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My Findings on MEP016D Engine Fuel Controls

ETN550

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The info below is my opinion so please do not be offended if you do not agree, and your sets may be different. And feel free to interject any comments or corrections. I'm hoping this entry will start some discussion.

I recently have got three of these sets up and running and all were similar in nature.

There are three electrical systems on this unit that are totally separate from each other.

The generator controls are completely inside the box and have no connection with any engine mounted or frame mounted wiring.

The starting circuit is via the slave connection and only goes to the starter. The engine's alternator circuit does not back feed the slave plug to recharge whatever battery is connected to start it. May as well unplug the slave as soon as it is running.

The engines start quite well on 12VDC at the slave as long as the decomp lever is used. The starter solenoid pulls in fine and the starter motor gets good speed if the decomp lever is used.

The engine alternator coil windings put out 50+ volts to the rectifier which is not a regulator. So 50+ volts DC is sent to the fuel tank float switch.

The float switch is rated for 24VDC and the switch is actually a switch / relay combination. So the 24VDC relay coil sees unregulated 50+ VDC. I do not like this.

If the float switch decides it is time to activate the pump then the 50+VDC is passed to an unknown component in series. The component is a mystery to me. I have pics below. It is two wire, not labeled as to wire + or - and it has an adjusting screw on it and what appears to be a flat metal base (heat sink?) I put an ohm meter across it and it behaves like a capacitor in that the meter current charges it and the meter reading changes then when the leads are reversed the reading is negative and double and the meter reading changes back. (As though the meter current used in the ohm mode is charging and discharging the device. It says Texas instruments Klixon on it. I wonder if they are just trying to provide enough resistance or regulation to match the alternator coil to the fuel pump since rpm is constant and the pump is the only device on the alternator.

Anyway from this device the signal goes to some sort of device which is either a round tube or a square box and is attached to the shielded fuel pump wire.

Voltage measured at the fuel pump during operation is around 30 VDC.

In summary, I don't like raw 50+VDC going to the relay coil or across relay contacts rated for 24VDC. I wish the engine alternator could back feed the slave to charge a battery.

Now on to the fuel cap on the engine tank. The cap is vented but only with a one way check valve to let air in not air out. Why? What happens over time if the belly tank is used extensively? As the pump fills the engine tank air pressure will build up preventing fuel from entering. Also, injector leak off lines have combustion gasses in them and air and this will add to the tank. i do not understand why the cap is made this way. See pics. The underside rubber is very thin in the center and forms a flapper kind of seal on the center white plastic button. Air can go in but not out.

In order for the belly tank pump to deliver fuel to the tank the tank must be very low, about 1-1/2 inches of fuel. the upper float does not appear to be used and fuel level is maintaind at 1-1/2 inches, never higher. At this level the in tank fuel filter is mostly in air. Which means the filter will never be fully utilized.

Another "problem" is that the fuel exits the tank on the very bottom and only the small ridge in the filter makes a dam to stop water (which settles to the bottom) from reaching the injection pump. I believe this is a "gas" tank not a "diesel" tank. It would be much better if the tank had a small low point and a drain there. There is a drain but no separate low point for the water to collect.

All three of my units had issues with the glass sediment bowl, another hold over from the former gasoline application. I by passed them.

What I would like would be to retain the aux fuel feature, use regulated DC to run the float and pump, and be able to back feed the slave for charging a remote or on board battery. I might even think about an on board 12VDC battery and a change in fuel pump and float switch. A fuel tank cap with a manual vent open / close would be nice.

It would be nice to ditch the engine mounted tank but it is a nice feature to be able to run only on gravity feed if all the engine mounted electrics failed.

Anyway, thought some might be interested in this info.

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derf

Member
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LA
I think it should have a 24V regulator. The Chinese 186 series motors are copies of Yanmars and the starters are the same size and shape. The 24V starter may work at 12V but Yanmar has different part numbers for 12V and 24V so the correct 12V starter should work without having to engage the compression release.
I agree 50V is too much on 24V rated components. I will have to pull my D out and check it. I would think the unregulated output was around 36V or so, which I could probably live with on milspec components rated for 24V, but not 50V.
What you found makes sense, though, as the thing I took a pic of can't be a regulator considering its lack of heat sink.

Here is my D running:
[media]http://www.youtube.com/watch?v=6UGD4pxwVOA[/media]
 

nf6x

Feral Engineer
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Location
Riverside, CA, USA
I've seen the Klixon brand associated with circuit breakers before, if my memory is correct. A google search suggests the brand is also associated with thermal switches. From the looks of it, that Klixon part might be either a circuit breaker or thermal switch, as I've seen both with similar construction to that part. Do you have the TM for your generator? If not, I might have a PDF.
 

derf

Member
926
13
18
Location
LA
I've seen the Klixon brand associated with circuit breakers before, if my memory is correct. A google search suggests the brand is also associated with thermal switches. From the looks of it, that Klixon part might be either a circuit breaker or thermal switch, as I've seen both with similar construction to that part. Do you have the TM for your generator? If not, I might have a PDF.
Looks like an auto reset thermal breaker:
http://www.sensata.com/download/klixon-circuit-breaker-thermal-catalog.pdf

I do not have a manual for the MEP-016D. If you have one I would appreciate a copy or link. I have the MEP-016A manual and some Yanmar commercial manuals, but nothing on the D.
 

derf

Member
926
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Location
LA
I kept my D pretty much stock. On my E, though, I plan to ditch the starter, battery, and other non-essential parts. Having to buy and maintain a bunch of batteries doesn't seem like fun to me. I'd prefer the units be lighter and have less stuff on them that require maintenance and/or periodic replacement.
 

AllSeeingEye1157

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Union Beach, New Jersey
Picked up my MEP016D from GL about a week ago and beyond the need for a cleaning of the fuel system it is in pretty good shape. It is missing the transfer pump relay and the tin cover over the flywheel but that's it. Does anybody know where to get an OEM relay used in the refit kit? With a little searching under the refit kit I came up with Yanmar part NSN 5945-01-416-0374, MFG #183284-916000 OAK42 but that is as far as I have gotten..
I have a standard 24v relay that should meet the circuit needs but with all the discussion of raw 50 volt coming off the stator I'm leary of hooking it up.

I also can't find a rectifier just 2 quick connect lines coming from the stator. Any pictures of existing wire connections to the the original relay and pix of the rectifier would be much appreciated.

I've got 3 MEP-015As purring like kittens (or is it screaming like Banshees?) but this is my first 016D and I don't want to screw up what looks like a fine piece of hardware.
 

ETN550

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Knoxville, TN
Picked up my MEP016D from GL about a week ago and beyond the need for a cleaning of the fuel system it is in pretty good shape. It is missing the transfer pump relay and the tin cover over the flywheel but that's it. Does anybody know where to get an OEM relay used in the refit kit? With a little searching under the refit kit I came up with Yanmar part NSN 5945-01-416-0374, MFG #183284-916000 OAK42 but that is as far as I have gotten..
I have a standard 24v relay that should meet the circuit needs but with all the discussion of raw 50 volt coming off the stator I'm leary of hooking it up.

I also can't find a rectifier just 2 quick connect lines coming from the stator. Any pictures of existing wire connections to the the original relay and pix of the rectifier would be much appreciated.

I've got 3 MEP-015As purring like kittens (or is it screaming like Banshees?) but this is my first 016D and I don't want to screw up what looks like a fine piece of hardware.

There is no separate fuel pump relay in the standard conversion on the "D". Just so we have out models clear in our head the "D" is the converted "A" or "C" with the L70 Yanmar. The unit has rope start and electric start through the slave connection, no on board battery and it has a belly tank and an engine mounted fuel tank.

The wiring goes somethng like this. Generator end is totally separate from the engine side and the generator is only concerned with it's stuff when spun fast enough by the engine to make electricity for the user.

The engine flywheel stator produces 54VAC on two wires that come out behind the starter. These wires feed into a recitfier mounted to the engine block on the same side as the fuel pump just behind the pump. The rectifier wires are arranged in a square pattern with the stator wires at opposite corners, and one of the other wires grounded to the bolt holding the rectifier on the engine and the other wire is 54VDC out.

The 54VDC goes to the level switch on the bottom of the engine mounted fuel tank. The "Level switch" is actually a relay / switch combination.

Based on the tank level a single output hot lead goes to what appears to be some sort of regulator or dropping resistor and then to the fuel pump. That's it.

The slave connection and the electric starter are also totally separate from any other system. Neither the engine nor the generator will charge the starting battery that is connecter through the slave. Just use the slave to get it rolling then disconnect when it starts. Keep a battery on a separate plug in charger.

Useful hint: In case there is not a 24VDC battery available or Two 12s are not available the engine will crank and start fine with a healthy automotive 12VDC battery if the decompression lever is used. A 5/8 bolt fits inside the slave and a piece of steel or another bolt can be hose clamped to the Outer diameter of the slave connection to make it easy to use a set of jumper cables. Good info to know that it can be electric started with a boost from a 12VDC car and jumpers.

Here are some pics of the rectifier. The Two green and white wires are the AC from the stator on the engine flywheel. The solid green is the 54(+) VDC and the black is ground. The last pic is the bottom of the float switch relay with the paint scraped off showing the relay coil and float switch diagram. It's upside down.

Every one of the ones I have worked on have sucked air at the glass fuel strainer. either replumb and eliminate the strainer or install a new strainer gasket. Available at lawn mower shops.

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ETN550

New member
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Location
Knoxville, TN
I kept my D pretty much stock. On my E, though, I plan to ditch the starter, battery, and other non-essential parts. Having to buy and maintain a bunch of batteries doesn't seem like fun to me. I'd prefer the units be lighter and have less stuff on them that require maintenance and/or periodic replacement.
I'm keeping my electric start on my "E" but value the recoil backup. Consider that with an electric fuel pump the engine may not run long without fuel pressure before it dies. Pulling the rope may not be enough to make the pump work and give fuel pressure.

I plan on opening the air bleed on top of the filter separator to do a start without battery. This will break any vacuum and put a 1/2 cup or so of fuel inside the filter at gravity elevation for the engine to use while it is getting up to speed and can make electricity to run itself. The check valve in the fuel pump should prevent the fuel from siphoning out of the filter backwards into the tank.

VR2 is the 24VDC voltage regulator that feeds the entire panel. How will it perform without a battery? Maybe install a very small battery or a capacitor / battery eliminator such as used on motorcycles?

The preheat function will be lost too. Keep the slave or something similar so it can be jumped in the normal manner when possible.

Of course you will have to set the fuel solenoid manually.

I guess the whole control box could be tossed to save a lot of weight since only a modern retrofit generator voltage regulator is needed to get and maintain gen output. Hardwire the output and direct wire the voltmeter, hourmeter. Can the load meter (and CTs) and install the aftermarket $19.95 hz meter. (Can the Hz converter box)

I'm working on a highly sound attenuated design scabbed mostly from "E" parts, including L-100. It is going to be 3kw and Two speed, 1900rpm and 2300 rpm switchable by V belt. I'm roughing it out now. It will be belt drive and have an 1800rpm single phase 4 lead gen head. I'm going to reconfigure the existing control box and retain the redistribution switch for full load 120VAC or 120/240 VAC. My goal for this unit is very very quiet, slow speed, low power (run a single camper roof A/C) and very long run times, like all weekend or weeks of boondocking. I have most of the parts including the 1800 4pole 2 bearing Chinese head and am working on putting it together. I am also installing a remote sump oil tank that will take the L-100 up to 6quarts total useable oil capacity for 500hr oil changes. It is going to go into a sealed military fiberglass APU shipping container with special air ducting and fans for cooling and noise control. More on all this later. This will take a long time to do with lots of welded fabrication, plumbing, wiring, controls, testing.

If it works I may make another unit that will range from 3kw 1900rpm to 5kw 3600 rpm in 3 steps or make a variable speed / variable amp output 28VDC system feeding dual inverters (for redundancy). That is probably my ultimate goal. Would be nice to have an electronic speed control based on storage battery voltage and demand with auto stop - start determined by high - low battery condition. This would be super efficient across a wide range of loads and conditions.
 
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AllSeeingEye1157

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ETN550,

Excellent pictures!

Thanks for setting me straight about the rectifier and it looks like that's what I'm missing. if anyone knows where to get one and the part number I would be greatful.

It would be a boon to everyone working on these 016D's if someone could find the refit kit contents and the manual that goes with it. Somebody out there had to do the work when the contract went through and they must of had some sort of documentation to go by.
 

truck1

Member
332
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Location
San Anselmo,CA.
Well thought I'd revive this thread. I've been going over my new GL MEP-016d. Glad I found this thread because the wiring I thought was correct was not. Someone had the fuel pump feed hooked direct to the starter solenoid,and the upper tank float switch was also incorrect. Both wires were connected to the regulator or resistor . Not sure what it is. Also the switch leg from the slave start switch to the starter solenoid was missing also. The belly tank leaked at the drain plug (cracked). Repaired that with epoxy-no more leak. Re-routed the fuel pump circuit correctly. Also I get 39VDC out of the rectifier-not 54. So I guess reduced voltage to the float is better. Need to remove fuel from top tank to see if float and pump are working properly. Unit starts on 1 pull and runs great. Load tested and voltage is correct in all phases.Had sticky phase selector switch-fixed that problem. AC volt meter fluctuates a lot and has condensation inside. Trying to find a replacement on Ebay. Tested voltage @ lugs behind switch with multimeter and reads correct. Put casters on skid. I really like this unit. Thanks ETN550 for taking the time to post all this valuable info.
 

derf

Member
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LA
"Regulator or resistor" might be RFI suppressor. If so, it's just a noise filter cap, and not necessary.
 
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