MEP-003a Starts and once heats up dies.

[itsmerandy]

Hello, I purchased a non running MEP-003a for $500 with just over 2 hrs on the meter a year or so ago and finally had some time to work on it. So I changed the fuel out on it and then rebuilt the Ambac IP and tried to start it, took a little bit to get it running but finally fired up on a couple of cylinders for a bit before the other two started working. It puffed out a lot of white smoke and finally cleared up, I ran it for probably 10 minutes and then shut it down. The next time I tried to fire it up it took a little bit to fire off but as soon as I let off the starter switch it died. So I did some diagnostics and found that the thermal shut off switch was open, so I bypassed the thermal switch and it started, ran fine until after it started warming up, then started missing and puffing black smoke out of cyl #3-4 exhaust and then dies. So my questions are - 1.) is the thermal shut off switch a one time blow or is it supposed to reset on its own? 2.) would it be the injectors causing the black smoke and stalling of the engine?
The engine did seem really hot after the first run, once I shut it off smoke was rolling out around the cylinder heads but I figured that was all the dead leaves and debre that got in it from sitting outside for so long, but worries me since the thermal switch opened. Any help would be appreciated. Thanks.

 

[rickf]

The very first thing I would do is remove the shrouds and blow out any debris! That is your cooling and also check to make sure the louvers work freely. If those or the thermostat are frozen they will never open and it will overheat. The overheat switch will reset when it cools off.

 

[itsmerandy]

The very first thing I would do is remove the shrouds and blow out any debris! That is your cooling and also check to make sure the louvers work freely. If those or the thermostat are frozen they will never open and it will overheat. The overheat switch will reset when it cools off.

Thank you Rickf, So I do need to find a replacement Overheat switch as this one stays open even when cool. If you know of any suppliers that might carry this switch please let me know. I can open the louvers with just a little force against spring tension but haven't ran it long enough to see it will open on its own yet, I will take it apart and clean the fins out good like you suggested.
I have just been reading its best to remove the fuel tank and filter housings and clean them thoroughly, so i need to find out what replacement filters I need if anyone knows their part numbers I would appreciate it.

 

[Chainbreaker]

The Thermal Switch part # can be found in the XXXX-24 parts manual that you can then use to then Google the part. The TM listings, if you haven't found them already, are at the top of this page.

About 6 months ago I found one that was very reasonably priced from some lawn mower parts shop in Florida. If I get some time tomorrow, I will see if I can find the receipt if I still have it.

Are you are waiting until the oil pressure builds to at least 30 PSI before letting off the start switch? If not, it will die after letting go of starter switch.

Also, said you rebuilt the IP are you sure you got it reoriented correctly? Member @Ray70 did a write up in another thread about a month or so ago with a photo of cam lobe position on how to verify that the IP is installed correctly. Even if you put it back in the way it came off it could have been installed incorrectly previous to your ownership. Some of the symptoms you describe could be due to IP issues. Wrong timing button, or 180 deg out of orientation of the IP itself.

Also, your unit could be a "Reset" (rebuilt unit) though I don't see a "Reset Tag" on it. Normally the mfg's placard on the side of control box will have entries in: Date of Mfg, Warranty Date, the contracted MFG's Name & an Inspection Stamp as unit was built on contract. Regardless, your unit looks to be in pretty good shape overall & appears complete.

 

[Ray70]

Sounds to me like 2 possible problems, both of which you have already touched on.
The symptoms of hard start, quickly getting hot , smoke and shut down after warm up can be related to either the IP being 180* out ( or otherwise installed out of time ) or you could have injectors that are leaking, stuck open or otherwise not "popping" as they should.
This is assuming that the IP rebuild went ok and the plunger and plunger guide are installed correctly.
I believe checking the injector timing using the "Flowing the pump" procedure in the manual should essentially fail if your pump is 180* out or the IP plunger is not right.
Or remove the pump, check the cam lobe location I showed in the picture in the other post to get you on PC mark of #1 compression stroke, or verify Cyl #1 on compression stroke and PC mark aligned on flywheel by using valve movement , reinstall and test.
If pump is correct, the injectors would be the next thing to check.

 

[Chainbreaker]

The Thermal Switch part # can be found in the XXXX-24 parts manual that you can then use to then Google the part. The TM listings, if you haven't found them already, are at the top of this page.

About 6 months ago I found one that was very reasonably priced from some lawn mower parts shop in Florida. If I get some time tomorrow, I will see if I can find the receipt if I still have it.

Ok, so I found the "Switch-Hi Temp Cutout" that I bought late last summer but no receipt in the box. The Onan P/N on the box is: 0309-0277 and the Retail Supplier scan tag that it had sealing the box is: AR0000773919. Date of mfg on the box said 22-Jan-2021. I paid $44.37 for the part. Hope this helps.

 

[itsmerandy]

Sounds to me like 2 possible problems, both of which you have already touched on.
The symptoms of hard start, quickly getting hot , smoke and shut down after warm up can be related to either the IP being 180* out ( or otherwise installed out of time ) or you could have injectors that are leaking, stuck open or otherwise not "popping" as they should.
This is assuming that the IP rebuild went ok and the plunger and plunger guide are installed correctly.
I believe checking the injector timing using the "Flowing the pump" procedure in the manual should essentially fail if your pump is 180* out or the IP plunger is not right.
Or remove the pump, check the cam lobe location I showed in the picture in the other post to get you on PC mark of #1 compression stroke, or verify Cyl #1 on compression stroke and PC mark aligned on flywheel by using valve movement , reinstall and test.
If pump is correct, the injectors would be the next thing to check.

Thanks Ray70 I'm pretty sure that I got the IP timed correctly I hope, I took off the valve cover #1 cyl and turned the engine over till i got to the exhaust port closing and intake valve starting to open and PC centered on marker. I put an 1/8 drill bit in the screw hole of IP so it was locked in place before installing it and removing drill bit. I haven't done the flow test though because it started up and ran good until it warmed up and lost power. I am really thinking its the number 3 or 4 injector stuck open or not popping because it starts a pre ignition knock and black smoke after it warms up and wants to stall. I'm going to try and clean/ rebuild the injectors this weekend if I have time, I have a pop tester and hoping Injectors have same connection as most Bosch injectors or I will have to find an adapter.
Chainbreaker thanks for looking that thermal switch part number up for me, I found one on Ebay for around $50 and ordered it, supposed to be NOS and hopefully will work for me. I haven't looked up the fuel filters yet for this generator but hoping they will cross over to some Wix filters I can get at Oreilly's. The one nice thing about living in Springfield, Mo. is Oreilly's main distribution center is here and can find about any part within a day.

 

[itsmerandy]

Also, I have looked all over this generator for a manufacture date but they left those fields empty on the plate you see in the pictures, It has March 2007 painted on it but didn't think they made these past 2000. Is there a way to look it up by serial number or something?

 

[Chainbreaker]

Also, I have looked all over this generator for a manufacture date but they left those fields empty on the plate you see in the pictures, It has March 2007 painted on it but didn't think they made these past 2000. Is there a way to look it up by serial number or something?

That 2007 date is the date of the CARC paint. The last date of mfg for the MEP-002a & -003a was 1992 & not that many 1992's that I've seen. 1990's & 1991's were considered late models in the production run that started, I think, in the early 1980's. My oldest MEP-002a is a 1986 & my newest is a 1991.

 

[itsmerandy]

That 2007 date is the date of the CARC paint. The last date of mfg for the MEP-002a & -003a was 1992 & not that many 1992's that I've seen. 1990's & 1991's were considered late models in the production run that started, I think, in the early 1980's. My oldest MEP-002a is a 1986 & my newest is a 1991.

Wow, I didn't realize they were that old of a model, I really thought this unit was less then 20 year's old, everything that I have taken apart looks newer on the inside like the insides of the panel's (no dirt or dust) immaculate. It must have set inside a warehouse for most of its life, it looked new when I got it, now its looking older since it's sat outside for over a year and diesel line is leaking.

 

[glcaines]

Fuel filter element --- Fram C1125PL
Fuel Strainer element --- Fram 35070
Oil Filter element --- Fram CH6PL
Air Filter --- Donaldson --- P10 1222

 

[itsmerandy]

Fuel filter element --- Fram C1125PL
Fuel Strainer element --- Fram 35070
Oil Filter element --- Fram CH6PL
Air Filter --- Donaldson --- P10 1222

Thank you so very much, I have been needing those. How do you like your M1030M1? My cousin use to have KLR650's and we would go riding all the time, diesel powered would be a unique experience.

 

[glcaines]

Thank you so very much, I have been needing those. How do you like your M1030M1? My cousin use to have KLR650's and we would go riding all the time, diesel powered would be a unique experience.

I love my M1030M1. The only thing I don't like about it is that it sits very high, and although I'm 5'8" my feet barely touch the ground. Otherwise, I really like it. It really handles well and has a lot of torque. I've only had a few problems since I got the bike 4 years ago. I had a rubber fuel like start leaking, which was a very easy fix. I also replaced the battery once. Then, about a week ago, I had a front tire go flat. I replaced both the tube and tire.

 

[Ray70]

Your description of how you installed the IP does not sound correct!
Rotate the motor clockwise. Watch the exhaust close, Intake open, then intake CLOSE, then continue rotating 3/4 of the way through the compression stroke until PC comes up to the timing pointer.
It sounds to me like you stopped during the intake stroke.
The intake needs to close then you need to rotate probably 90* more past that to get almost to TDC after compression.

 

[Ray70]

Try removing the valve cover again, rotate it again beyond the intake valve closing, continue rotating through the compression stroke until "PC" is at the pointer, then check the IP alignment hole with drill bit again to see if it's aligned with the slot at that point.
If not, pull the pump off and reinstall it correctly.

 

[Ray70]

On the filters, the Fram filters fit perfectly. They do cross to WIX 33113, but with minor fitment issues.
The Wix 33113 fuel filters have a different opening in the center which requires you to either remove the 3 finger alignment tab on the center tube in the filter canister, or bend the center ring on the filter accordingly to let the canister's alignment tab fit through.
On the oil filter, Fram comes with the correct gasket. The Wix 51004 filter does not have the right size gasket in the box.

 

[rickf]

I have to agree that the timing is wrong. What you described is the valves overlapping which is 180 degrees out from TDC compression.

 

[itsmerandy]

Your description of how you installed the IP does not sound correct!
Rotate the motor clockwise. Watch the exhaust close, Intake open, then intake CLOSE, then continue rotating 3/4 of the way through the compression stroke until PC comes up to the timing pointer.
It sounds to me like you stopped during the intake stroke.
The intake needs to close then you need to rotate probably 90* more past that to get almost to TDC after compression.

Not disagreeing with you but if I was 180 degrees off why would it start and run normally? I wouldn't think it would even try to fire up if it was 180 degrees out of time would it? Could I have assembled the IP wrong somehow that would cause it to be 180 degrees off and that's why it's running and If so will that hurt it to run that way?

 

[Ray70]

I've seen it a dozen times. When installed 180* off it will still run ( but may be hard starting ) for a short period of time because although the fuel is injecting at the wrong time, there is still fuel in the cylinder that will ignite on the next compression stroke.
The issue is that because the fuel timing is way off and virtually unregulated, the motor will quickly heat up.
I bet if you ran it again you will find that the valve covers get extremely hot within less than 5 minutes.
Believe me, if your description of how you installed the pump is accurate, you are indeed in the wrong position. You need to rotate past the intake valve closing and almost all the way through the compression stroke.
Fuel begins to get pressurized at the PC point which is just a little before #1 TDC of compression.
Sounds like you installed the pump around the beginning of the intake stroke.

 

[Chainbreaker]

In sections of this thread Ray discusses the how-to's of IP timing. In particular, on pg 10 Post # 183 has the picture of the proper cam lobe position.