My first green machine

[The_New_Guy]

Well, I've done it now. I picked up my first winning auction - a MEP016D with the Yanmar L70 and about 80 hours on it. Got it home, looked it over (wondered why I seem like this stuff so much) and quickly noticed someone didn't think the oil filler cap really needed to be screwed back on. So, I flushed the oil tank out a few times getting a strange mix of sand, mud, and grey fluid. Next I tightened down all the lines, filled it up with good fluids, and pulled the cord. It started up and ran great. Multimeter testing indicates the gauges aren't 100 percent but it runs great and makes solid power.
HOWEVER, I have a couple questions regarding the fuel pump and set tank. Namely, how the **** do I get the pump to work? There are two wires coming out of the motor and into a black box with one hot coming back out. When I test the line (with a good multimeter) I get ~11V AC and ~57V DC - which current is it supposed to be and is this correct?
So, there seems to be power but the pump won't fill from the belly (set) tank. My tank selector switch also happens to be broken so I am looking for some guidance on how it should be pointing to pick up from the lower tank.
Any help is appreciated! Thanks!
BTW - everything I have read here in the past is pretty awesome and I apologize if this has been covered previously - I just couldn't find it.

 

[coyote62ny]

take your fuel selector valve apart its just the handle thats broke from what i can see in your pics clean the valve good inside and put some oil on the internal parts just to make it turn easyer . the fuel pump is electric you would most likly have to have batteries on the set it might be a 12 volt but most likly 24 volt start this pump may be just an auxallery fuel pump to keep the tank on the engine full

 

[ElCapitan Dave]

Congratulations on a good looking MEP-016D. As an owner of two of these MEP-016Ds I have had similar problems. The military never updated the Tech manuals for this set to include the Yanmar diesel conversion. All the documentation was provided within the conversion Kit which was a single Stock number and often issued to the units that owned the MEP-016A/C generators. So I have had to resort to making my own documentation. Based on trouble shooting both of my generators I have found out the following information.
You should have a panel bolted to the frame below the manual recoil starter. This panel has a starter toggle switch and a single pole NATO plug for providing 28V DC to the generator. I first thought this provided power to the starter and fuel pump. It does not. It only provides power to the starter.
The 24V Facet fuel pump is connected to the internal 24V Alternator (behind the recoil starter) through the black rectifier (four wires) and in series with the magnetic float switch which is in the bottom left side of the Yanmar Fuel Tank. The float switch automatically turns on the pump when the Yanmar fuel tank gets low and off when it is filled from either the generator tank or the external fuel tap.
In my case, neither of my generators has a good float switch. I still have not done all the testing yet, so there may be other bad components. However, I did get similar DC readings from the black rectifier that you got. 38VDC and 47VDC for the two sets.
Hope this helps. I will be following this post to see what you and others have to add.

 

[The_New_Guy]

Thanks for the input thus far. Coyote, the pump is an auxiliary pump to keep the top tank full when running. ElCapitan, did your fuel pumps run properly with those voltage readings? I will try to test out just rotating the fuel source selector to see if it starts to pick up diesel from the bottom tank. My float switch seems to work properly as power is coming back out of the switch in the upper tank. We'll see. It seems odd that 38-57V would be running to a 24V fuel pump. I'll keep folks posted if I try it out tomorrow. Thanks so far!

 

[Keith_J]

Voltages from the engine-mounted alternator is far from stable, most hand-held voltmeters will sample the highest peaks which is why they read high. This also plays havoc with the float switch, the 002/003 series use the same fuel pump and have a magnetic float switch for the same purpose, only it controls a valve which allows flow from the transfer pump. This prevents damage to the float switch in the 002/003 series.

The diesel conversion on the 016 was a stopgap measure at best for the single fuel battlefield doctrine.

There are measures which can prevent damage to the switch but without a battery to smooth out the voltage from the alternator on the engine, these won't work too well.

 

[The_New_Guy]

There are measures which can prevent damage to the switch but without a battery to smooth out the voltage from the alternator on the engine, these won't work too well.

Could you make a recommendation of how that might work with a battery (or two in series). I am certainly not opposed to going electric start or slipping a battery to help the fuel pump work properly - longer run times would be really nice when it's 10 degrees outside.
Thanks.

 

[derf]

There should be a regulator in addition to the rectifier. It should put out decent 28V DC or so. Do they not have regulators? Mine is in the shed and covered so I can't look at it easily.

It may have been a stop-gap solution but I like the Yanmar with the pull start option.

 

[derf]

See pic for battery wiring. Adding a regulator, if you don't already have one, would be desired for battery charging, too.

 

[Keith_J]

Since the 28 volt system is an add-on, it isn't properly engineered. Excess voltage+current is dissipated as heat which fries the regulator.

The easiest method? Skip the wonky float switch and plumb in an overflow line back to the belly tank. Install an adjustable needle valve in the pump output to restrict flow to about 4 ounces per minute. An inline filter before the needle valve will also add reliability.

The pumps are rock solid durable even with voltages over 28 VDC.

 

[derf]

BTW, a Harbor Freight dolly is well suited to the 016D.