms.
I was wondering at this point if the injection pumps were pumping adequately, if I had screwed up the injectors by disassembling and cleaning them or if there was an issue with the governor system. I assumed the governor system was fine because it started, turned off and adjusted to some load adequately. The stop lever screws were also safety wired with a lead bulla (seal) so I assumed this meant that no one had messed with it since the factory had set it.
I disassembled each injector pump (taking them out one at a time). Both seemed to operate freely and push fluid out. They were extremely clean. With a pump out I could see the rail which controls the fuel pumps move freely with changes to the stop lever. I reinstalled the pumps and figured the injectors must be bad or I screwed them up somehow. I also thought the pumps could still be bad.
While thinking about my next step I saw a power plant trailer with two 802s come up on the big government site. In need of some parts to troubleshoot with, I decided to bid on it and then sell the two generators when I was done troubleshooting. Not sure this was great logic, but I won the auction and now have three... The two from the trailer were both reset units with about 3 hours on them. Both produced power and ran a 100% indicated load no problem. Great! I immediately pulled injectors off one unit to go on the original, 'bad' unit.
The 'new' injectors did not solve the problem. I intended to swap injection pumps next, but figured I would look into the governor settings first. I was confident the fuel control rail was moving as it should based on forum searching, photos, videos online, and reading the manuals. I did not know if it was moving far enough or if the injection pumps were clocked (rotated counter-clockwise per the manual) correctly. Some videos/users reported that a notch or two in the clockwise direction helped them with some fueling issues (at the risk of the machine not turning off/running away).
I also found a factory engine service manual via this forum which talked about a 'G setting' and a tool. This is the thread I found for the tool: https://www.steelsoldiers.com/threa...do-you-do-it-tm-mentions-a-gage.182962/page-2
That thread gave me the dimensions for the tool and the manual had instructions of how to use it to confirm the governor setting for rpm droop compensation. I did not want to remove the front cover to fully follow the manual procedure so I made some assumptions and came up with something that in the end worked out. Your mileage may vary. This is not how it is supposed to be done, but its how I did it that day and it worked.
The stop lever has a top and a bottom screw. Based on my estimations the top screw was a stop for the off position and the bottom screw was a stop for 'wide open throttle' or maximum fuel. I cut the saftey and backed the top screw all the way until it bottomed out (as short as possible). I then loosened the forward injection pump a bit, just a little looser than snug on the nut. I manually moved the stop lever from off to on and observed the forward pump and felt for resistance from the fuel control rail. When moved towards the stop position you can feel when the fuel rail stops moving freely because it has moved the fuel pump to its maximum travel. You can also see it try to rotate the slightly loose pump. I took this lever position to be the correct "off" setting and moved the upper screw out (making it longer) unit it contacted the lever. I had to fool around a little to be certain I was getting full movement of the rail but the also ensure the rail would not 'over travel'. It was a bit of a balancing act, but no big deal. This whole part of the procedure is NOT in the manual. This may all be fake news.
Now following the manual / this forum I made the G setting tool out of a scrap sheet of aluminum. Basically its just a block to let you make a setting by holding things in the right place instead of measuring. You could absolutely get close with a mm ruler. I placed the tool on the top screw as called out in the manual and adjusted the bottom screw until the stop lever contacted the tool as indicated in the manual. I safetied the stop screws and re-assembled the unit with original injectors.
The unit ran perfectly and also shut down properly! I then load tested it and it will crank out 100% indicated load no problem. I applied a load of 6,300 watts resistive and it ran it no problem. I then let it run a load of 5,000 watts for 12 hours. It ran it with no problems.
That is the saga. Moral of the story: do not assume that 'factory looking' things are actually factory or the factory did their job correctly. I find it a bit hard to believe that it was mis-assembled in 1995 and ran for 5000 hours without someone trying to fix this issue. But hey. I learned stuff and was entertained for a few weeks. Now its a great generator!
I found a MEP-802A on a smaller government auction site being listed by a county government in Alabama. It was stated to have run a few years ago, but was put into storage in unknown condition. It had 5000 hours on the clock and was a 1995 Libby unit. I won the auction & pickup was a breeze.
Before going too far I wanted to make sure it ran at all. All fluids appeared drained so I serviced it with new oil, coolant and fuel. I used a 28 volt aircraft battery ( I am helicopter mechanic so there are a lot of these laying around the shop) to jump the unit. It turned over with the dead crank switch & pumped fuel on prime ( with a sizeable leak from a deteriorated return line). Went to start and it stumbled to life. I shut it down after a few seconds and since it seemed promising decided to put more time/money into it.
I pulled the covers and started working through the unit as follows:
Fuel System: Removed fuel tank & cleaned a ton of sand and gunk out of it. Installed brass bulkhead fittings to replace deteriorated well nuts. Replaced leaking gaskets on the fuel pick up, fuel quantity sender, and fuel level switch. Cleaned aux fuel pump screen and flushed those lines to the tank. Replaced the return fuel lines with gates 1/8" hose from local auto parts store. Installed a new water separator/fuel filter.
Oil: New oil filter.
Coolant: Removed radiator and flushed with hose. Degreased radiator fins as they were caked with grease/dirt. Reinstalled and flushed / ran with distilled water, repeated twice. Added new 50/50 coolant.
Electrical: I installed the MOV/fuse mod following instructions posted on the forum. I add a standard 30 amp generator plug L14-30 where the cable boot is at. I replaced the battery cables with new marine tinned cable and installed new U1R batteries.
I also reassembled with some new stainless hardware and cleaned the unit of years of accumulated soot.
I started the unit up and it ran fine. It produced power from the convenience receptacle and the new plug I had installed. I started to load test the unit using some heating elements. At a load of 3000 watts resistive it ran fine. At a load of 3500 watts resistive the rpm would immediately start to droop. It would continue to droop unless the load was removed. If the load was reduced back to 3000 watts it would slowly recover and run fine at 3000 watts. If the load was not removed it would eventually stumble and shut off. No warning lamps were illuminated. The exhaust was clear when it would droop. No smoke of any kind.
Since the exhaust was clear I assumed I had a fuel issue. For some reason it was not getting enough fuel to maintain RPM at load. I decided to do the simple (cheap) things first. I replaced the final fuel filter (cartridge style adjacent to the injection pump rail) and air filter with no change in symptoms. I then removed both injectors and cleaned them using an ultrasonic machine (they were absolutely filthy inside, I was surprised it ran as well as it did). I reinstalled the injectors and still had the same issue. I tested the flow out of the electric fuel pump. Seemed fine, even when I simulated a restriction. Swapped in the aux pump with no change to the symptoms.
I was wondering at this point if the injection pumps were pumping adequately, if I had screwed up the injectors by disassembling and cleaning them or if there was an issue with the governor system. I assumed the governor system was fine because it started, turned off and adjusted to some load adequately. The stop lever screws were also safety wired with a lead bulla (seal) so I assumed this meant that no one had messed with it since the factory had set it.
I disassembled each injector pump (taking them out one at a time). Both seemed to operate freely and push fluid out. They were extremely clean. With a pump out I could see the rail which controls the fuel pumps move freely with changes to the stop lever. I reinstalled the pumps and figured the injectors must be bad or I screwed them up somehow. I also thought the pumps could still be bad.
While thinking about my next step I saw a power plant trailer with two 802s come up on the big government site. In need of some parts to troubleshoot with, I decided to bid on it and then sell the two generators when I was done troubleshooting. Not sure this was great logic, but I won the auction and now have three... The two from the trailer were both reset units with about 3 hours on them. Both produced power and ran a 100% indicated load no problem. Great! I immediately pulled injectors off one unit to go on the original, 'bad' unit.
The 'new' injectors did not solve the problem. I intended to swap injection pumps next, but figured I would look into the governor settings first. I was confident the fuel control rail was moving as it should based on forum searching, photos, videos online, and reading the manuals. I did not know if it was moving far enough or if the injection pumps were clocked (rotated counter-clockwise per the manual) correctly. Some videos/users reported that a notch or two in the clockwise direction helped them with some fueling issues (at the risk of the machine not turning off/running away).
I also found a factory engine service manual via this forum which talked about a 'G setting' and a tool. This is the thread I found for the tool: https://www.steelsoldiers.com/threa...do-you-do-it-tm-mentions-a-gage.182962/page-2
That thread gave me the dimensions for the tool and the manual had instructions of how to use it to confirm the governor setting for rpm droop compensation. I did not want to remove the front cover to fully follow the manual procedure so I made some assumptions and came up with something that in the end worked out. Your mileage may vary. This is not how it is supposed to be done, but its how I did it that day and it worked.
The stop lever has a top and a bottom screw. Based on my estimations the top screw was a stop for the off position and the bottom screw was a stop for 'wide open throttle' or maximum fuel. I cut the saftey and backed the top screw all the way until it bottomed out (as short as possible). I then loosened the forward injection pump a bit, just a little looser than snug on the nut. I manually moved the stop lever from off to on and observed the forward pump and felt for resistance from the fuel control rail. When moved towards the stop position you can feel when the fuel rail stops moving freely because it has moved the fuel pump to its maximum travel. You can also see it try to rotate the slightly loose pump. I took this lever position to be the correct "off" setting and moved the upper screw out (making it longer) unit it contacted the lever. I had to fool around a little to be certain I was getting full movement of the rail but the also ensure the rail would not 'over travel'. It was a bit of a balancing act, but no big deal. This whole part of the procedure is NOT in the manual. This may all be fake news.
Now following the manual / this forum I made the G setting tool out of a scrap sheet of aluminum. Basically its just a block to let you make a setting by holding things in the right place instead of measuring. You could absolutely get close with a mm ruler. I placed the tool on the top screw as called out in the manual and adjusted the bottom screw until the stop lever contacted the tool as indicated in the manual. I safetied the stop screws and re-assembled the unit with original injectors.
The unit ran perfectly and also shut down properly! I then load tested it and it will crank out 100% indicated load no problem. I applied a load of 6,300 watts resistive and it ran it no problem. I then let it run a load of 5,000 watts for 12 hours. It ran it with no problems.
That is the saga. Moral of the story: do not assume that 'factory looking' things are actually factory or the factory did their job correctly. I find it a bit hard to believe that it was mis-assembled in 1995 and ran for 5000 hours without someone trying to fix this issue. But hey. I learned stuff and was entertained for a few weeks. Now its a great generator!
