Introduction and a question about my MEP 802a

[Summerpaws]

First, thank you for such a great resource of information on these generators! I've spent hours reading threads and learning about these generators. I live in Southern NH and am a retired fleet mechanic. I wanted a good diesel generator that would outlast me. This thing is awesome and has worked trouble free so far.
I have the generator wired into a mechanical transfer switch. It has worked perfectly, supplying all the clean power I need when the lights go out. Normally when I start it, I pull out the red knob, turn the switch to prime and then to start. Today I was showing it to my son and when I went to start it, I turned the knob to prime and I did not hear the pump. I turned it to start and it fired right up and ran normally. After a few minutes, I shut it down then turned the knob to prime to see what happened and the pump came on. I looked though the wiring schematic to see if there was a pressure switch and didn't see one. My first guess is bad (dirty) contacts on the rotary switch but I figured I would check with the experts first.

 

[Jeepadict]

I would start with a can of Deoxit to the internals of every rotary switch on and behind the control panel, exercise the switch liberally between doses of spray...batteries disconnected of course. You should feel a notavle difference of internal friction before & after. It's absolute magic sauce for contacts!

Note: to spray inside the big rotary contact switch behind the control panel requires opening the roof/lid panel.

Sent from my SM-G970U using Tapatalk

 

[Summerpaws]

I would start with a can of Deoxit to the internals of every rotary switch on and behind the control panel, exercise the switch liberally between doses of spray...batteries disconnected of course. You should feel a notavle difference of internal friction before & after. It's absolute magic sauce for contacts!

Note: to spray inside the big rotary contact switch behind the control panel requires opening the roof/lid panel.

Sent from my SM-G970U using Tapatalk

I have some of that stuff! I have the D5. Same thing?

 

[Jeepadict]

Google says Deoxit D5 is for switches/contacts.

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[Summerpaws]

Google says Deoxit D5 is for switches/contacts.

Sent from my SM-G970U using Tapatalk

That's what I have used it for. My feeble brain seems to remember they made different concentrates. We're expecting a snowstorm tomorrow but I will treat the rotaries as soon as I can and report back.

 

[2Pbfeet]

That's what I have used it for. My feeble brain seems to remember they made different concentrates. We're expecting a snowstorm tomorrow but I will treat the rotaries as soon as I can and report back.

They (Craig labs) do make several different concentrations, so I think that the old brain isn't so feeble. The D5 is 5%, though they also make several 100% versions (different applicators).

DeoxIT D-Series page with shop - CAIG

DeoxIT® D-Series contact cleaner dissolves oxides and sulfides that form on metal surfaces. This restores the contact’s integrity and leaves a thin microscopic layer that protects the metal. Special additives improve conductivity and prevent dissolved oxides from re-attaching, keeping them in...

caig.com

The D5 should do what you need, squirt it in, and with the power off, exercise the switch(es) gently. Have a look on the web for how a rotary switch goes together to help you understand where to spray. If it were me, I might double check for loose screws or wires while I was in there, just in case.

Good luck with the snowstorm.

All the best,

2Pbfeet

 

[Summerpaws]

They (Craig labs) do make several different concentrations, so I think that the old brain isn't so feeble. The D5 is 5%, though they also make several 100% versions (different applicators).

DeoxIT D-Series page with shop - CAIG

DeoxIT® D-Series contact cleaner dissolves oxides and sulfides that form on metal surfaces. This restores the contact’s integrity and leaves a thin microscopic layer that protects the metal. Special additives improve conductivity and prevent dissolved oxides from re-attaching, keeping them in...

caig.com

The D5 should do what you need, squirt it in, and with the power off, exercise the switch(es) gently. Have a look on the web for how a rotary switch goes together to help you understand where to spray. If it were me, I might double check for loose screws or wires while I was in there, just in case.

Good luck with the snowstorm.

All the best,

2Pbfeet

Thanks. When I do the job I'll check all connections. I have all the TMs including the wiring schematics so I'll chase as many as I can get to. I went out and checked the fluids today just in case I need the thing tonight. For giggles, I pulled the E stop and rotated the switch to prime. Nothing...but 3 seconds later the pump came on. I was just about to wiggle the switch. Sounds like contacts. I've dealt with many a rotary switch. I had knuckle booms and man lifts in my fleet run by gorillas so I've had some quality time with them. I'll report back.

It's rained all day today but just changed to snow. Now they are calling for 2 to 4 inches instead of 10 to 12. I'll see who's right in the morning.

 

[Ray70]

What does the primary fuel pump mounted to the left of the radiator look like?
Is it a square body or round?
If cleaning your switches etc. doesn't solve the problem, I'd suspect the pump itself.
If it's a square body Facet pump I would either replace it now, or at least buy a replacement to have on hand because it WILL die at the worst possible moment.
you can get an Airtex E8131 or E8135 to have on hand when that day comes.

 

[Summerpaws]

What does the primary fuel pump mounted to the left of the radiator look like?
Is it a square body or round?
If cleaning your switches etc. doesn't solve the problem, I'd suspect the pump itself.
If it's a square body Facet pump I would either replace it now, or at least buy a replacement to have on hand because it WILL die at the worst possible moment.
you can get an Airtex E8131 or E8135 to have on hand when that day comes.

Thank you, Ray! Of course it is the square one. I will order a replacement today.

 

[Guyfang]

Take a picture of the S1 start switch, and post it here. The Mk1 switch is very unreliable. The Mk2 switch is not much better. The Mk3 switch is nuke proof.

 

[Summerpaws]

Take a picture of the S1 start switch, and post it here. The Mk1 switch is very unreliable. The Mk2 switch is not much better. The Mk3 switch is nuke proof.

Will do Guy. Depending on weather, I'll pop the top cover off tomorrow or Wednesday. My luck, it will be the Mk1. I posted a picture of the transfer pump from my phone and it didn't go through. I'll get that sorted out today. I went through Safari instead of Tappatalk.

 

[Summerpaws]

Just had to figure out how to post the pictures. Here is a picture of the fuel pump as well as the S1 switch.

 

[Guyfang]

Mk1 It could be the problem. Need to test it. Its 00:36 and I am going to bed. Look in the TM or maybe @kloppk or someone will jump in. If not, morning is just a few hours away!

 

[kloppk]

For reliability you ought to replace, or at least have spares on hand of the better versions of the primary fuel pump and the S1 switch.
That S1 switch shaft is plastic and frequently snap off. That's the way my 803 came from auction. Replaced it with the all metal bullet proof 75902LV.
The "cube" Facet primary fuel pumps a quite failure prone. The Airtex E1074 was the upgrade but they are extremely hard to find. There are a couple of generic 24 volt Airtex fuel pumps people seem to have good luck with. Just need the correct fittings to plumb them in.

 

[Summerpaws]

Just my luck! Thanks for the numbers. I'll finish my testing and determine what is causing my issue but I will replace both the S1 and the pump. It seems like the Airtex E8131 is a very common and inexpensive pump. The E8135 is a bit harder to find. I understand that the 8135 is more of a bolt on replacement?

Who makes the cube rotary switch?

 

[Summerpaws]

Just my luck! Thanks for the numbers. I'll finish my testing and determine what is causing my issue but I will replace both the S1 and the pump. It seems like the Airtex E8131 is a very common and inexpensive pump. The E8135 is a bit harder to find. I understand that the 8135 is more of a bolt on replacement?

Who makes the cube rotary switch?

Nevermind. Found it. Electroswitch. Pricey bugger!

 

[Ray70]

Both Airtex pumps will work and are identical in form/fit. Just 1 is a slightly higher pressure than the other if I recall.
The fittings out of the Facet Cube will fit into the Airtex pump, just keep an eye on flow direction and all will work out good.
You have to cut the plug off the old pump and crimp or solder it onto the new pump.

 

[Summerpaws]

Both Airtex pumps will work and are identical in form/fit. Just 1 is a slightly higher pressure than the other if I recall.
The fittings out of the Facet Cube will fit into the Airtex pump, just keep an eye on flow direction and all will work out good.
You have to cut the plug off the old pump and crimp or solder it onto the new pump.

Got it. Thanks Ray. I prefer soldering/heat shrink. I think I will post on the forum that I'm looking for an S1. $230+ for the 75902 switch can't get snuck past the wife. I'm sure someone will have the newer switch. Even if the pump and contact cleaning fixes my issue, I want a spare.

 

[Guyfang]

There is one for 85 bucks in U.S. Ebay. Used. But I dont see the knob, and a few screws are missing. I would write him a mail and ask about that.

Electroswitch 75902LV Rotary Switch for sale online | eBay

Find many great new & used options and get the best deals for Electroswitch 75902LV Rotary Switch at the best online prices at eBay! Free shipping for many products!

www.ebay.com

 

[Summerpaws]

I figured I would give a quick update. Before I did anything I disconnected and charged both batteries. While they were disconnected I removed S1 and sprayed it down with DeoxIT. Replaced it and reconnected the batteries. Turning S1 to Prime and I still got a 5 second delay. Next I disconnected the Facet fuel pump (E2) and tested the voltage at the plug. 23.8 volts. Checked the batteries and had 24.8 so losing voltage. Possible bad contacts on S1...however there is no change in voltage when S1 is in Aux Fuel position. My next step will be to measure voltage at S1 at terminals 3 and 5. I'll also measure at terminal 6 to make sure I'm getting 24 volts to S1. If those are good I will follow the schematic. It looks like it goes through the normally closed contacts of K12. I see a few taps off of the line that I will be able to test. Tomorrow I am going to run direct power from the batteries to E2 and see if it comes right on. One final hint towards the healther of the fuel pump is when I switched S1 to Prime, I heard the fuel pump make a very quiet noise before it kicked on. Could it be low voltage or a bad pump? I am leaning towards a bad pump because I cant imagine a pump would stop running down 1 volt. Searching for the Airtex pump I found them hard to find in stock unless I wanted a chinese knockoff. I did find a Carter pump with the same specs. Part number P74018 24volt. Has anyone used one of these?