803a won't restart

[Daybreak]

Both fuel filters were changed when I took possession of the generator.

Howdy,
What does this mean?

Someone said they changed them?
It seems you have a answer why it doesn't run right too.

Not running smooth. Fuel issue. Have a good baseline. saying you checked them means nothing here.

Disconnect the primary and take a sample reading of fuel flow amount . (procedure is in the TM)

When priming, you can hear the sounds of the airtex pump. When priming, you can hear the hollow sound then becomes a more solid filled sound.
You do not know what to expect from a MEP generator for priming.

 

[TheAlfredo]

It means both fuel filters were changed when I bought the generator. I was also given the original fingers that were on the machine. I don't have all the answers. But if you think I fuel filter won't pass fuel when the engine is hot and then passes fuel when it cools...I would love to hear the reasoning. I'm here to learn about the generator in particular. I do have knowledge of engine mechanics.

 

[TheAlfredo]

I did notice the Barel filter. I was going to bypass it when testing the pump.

 

[Daybreak]

Howdy,
I am not asking something which needs a lawyer.
A simple answer helps here.

You changed all fuel filters? and primed it properly?

 

[TheAlfredo]

Yes all filters have been changed with the exception of the barel filter next to the pump. I've been looking up that part number but can't seem to find anyone that sells it. I like to keep spare filters on hand in case I'm in a bind.

And yes it was primed properly. Runs 100% perfect for the first 15-30min until it gets warmed up and then it starts fluctuating the RPM If I turn it off, I have to wait 30 min to cool down to restart. St this point it will restart but still run irractily. I have to let it cool for an extended period of time for it to run perfectly again.

 

[TheAlfredo]

I do have two short videos of the gen running...one when it is cold start and perfect...and the other when you can see the Hz/rpm rise and fall when hot. But I don't think videos can post here.

 

[jamawieb]

Instead of swapping the fuel pumps, you may want to do a flow test when its cold and then when its hot. Just unhook the hard line going from the pump and slide a rubber hose over that end and put the other in a gas jar. Then turn the pump on for 1 minute and see if its putting out the same amount of fluid when cold and warm

 

[Light in the Dark]

I find empty plastic milk jugs (or water jugs of the same construction, but semi-transparent) work well here too.

 

[Zed254]

Daybreak gave you the Airtex G-17 barrel filter info. Here's a couple https://www.summitracing.com/parts/ATX-G17, https://www.carid.com/airtex/electric-fuel-pump-mpn-g-17.html

 

[TheAlfredo]

I haven't found any info on flow rate for the pump...only PSI. Not that they are mutually exclusive. But thank you. I'll try this first before pulling off the Aux pump.

 

[Zed254]

I could not find the Airtex E1074 when I was looking for spare pumps. I ended up buying the Airtex E8131 (primary) and E8267 (Aux) as spares. I've only used the E8267 as a transfer pump so do not know if they will be a perfect replacement when one of my generator pumps fail. I've attached an Airtex Fuel Pump sheet that provides the info I used to make my selections. It contains flow data for these pumps. Unfortunately the E1074 is not listed.

 

[TheAlfredo]

I just look at the TM and the Fuel tranfer pump should have a flow rate of at least 25oz min...aux pump at least 32oz per min. Last night a read the PSI requirements...but cant seem to locate them.

 

[Suprman]

Maybe one of the hoses somewhere is sucking air and only does it when hot the hose material expands.

 

[Guyfang]

You can swap the aux and main fuel pump. BUT, you may have to bend some lines to get it to fit. This would for me, be the last step.

You can bypass the barrel filter, and see if this affects the pump and the engine operation. Measuring your pump output cold and warm is a good idea. You could also open up the tank compartment, and disconnect the fuel supply hose, and disconnect the fuel pump input line, and apply some compressed air. You never know what you may find.

I would replace the barrel filter because I don't trust them a lot. I was told that the army bought into the barrel filter because the pumps did not do well with dirty fuel. Dont quote on that, because I can not remember if someone reputable said it or not. But if the fuel pump is getting choked for fuel, that would be a fine place to look. I have to tell you, I never remember the pumps getting real hot. Warm maybe, but no more then a little bit.

One of the reasons I asked if you have another similar set is so you might think about doing comparisons of operation, but swapping the E2. If it works well in another set, then its probably good.

 

[eatont9999]

I'm using an aux pump for my primary pump on my 803. I had to buy smaller JIC fittings to get it to work. The original (square shape) pump used 3/8" NPT to JIC fittings and the Aux pump uses 1/4" NPT to JIC fittings. I bought 3 pumps online that claimed to be 803A fuel pumps but they all were aux pumps and the ads did not mention it.

I'm not worried about flow rate, these engines will run just fine on a surprisingly low rate of fuel flow. The injection pumps are not cooled by return fuel, so nothing to worry about there.

Edit: I would not be surprised if the barrel filter is plugged up. Take it off, back flush it with brake cleaner and see what comes out. My guess is that it is filled with sand. Get what you can out and reinstall.

 

[Bmxenbrett]

I would get the unit running rough again and crack a fuel line with a bucket under it. Everything is pointing to a fuel issue. You could also run the set on a external tank. I would buy a new main pump and plumb the pressure and return both from this external source.
btw. Did you order a filter set off ebay?

 

[Guyfang]

Indeed. Everything points to a fuel problem.

You our are posting info on several different threads. It's not possible, at least for me, to keep up with the who, what how or when, of what you are doing.

I wish you you well with your efforts the fix this machine.

 

[TheAlfredo]

Thank you Guy....its getting confusing to me as well. Posted in a couple threads because as I read someone else's issues, it sounds like what might have been my issue.

But as of today...my gen decided to run perfectly. So I think posting on this issue is hopefully over.

Thanks to you and everyone else that commented.

 

[Daybreak]

Howdy,
It sounds like you jumped the gun way to fast and did not want to listen to what was needed to be done.

I specifically asked if it was properly primed after the fuel filters were changed. You could very easily had a air pocket which would not be vacated since you had it running. It was using that fuel and working, but, not filling the filters completely.

MEP generators are different. You actually leave it on prime a long time after filter changes. The fuel filters will fill, and any excess will then be returned to the tank via the fuel return lines. The same thing applies to starting sequence. You turn it to prime and run... wait... turn to start, hold it there... wait, oil pressure it up, now release it. The starter actually disengages after it starts and you are then flashing the field.

A diesel mechanic with no experience with a military diesel generator would not know these nuances.

So, it sounds like you have finally gotten all the fuel lines and filters filled with diesel. Since it has been sitting, you should also look at a additive to assist in cleaning the injectors.

The MEP-8xx units do not like to run with no load. The work best with a 70% load or higher. There is a wet stacking concern with no-load, or low load operation.

Start on this thread MEP-802/803 Filters and Parts the 2nd post has quick links to other important stuff. Farther along are links to the manuals. Farther along the thread are added updates to important stuff. (yours was reset, so it should have the fuse mod)

 

[TheAlfredo]

Thank you Howdy I still plan on emptying in the tank and replacing the 2 fuel tank well nuts. The one on the top of the tank looks dry rot...or something. Didn't see the one on the side. Its just falling apart and wouldn't want it leaking at an inopportune time.