MEP-802A Popping CB1 as Soon as the Unit is Switched to Pump/Prime

[Ray70]

You won't be doing anything with the diags plug to troubleshoot this problem.
If I understand you correctly, when you disconnect 136D from S1 the CB no longer pops, but that's simply because you have disconnected power to the CB.
Best bet like LITD said is unplug everything 1 by 1 until it no longer pops when S1 is on.
Disconnect fuel pumps ( both )
then float sensor
lastly fuel pump module.
If its still popping the breaker you will then need to verify wiring and look for chaffed wires, but start by isolating every item downstream from CB1 one piece at a time.

 

[Blockwarden]

are you sure the CB is good? It's rare but I have had it happen before. Fast and dirty test: get a fuseholder and 7.5 amp automotive fuse and jump the cb (make sure the cb is in the open position) fuse blows you have a short somewhere it doesn't blow and you have a bad cb.

When I touch the wire to the contact on CB1 there is a pretty nasty arc that reeks of a dead short somewhere. Just occurred to me that I can try a OHM reading on output wires from SW1 to ground, if I hit "0" (or close) there is a short in the outbound wire or the destination part?

Good idea though. I have fuse holders kicking around.

 

[loosegravel]

I posted this item on another thread this morning. They’re great for doing exactly what you guys are talking about…finding dead-shorts.https://www.googleadservices.com/pagead/aclk?sa=L&ai=DChcSEwj_nvuIlv_-AhUUIK0GHehTAukYABAIGgJwdg&ohost=www.google.com&cid=CAASJeRo6vrphlYp1tS2wANeZ1SoTcYvA8ttOiJe6-QQhc-bi3bjodM&sig=AOD64_1egRNycMhUTFEuzQpWbY-jxIQTog&ctype=5&q=&ved=2ahUKEwi_6fOIlv_-AhXfATQIHYVCAiYQwg8oAHoECAQQDA&adurl=

 

[loosegravel]

Let’s try that again https://www.googleadservices.com/pa...5e3smf_-AhULIDQIHfWIBj0Qwg8oAHoECAQQDA&adurl=

 

[kloppk]

You might want to try wiring a 24 volt light bulb in place of CB1.
If the bulb is illuminated you still have a short. You can then disconnect various wires in the 24 V power wiring until the bulb goes dark. That way you'll see when you've found the path with the short and not go thru a bucket of fuses.

 

[Light in the Dark]

I posted this item on another thread this morning. They’re great for doing exactly what you guys are talking about…finding dead-shorts.https://www.googleadservices.com/pagead/aclk?sa=L&ai=DChcSEwj_nvuIlv_-AhUUIK0GHehTAukYABAIGgJwdg&ohost=www.google.com&cid=CAASJeRo6vrphlYp1tS2wANeZ1SoTcYvA8ttOiJe6-QQhc-bi3bjodM&sig=AOD64_1egRNycMhUTFEuzQpWbY-jxIQTog&ctype=5&q=&ved=2ahUKEwi_6fOIlv_-AhXfATQIHYVCAiYQwg8oAHoECAQQDA&adurl=

Here is the cleaned up link: https://www.amazon.com/Fastronix-Au...locphy=9033266&hvtargid=pla-667529853966&th=1

 

[Guyfang]

Lets take a look see, just what has power here, when the set is in the run position. Thats when the CB pops, right?

The very first thing I would do is remove every wire from S1 and rehook them up as per the wire diagram. Then try it again.

If it still pops, then take the wire off terminal S1-3. Turn the S1 to run position, and see what happens.

If it still pops, then look at the diagram and see what is in that circuit. Its the blue color.

 

[Blockwarden]

Lets take a look see, just what has power here, when the set is in the run position. Thats when the CB pops, right?

The very first thing I would do is remove every wire from S1 and rehook them up as per the wire diagram. Then try it again.

If it still pops, then take the wire off terminal S1-3. Turn the S1 to run position, and see what happens.

If it still pops, then look at the diagram and see what is in that circuit. Its the blue color.

Your diagram was a great help. I found the issue, the fuel cutoff solenoid. After unplugging no more pop. It occurred to me that the last problem that we had was rodents building a nest on the main bus bar in the compartment behind the panel. I took off the top and checked, guess what I found. A well established nest where the bus bar again was caked with nesting materials, urine and feces. Scrubbed it all out with a stiff plastic brush and went after it with the shop-vac, then plugged the fuel solenoid back in, no more blown breaker.

Any good advice on keeping mice out of these things? I thought about covering all the ventilation ports with sheet metal by gluing the Harbor Freight neodymium magnets on the chassis, but I am guessing there are plenty of other methods of ingress.

I'll get it put back together and see where it goes.. Oh and I ruled out the Aux fuel pump, getting that cover off was a pain in the *ss.

Thanks for all the help, it led me in a more logical direction for troubleshooting that got me to the problem Just in time, the power company is having a scheduled shutdown starting at 10PM that goes through 5AM.

 

[Mullaney]

Your diagram was a great help. I found the issue, the fuel cutoff solenoid. After unplugging no more pop. It occurred to me that the last problem that we had was rodents building a nest on the main bus bar in the compartment behind the panel. I took off the top and checked, guess what I found. A well established nest where the bus bar again was caked with nesting materials, urine and feces. Scrubbed it all out with a stiff plastic brush and went after it with the shop-vac, then plugged the fuel solenoid back in, no more blown breaker.

Any good advice on keeping mice out of these things? I thought about covering all the ventilation ports with sheet metal by gluing the Harbor Freight neodymium magnets on the chassis, but I am guessing there are plenty of other methods of ingress.

I'll get it put back together and see where it goes.. Oh and I ruled out the Aux fuel pump, getting that cover off was a pain in the *ss.

Thanks for all the help, it led me in a more logical direction for troubleshooting that got me to the problem Just in time, the power company is having a scheduled shutdown starting at 10PM that goes through 5AM.

.
A lot of folks have added "Hardware Cloth" over the vent openings and on the bottom of the generator chassis. Hardware Cloth is similar to screen wire but with quarter inch holes in the mesh. Sadly, big enough to let in the bees who can eat you alive. Best part though is that type mesh will keep out the mice and/or rats. Affix the hardware cloth with washers to hold the wire and maybe a pop rivet. Other choice is glue or epoxy.

 

[Light in the Dark]

I use 1/4" hardware cloth and self tapping sheet metal screws for the large cutout under the engine. Can do the same over the side vent inlets if you want for extra coverage (mice are assholes). For the battery drain holes they are covered when the batteries are in place, but using some self sealing aluminized siding tape or similar is cheap insurance.

 

[Blockwarden]

Hardware cloth it is, I have a plethora of self tapping sheet metal screws. The bottom may be more problematic as it is bolted down on a cement slab that is under a small lean-to that I would need to disassemble the wall and unbolt the unit to lift it with the tractor forks. But, I have been given a path and will figure it out

Thanks again to all for your help and advice!!

 

[Blockwarden]

I use 1/4" hardware cloth and self tapping sheet metal screws for the large cutout under the engine. Can do the same over the side vent inlets if you want for extra coverage (mice are assholes). For the battery drain holes they are covered when the batteries are in place, but using some self sealing aluminized siding tape or similar is cheap insurance.

On aluminum tape. I actually have rolls of it that are normally used on aircraft, thick and super sticky (I used it to repair a tree limb puncture on our metal roof more than 10 years ago and it is still holding strong). Improvisation right?

 

[Light in the Dark]

Hardware cloth it is, I have a plethora of self tapping sheet metal screws. The bottom may be more problematic as it is bolted down on a cement slab that is under a small lean-to that I would need to disassemble the wall and unbolt the unit to lift it with the tractor forks. But, I have been given a path and will figure it out

Thanks again to all for your help and advice!!

The cutout under the engine is about 6" x 6"... a rodent superhighway into the machine. Especially under the conditions you have it installed.

 

[Gustavo]

hi i am new at this channel I purchased a MEP 802 generator a year ago with 130 HRS No problems until now i run this generator every other week for at least 30 min they shut power and that' when i noticed the problem , run for 2 hr a 20% and stop working i try restarted but struggle is just cranking but won't i Star the engine i turn the nob prime i don't hear the clicking noise i wait for 10min try again then i turn the knob to prime i can hear the engine getting prime in it work four 2hr then the engine dies again it sound like running out of fuel but that tank is full .i need some advice thanks

 

[Light in the Dark]

You should start your own thread on this, maybe @Guyfang can help you out with that.

Have you verifiied that your batteries are still good? It sounds like they are on the edge of failing.

 

[Light in the Dark]

You should start your own thread on this, maybe @Guyfang can help you out with that.

Have you verifiied that your batteries are still good? It sounds like they are on the edge of failing.

Which also brings to mind that your alternator may also not be working properly to recharge the cells under use. You should take the batteries somewhere they can be properly tested.

 

[Gustavo]

Which also brings to mind that your alternator may also not be working properly to recharge the cells under use. You should take the batteries somewhere they can be properly tested.

thank you very much for you advice i noticed to that needle on the battery charge is not on the green line once in while i had to charge the battery i am going to test the alternator or replace appreciate your help thank you

 

[Light in the Dark]

Let us know the outcome

 

[Guyfang]

Gustavo, Please write your state in the location block. Its a forum requirement.

 

[Gustavo]

Gustavo, Please write your state in the location block. Its a forum requirement.

Gustavo, Please write your state in the location block. Its a forum requirement.

hi I am locate in southern California (San Diego ) Thanks for the help on the generator problem I hope i can help somebody out there just like you help me by