What should drop out the starter solenoid on an MEP-003a?

[MajorGasAttak]

What is or should be used to drop out the starter solenoid once the generator is running? On my MEP-003a someone added an additional oil pressure switch plumbed in line with the oil pressure gauge. While it all works fine there are times when the generator may be cold and during cranking the oil pressure comes up enough to open this second oil pressure switch which then knocks out the starter solenoid before the engine fires up. One wire from this switch comes from the control box and the other goes right to the solenoid. I can get the wire number and pictures if needed.

Thanks

 

[sewerzuk]

The device that SHOULD cut out the starter is a under small stamped metal cover, right next to the oil filter. The injection pump linkage is directly above it. It is adjustable; the TM procedure calls for a specific thickness using a feeler gauge but I have found that, if the metal contact has been bent, the thickness doesn't matter. I just adjust mine so that the starter disengages once the set is running at about 50hz. I have worked on several -002's and -003's that required this adjustment.

 

[MajorGasAttak]

Thanks, I will look into this and hopefully figure out why a second oil pressure switch was added to knock out the solenoid.

 

[MajorGasAttak]

Found the cut out switch. Made all sorts of adjustments (with and without a feeler gauge) but there is still a problem. The starter pulls out most of the times but occasional it jumps back in shortly after the gen set fires up. Makes an ugly noise when it does that. Guess I'll wire the additional oil pressure switch back to the way I got it and rely on oil pressure to retract the starter. Not worth the $250 price tag to replace the switch assembly in my eyes. The previous owner ( a police department) had it serviced by a known generator mechanical firm. Perhaps they thought this was also the best and cheapest fix too. Time will tell or at least until I install a DynaGen automatic controller.

 

[sewerzuk]

Since the "feeler gauge method" relies on the contact still being straight, I have found that it doesn't always work. If the contact has developed a "bow" in it, the numbers in the TM won't work.

I usually start the generator, use a digital frequency meter to adjust the engine speed down to around 50hz, and then adjust the speed switch. As I adjust it, I check for proper operation by quickly "bumping" the start switch. I adjust it so that it has just disengaged the starter at the 50hz engine speed. It usually works well...

But, it sounds like yours has some kind of intermittent problem. You might try working the throttle with the set running, and watching the little "button" inside of the speed switch. It should push out on the contact as engine speed rises. The speed switch is a very simple little device...it should be repairable without too much effort.

 

[MajorGasAttak]

Since the starter drops out using this second oil pressure gauge I can get by until time allows for a more thorough inspection. I did notice the "bow" you mentioned so I had little faith in the feeler gauge method.

Thanks for the input!

 

[SteveH]

What is or should be used to drop out the starter solenoid once the generator is running? On my MEP-003a someone added an additional oil pressure switch plumbed in line with the oil pressure gauge. While it all works fine there are times when the generator may be cold and during cranking the oil pressure comes up enough to open this second oil pressure switch which then knocks out the starter solenoid before the engine fires up. One wire from this switch comes from the control box and the other goes right to the solenoid. I can get the wire number and pictures if needed.

Thanks

I was thinking of installing a second oil pressure switch like this, so I could monitor pressure with the PLC during auto-start (can't use the original as it's shorted out while cranking); plan was to continue to 'crank' to flash the field for a few seconds once I had good oil pressure, but I might re-think now I know that pressure comes up early. However, it would be useful (if you have the info) what part was used where to add in the pressure switch; I was at the local autoparts stores last week and couldn't find anything with the correct threads to 'T' the connection.

-Steve

 

[sewerzuk]

I was at the local autoparts stores last week and couldn't find anything with the correct threads to 'T' the connection.

-Steve

The back of the oil pressure gauge is a -4AN fitting, IIRC. You can buy any adapter you need from Summit Racing...

 

[storeman]

Majorgas,
PM sent.
Jerry