Mep803a Cranks but won't turn over

[kekle]

Sorry to bother everyone but I can't seem to figure this one out.
My 803 was running fine until the priming pump went out a few months ago.
I finally got around to replacing it and now the starter engages but won't turn the engine over, either from the s switch nor the dead crank.
I don't ever know were to start.
Anyone have any ideas?

Cecil in Orlando
just waiting on Ian next week!

 

[Evvy Fesler]

Hi @kekle,

I have an MEP-804A that was difficult like this. I had to open the air bleeder ports in the fuel delivery system to get air out. Then it started. There’s an old saying though… if all you have is a hammer everything starts looking like a nail! In other words, just because we have the same symptoms doesn’t mean we have the same root cause. I found that the troubleshooting procedure in the TM was quite good. Have you downloaded your TMs from this website yet?

Evvy-

 

[kekle]

Hi @kekle,

I have an MEP-804A that was difficult like this. I had to open the air bleeder ports in the fuel delivery system to get air out. Then it started. There’s an old saying though… if all you have is a hammer everything starts looking like a nail! In other words, just because we have the same symptoms doesn’t mean we have the same root cause. I found that the troubleshooting procedure in the TM was quite good. Have you downloaded your TMs from this website yet?

Evvy-

Thanks for the reply.
I'll see if that helps

Cecil

 

[Light in the Dark]

I would start by taking your batteries out to a local auto store and have them both tested. If you dont have 24+ volts, your machine isn't going to do much of anything. They can show surface voltage, but can fail under load to almost zero amps. If you have not downloaded the TMs for this set, thats step #1. The manual ending -24 is the diagnostic manual. See screen grabs of what you really need to be zeroing in on:




When you know the WHEREs and HOWs... you will come to see that the manuals are so well laid out that working on a machine is possible for anyone.

 

[Light in the Dark]

The TMs for your machine can be found here: https://steelsoldiers.com/threads/a...-generator-and-mep-803-10kw-generator.148871/

 

[kekle]

The TMs for your machine can be found here: https://steelsoldiers.com/threads/a...-generator-and-mep-803-10kw-generator.148871/

Ok, I tested the batteries.
One tests fine. The other was @ 10.3v and dropped to 9.1v under load.
So I put it on a charger and will test it again in the morning.

Thanks For all your help
Cecil

 

[kekle]

I charged the battery all night and... it tested worse this morning.
So the question is do I buy one battery or two?
What are y'all's thoughts.

Cecil

 

[Light in the Dark]

You really should replace them both at the same time, with identical units (at the same time, not necessarily what was there before). Just a matched pair.

 

[Evvy Fesler]

I charged the battery all night and... it tested worse this morning.
So the question is do I buy one battery or two?
What are y'all's thoughts.

Cecil

Good morning, Cecil,

Every purchase decision that I make is in support of my goals. Why do you have a generator? Is it critical that it operates? Over all temperatures and environmental considerations? Your goals may be different than mine or apply differently.

Another thought might be to buy one battery now and see. That would at least remove a variable in your troubleshooting process. Once you know where it stands you can decide when to buy the second battery.

Evvy-

 

[kekle]

The batteries that are in it are size 26R. Is that the correct size?

Cecil

 

[Light in the Dark]

Optima Red Top 34/78 were the standard issue. I use 51Rs most of the time, as they will fit both 802s and 803s. Find a high quality battery that will fit in the spot and give it hell. You don't need the high cranking amps of larger batteries, due to your location. We need the high amps up here in the colder states in the winter.

 

[Guyfang]

If this is a keeper gen set for you, think about putting another battery in, and two months later, go through it all over again. If you can afford it, get two, and sleep well. Having once eaten insistent mash potatoes, in every possible variation, for 2 months, I would rather eat then buy the second one.

 

[Ray70]

FYI, on an 803 I typically use group 34's. They fit very well. Group 26 is non-standard for your machine, but whatever fits and works with the hold-downs will get the job done.

 

[Guyfang]

Batteries are probably the biggest problem the military has with its equipment. Want to get rich, sell batteries to the Army. On our HAWK site, after 1977, we were on what I would call a small hill. 510 meters above sea level. In winter, we had snow when the valleys had rain. And it got down to -25 or -30 cel. in the deep winter, no problem. AND THEN, the wind chill factor! The snow did not melt there so much. It was just blown away by the high winds. In the real bad weather, we would start all trucks every 90 min, or two hours. Even that did not keep up with the cold. So I built, with the help of one of my able thugs, a cart, with a 3 KW, DC gen set, with 4 batteries on it, so we could jump both the 2.5 and 5 Ton trucks, as well as the smaller trash haulers and gen sets. We put a draw bar on it and EVERYONE on duty at night got a chance to help pull it around through the snow. That's where I learned to hate lead/acid batteries. I had one blow up in my face, when it was frozen, and we were trying to jump start a gen set. I fell in love with Optima, Hawker and several other of the "new" generation of batteries. So my 2 cents on the whole deal is, never buy another lead/acid battery again in your life. And invest in a GOOD, SMART battery charger/maintainer. Best spent money you will ever spend in your life.

 

[zarathustra]

If one battery is bad, then it is likely that the second one will be going soon even if it is OK now.
Good luck with Ian....

 

[FarmingSmallKubota]

Not to Start a battery thread but my two cents on my personal machines not the ones i sell. Oreilly super start AGM battery economical group 34 in my area are $229 or right now SAMs club has duracell AGM 34 for $189 or agm marine $134