MEP-805A going into Overspeed

[Billy2642]

So I have an 805A that has 9 hours on it after tier 2 reset. When I start it, it immediately goes into over speed and shuts down. It doesn’t seem like it’s running at the 2200 RPM mark that the manual says for Overspeed threshold. I have checked the MPU which shows 2.2 VAC. I did not take the MPU out for inspection as it was reading within specs.I have replaced all the relays under the panel just to be sure and no change. All connections are not corroded as far as I can see. Any ideas on where else I can look?

 

[Evvy Fesler]

So I have an 805A that has 9 hours on it after tier 2 reset. When I start it, it immediately goes into over speed and shuts down. It doesn’t seem like it’s running at the 2200 RPM mark that the manual says for Overspeed threshold. I have checked the MPU which shows 2.2 VAC. I did not take the MPU out for inspection as it was reading within specs.I have replaced all the relays under the panel just to be sure and no change. All connections are not corroded as far as I can see. Any ideas on where else I can look?

@Billy2642, does it run long enough to produce voltage at either the convenience outlet or line outputs?

 

[Billy2642]

@Billy2642, does it run long enough to produce voltage at either the convenience outlet or line outputs?

Yes it does produce voltage. I took a short video of it running but don’t see how to post it. When it runs it’s surging some. I’ll see if I can post the video on the original

 

[Billy2642]

Yes it does produce voltage. I took a short video of it running but don’t see how to post it. When it runs it’s surging some. I’ll see if I can post the video on the original

MEP-805A Overspeed and Surge

youtube.com

hopefully this link works for the video

 

[Evvy Fesler]

MEP-805A Overspeed and Surge

youtube.com

hopefully this link works for the video

If you have OneDrive, DropBox, Google Drive or iCloud Drive you can put the video there and get a link and post it here. LOL - YouTube works too... doh Evvy!

 

[Evvy Fesler]

If you have OneDrive, DropBox, Google Drive or iCloud Drive you can put the video there and get a link and post it here. LOL - YouTube works too... doh Evvy!

I couldn't see the line voltage meters on the control panel. Are they indicating something? Have you done PM on it yet? Fuel filter, etc.?

 

[Billy2642]

I couldn't see the line voltage meters on the control panel. Are they indicating something? Have you done PM on it yet? Fuel filter, etc.?

voltage meter is reading as it should and adjustable up and down. PM complete. The only thing is I’m starting/running off slave cable from another 805A. Would that make a dofference?

 

[Evvy Fesler]

Doubtful. It sounds like a fuel problem. If you're sure your filter is new then you might check the tubing, water separator, and ultimately the flow to the injectors. Check clamps on hoses to make sure they're tight and not admitting air.

 

[kloppk]

It may be that the Governor Controller needs to be adjusted or possibly it's bad.
There is an adjustment procedure in the -24 for adjusting it. It could be its adjusted to be a bit too aggressive and is overshooting and undershooting the target RPM of 1,800 RPM thus causing the oscillation in RPM.

 

[Billy2642]

It may be that the Governor Controller needs to be adjusted or possibly it's bad.
There is an adjustment procedure in the -24 for adjusting it. It could be its adjusted to be a bit too aggressive and is overshooting and undershooting the target RPM of 1,800 RPM thus causing the oscillation in RPM.

I will have to look for that procedure in the -24. Here’s a pic of the controller although I have no idea if you can tell anything from it

 

[Ray70]

In addition to the -24 manual that Kurt mentioned there is another TM that Guy has posted on page 2 in the Generator TM section ( 4th listing down ) that also explains a bit about adjusting the GCU on your machine.
You could try turning the gain control counter clockwise a bit, but it might be best to review the entire GCU test and adjustment procedures and go from there.

 

[87cr250r]

Revs up and trips immediately? That sounds like the speed setting is too high. In the above picture, it's the blue "freq" potentiometer on the left.

 

[loosegravel]

Revs up and trips immediately? That sounds like the speed setting is too high. In the above picture, it's the blue "freq" potentiometer on the left.

I'm not sure if it applies here, but in my experience with the MEP-8XX series generators they have all had issues similar to this at start-up which can be rectified by simply holding the master switch in the start position for 3-5 seconds after the engine starts. No worries, the starter will disengage. Worth a try?

 

[Evvy Fesler]

I've been loosely tracking this because I've been distracted by Thanksgiving preparations. Did I miss that the fuel flow has been thoroughly check to insure that it arrives at the injectors clean, free of air, and at the correct pressure and spray pattern?

How about the suggested governor test procedure? Did that get done?

Sorry all.. playing catch up... please ignore me if these things have been done.

 

[Billy2642]

I've been loosely tracking this because I've been distracted by Thanksgiving preparations. Did I miss that the fuel flow has been thoroughly check to insure that it arrives at the injectors clean, free of air, and at the correct pressure and spray pattern?

How about the suggested governor test procedure? Did that get done?

Sorry all.. playing catch up... please ignore me if these things have been done.

I’ve been out of the loop myself with the holidays and flu. Finally got back out there today. Fuel flow was perfect. I could manually run the injection pump once I disconnected it from the governor it it ran flawlessly. I then hooked it back up and started testing the gcu. I could get it to run by adjusting the gain but then when it would start up and the initial rpm run up would trip the Overspeed. I turned the gain all the way down which helped but it was still oscillating. I then took the mpu out and although it tested well, it had a slight knick in the tip so I replaced it. That took most of the oscillating out of but would still hit Overspeed. I then went into the TM again and looked up the adjustment procedure for the injection pump arm to the governor. Shortened that rod up a bit and now it runs perfect!!! Frequency knob adjusts from about 57hz to 62hz according to the gauge and doesn’t trip the Overspeed. On to the next!!

 

[Evvy Fesler]

I’ve been out of the loop myself with the holidays and flu. Finally got back out there today. Fuel flow was perfect. I could manually run the injection pump once I disconnected it from the governor it it ran flawlessly. I then hooked it back up and started testing the gcu. I could get it to run by adjusting the gain but then when it would start up and the initial rpm run up would trip the Overspeed. I turned the gain all the way down which helped but it was still oscillating. I then took the mpu out and although it tested well, it had a slight knick in the tip so I replaced it. That took most of the oscillating out of but would still hit Overspeed. I then went into the TM again and looked up the adjustment procedure for the injection pump arm to the governor. Shortened that rod up a bit and now it runs perfect!!! Frequency knob adjusts from about 57hz to 62hz according to the gauge and doesn’t trip the Overspeed. On to the next!!

Wonderful, thanks for the follow up!