MEP-16A Output problem

[WWIILBird]

I'm having issues with power output and looking for advice. I recently purchased my generator which starts right up and runs great (new carb, plugs, etc). After I let it warm up a bit and I get it settled on 60Hz and volts where they should be (gen is mounted on a light tower trailer) I turn on one 1,000 watt light at a time and wait a minute, then turn on the next, wait a minute, then turn on the last one. All looks good at this point.

Here's the thing, you can hear the engine slow very slightly as the loads come on which I don't think is unusual so I bump up the throttle to full and while the lights (Metal Hallide) warm up things are still good and all three bulbs are getting brighter but then after about 4-5 minutes one or two bulbs start to develope a little flicker as they get brighter. At the same time I watch the hertz meter start going south of 60Hz and pegs at 55 (all the way to the left) while the load meter builds to around 75%. Then one light goes out, then the next, the third stayed on with no flicker. I didn't notice the engine pick up as if a load was shed so I guess the two lights that went off were still trying to pull power, I did notice as I turned off the breaker the engine started to race so I backed off the throttle a bit.

I'm guessing it's not getting enough juice so the capacitors or something is causing the lights to shut down. About a month ago I hooked up my civy gen 7,200 kw 8,200 peak and ran the lights for almost an hour with no issues.

Is there anything I can adjust that would avoid this?

Thanks Nick

 

[Carl_in_NH]

Not being able to maintain frequency sounds like a governor issue. You might see a change of a few Hz from no load to full load without touching the throttle, but it shouldn’t drop off the scale when loaded, nor should it race when the load is removed.

Now, frequency should have no first order effect on whether the lights keep working – but I’m guessing that when you’re losing the lights there’s a problem with the regulator and its ability to maintain sufficient field current to sustain the proper output voltage. What does the output voltage do during the time when the lights start getting brighter and then go off?

 

[Carl_in_NH]

One other thought; is your 24V battery up to snuff? I'm speculating that if it is not, or perhaps your 24V battery charging system isn't working, then your generator might have trouble maintaining field current at full load and causing the output voltage to drop or fail. Just a guess.

 

[WWIILBird]

While the volts appear steady at first, as the Hz drop and the load meter starts to rise, the volts start to drop down to about 100 where it stays. I've turned up the variable resistor but that doesn't seem to do anything.

Regarding the battery, I took two 12v motor cycle batteries put them in series and mounted a plastic box on the trailer. One wire goes to the starter and the other is connected to the ground wire behind the slave recepticle. My plan was to use my duece 24V trickle charger from time to time to juice up the batteries since their not being charged..

 

[Carl_in_NH]

Your battery should be charged when the genset is running; there’s a DC charger circuit that should accomplish the task of maintaining the battery charge.

Sounds like we’re on the right track WRT the voltage output failing – you’ve either got soft batteries that aren’t being charged, or a regulator problem, or perhaps a bad wire or dirty connection to the alternator field winding. You might even have a problem with the alternator that’s causing it not to be able to supply full output; if this were the case, then the regulator wouldn’t be able to make the alternator output full power and maintain voltage even at full field current. It might be interesting to reduce the load a little – by only powering up two of the light bulb loads – and see if it can maintain output. If so, then it needs further investigation.

I believe you’ve got two separate and distinct issues with this genset; one is a fuel delivery / filter or governor issue that’s causing trouble maintaining frequency, and the other is related to the output voltage regulation under load. Troubleshoot them one at a time and you’ll likely cover ground faster.

 

[Recovry4x4]

If this is an MEP-016A or C genset, it has no charging circuit for self starting. These were mostly pull starts but the mis standard starter fits and there is a start kit for it. Firstly, do not idle the genset, it will fry a transistor in the regulator. Why they put the governor override on these, I don't know. If the frequency is falling at WOT then the engine may be losing power. I had one of these do this and found out that the engine was just worn out and didn't have the power. None of mine are ever run below WOT for moore than a couple of seconds.

 

[Carl_in_NH]

Sorry about being misleading on the charging of the battery; I was under the mistaken impression that all MEP units had the ability to charge their own battery.

 

[WWIILBird]

I attached a couple of pictures of the top of the engine, I'll run up the engine with two lights this morning to see what happens and post. What does WOT mean? Also, I've read the technical manual and see it say's set to govern. On the metal tab next to the govern knob I see it says "start" with an arrow to the left and "govern" I am assuming to the right as I can't see the arrow. The TM says put govern know on run or govern. Not consistent with tab. One thing I don't understand is that when I move the govern knob to the right what's supposed to happen. I'll assume it will throttle up and down with load. Thanks again.

 

[Carl_in_NH]

WOT == Wide Open Throttle.

You want the control all the way in the 'govern' position - that should allow the engine to spool up to the point where the governor takes over control.

 

[PeterD]

On those lights, consider the possibility that the metal halide lights are frequency sensitive. Much like sodium lamps, they can get really unhappy if the frequency is wrong, as the ballast inductor is 'tuned' for 60 Hz. They'll handle a few Hz off, but if you go too far, things get flaky.

 

[jbk]

you say you put a new carb. on. you may just need to adjust the main jet, its not fixed. refer to the tm. i do know on mine when i put 4 kw on it just a half a turn one way or the other made the differance of maintaining the engine speed or slowing down. also be sure all 4 cyl. are firing. pull all the plugs after you run it and be sure none are wet.

 

[WWIILBird]

Ran the generator today and adjusted the speed adjustment screw and governor spring adjustment. I pegged the frequency gage right on 60Hz and it appeared the governor was working. Then fired up one light then the next. All looked good no flickers in the lights and the guages were where they should be and load at about 50%. Then I flipped the breaker on the last light after about 10 minutes. After about a minute or two the Hz meter dropped to the left side and the volts dropped to just below 100 and one light went out. Since it seemed to be running at maximum I'm thinking this gen just doesn't have the juice anymore unless there is something else I can tweak or tighten.

 

[WWIILBird]

I'll read the TM and try the carb tomorrow.

 

[jbk]

you want to set the freq. no load 61.8. warm the set introduce your load and make the adjustment to the main jet.

 

[WWIILBird]

Does anyone have a copy of TM 5-2805-203 manual for engines. I don' t see it in the reference section. Not sure which is the main jet on the carb. I see a screw and a T handle. Thanks

 

[jbk]

the tm you need is5-2805-203-14 with unit off seat main then turn counterclockwise 3/4 of a turn. yes that is it on the bottom side of carb. with the t handle. turn idle needle its on top left side of carb. counterclockwise off seat one half turn. then crank it up apply load and adjust the main. if the unit stumbles when load is removed adjust idle mix needle.

 

[WWIILBird]

Follow up, more fresh gas, I took the fuel filter apart and the screen was spotless. I then took the carb off and took it apart expecting to see some gunk. The carb was clean. Put it back together and followed the TM for adjusting and started it. The engine runs real strong and guages are right on the mark. Introduced one light again, then the next, then the third. This time everything was right on the money until about three or four minutes maybe alittle longer and I hear start to slow again and it setttles in at just below 100 volts and the Hz drops to the left side, then one light goes out. ****, here we go again. It can handle two lights no problem. When there is no load you can race the engine really fast and the Hz needle swings all the way to the right. So I don't know...

 

[PeterD]

Can you find out what the power factor on those lights is? I wonder if a really bad power factor is perhaps part of the problem?

 

[mdlbldrmatt135]

Is the float swelling?? Ethanol in gas is known to casue the floats (some kind of foam) to swell in these carbs. I'm getting close to running a test with a coated one vs a new "custom made" one using a Oregon 49-009 and making a new pivot to get it to fit into the carb.

I've also read that Sta-bil Marine formula can help counteract the Ethanol in the gas as well.

 

[WWIILBird]

Thanks guys, the lights are 1,000watt metal hallide bulbs as called for in the TM. Is this what you mean by load factor? Help me on the float, when I took apart the carb (4 screws) there was a round hard off white or yellowed plastic "donut" shaped part that had clearance around its sides. It didn't appear to be sticking to anything. I gave it a good shot of gumout. I should add when I started turning off the breakers one at a time the engine picked up more speed with each breaker I turned off and the dials settled back on the original correct settings . The whole time I stared at the top of the generator and the throttle was wide open and I never noticed anything move while it lost speed or regained it.