MEP-803A No Crank

[sigley89]

Back story. We have 2 803’s. One runs cherry the other has no crank.
We’ve been digging through the TM and running through the engine fails to crank troubleshoot. We have no power to the control panel. No lights or primer pumps running. What we have done so far:

ENGINE FAILS TO CRANK.
Step 1. Test for defective DEAD CRANK switch. (Tested for continuity in normal and crank position. We have continuity. Dead crank switch will not turn over engine with flipped to crank)

Step 2. Check for loose or corroded battery cable terminals or battery posts. (Good)

Step 3. Check that batteries are installed correctly
(Correct)

Step 5. Test for defective DC CONTROL POWER circuit breaker (fuse has continuity)

Step 6. Test for battery voltage at terminal 1 of starter solenoid. (Good voltage)

Step 7. Test for battery voltage at + terminal of starter solenoid with MASTER SWITCH in START position.
b. If battery voltage is not present, do Step 8.
( don’t remember if it was placed in start or not but no voltage)

Step 8. Test for battery voltage at input of MASTER SWITCH, refer to Electrical Schematic FO-1.
b. If battery voltage is not present, do Step 10.
(No voltage)

Step 9. Test MASTER SWITCH for output voltage in START position, refer to Electrical Schematic FO-1.
a. If battery voltage is present at MASTER SWITCH output temninal (7) and ground, do Step 13. b. If battery voltage is not present at output terminal, test MASTER SWITCH
( don’t remember if we did this or not. At this point we started comparing readings from the working genny to the no working one


Step 10. Test for defective battery charging ammeter shunt,
(Our reading is .8 ohms but so are the readings on the running genny. TM says needs to be below .5 ohms but the other genny has the same reading so we assumed it was good. Also checked for voltage and we have no power from the posts to a know good ground. The running genny shows 24v )

11. Test for defective Reverse Battery Diode (CR1),
TM says between 7-7.8 ohms for these but we couldn’t get more that 4 ohms on any of them. Running genny has same readings. **thinking my multimeter might be junk**

Step 12. Test for defective EMERGENCY STOP switch,
(No power to switch)

before we get too far is there anything simple we might have missed? Why are we not getting power to the control panel? No lights or anything.

Thanks for any help.

-Matt

 

[kloppk]

Not having any power at MT4 is the place to start. Need to find out why 24 volts isn't getting there.

There are two wires that get 24 volts power from K2-A1 and run to plug P6 pins 21 and 22.
The two wire numbers are 109F and 109L. Check that you have 24 volts at K2-A1.
If you do then...
Then follow the wires to P6 to be sure they are not broken or cut.
If that looks good then verify P6 in properly plugged into J6. If it is you may want to remove it and check for corrosion on P6 pins 21 & 22.
Clean P6 and J6 with contact cleaner while you have them apart.
Verify that there is 24 volts on P6 pins 21 & 22. If no voltage you need to trace back to K2-A1 and find out why.
If you have 24 volts on P6-21 & 22 then reconnect P6 to J6.
Now see if you have voltage at MT4.
If no voltage at MT4 then trace the wires 109J & 109K from MT4 to J6 to verify they are in tact.

This the a diagram of the path from K2-A1 to MT4.

K2-A2 -----Wire 109F-------P6-21 J6-21------Wire 109J----------MT4-4
K2-A2 -----Wire 109L-------P6-21 J6-22------Wire 109K----------MT4-4

 

[sigley89]

Thanks for the reply. I’ll check tonight after work and share my findings.

 

[sigley89]

Here is what we have. Connected one lead to A1and one lead to every post on K2. No voltage on any of them. Connected each post on K2 and A1 to a know good ground and no voltage.

 

[sigley89]

 

[sigley89]

View attachment 829963

 

[sigley89]

Found our culprit. Started at battery and worked our way forward.

 

[sigley89]

 

[sigley89]

She runs like a champion!

 

[Daybreak]

Howdy,
I believe that connection is double nutted. Look and feel around the bottom, you will probably find the nut which vibrated off.

Either way, good job tracking it down.

 

[Light in the Dark]

If one was loose... best time to do a once over on all nuts like this.

 

[sigley89]

If one was loose... best time to do a once over on all nuts like this.

I don't think that it came loose on its own. I think the person before me disconnected it and left it that way. We bought a trailer setup with 2 803's on it. One worked fine the other he said he could only get it running if he sprayed ether into it and then it would die out. I talked him down to $5K for both of them and the trailer. When I found the disconnected wire, we looked at the other generator to see where it needed to go to and then turned the main switch to prime and Aux and heard both pumps running. The location where the wire goes had a nut on it holding the other two cables onto it. He said he disconnected the batteries from both generators so they wouldn't freeze. In Alaska it gets -60 and does terrible things to batteries lol. I'm going to assume that he disconnected that wire as well for some reason and forgot about it, his loss. One generator has 320hrs and the other has 440 hrs. Rebuilt in 2019 in letterkenny.

My buddy is going to use one as an emergency back up and I will be using mine for primary power in the winter time. I'm off grid with solar and in the winter Alaska doesn't get much sun. This generator will charge my battery bank and power my house while it does so. My inverter has the ability to be manually adjusted to draw more power. I'm planning to make it pull about 4kW for a hour or two a day to maintain the batteries in the winter. In the summer I'll just exercise it on a rainy day. I plan to have a 300Gal fuel tank connected to it and a small toyo heater. Ill store the generator in a shed I'm going to build so that in the winter time the toyo will heat the shed to 55 degrees F. I think these generators have an aftermarket preheater on them and I'll have to do some reading on them to figure out how to use them properly. I'll post a picture of the preheater thing and see if anyone has any info on them.

BTW those fuel filters are a fucking bitch to change. Had to take the side panel off to get better leverage on it. Pretty much tore the filter in half.