Mep-803a water pump and stuck all the way to left fuel gauge

[The_DJ_Remixer]

Great! I'm making progress.

 

[The_DJ_Remixer]

This valve on the front of the mid block... I would think this is the coolant drain. If nothing comes out of it when I was flushing, chances are its clogged up eh? I'm considering removing it and cleanin it all up.

 

[Light in the Dark]

Well you don't know if it didn't drain if you kept the (non see through) hoses in place while opening. If you did remove the hoses though, and nothing came out... yeah wouldn't hurt to flush it. At that point though, I would remove and clean it and flush the manifold and water jacket of the block if you are dealing with enough FOD to block the drain. I would use a hose, then reassemble and flush with distilled water, then refill coolant.

 

[The_DJ_Remixer]

Yeah, I removed the hose before I opened the valve, and nothing came out. Heading back to wrench so I'll get er cleaned up, thanks again for your time!

 

[The_DJ_Remixer]

Well, the coolant drain valve and reducer were plugged and packed with crud. Got that cleaned up, did a lil painting, nothing fancy. Got the backing plate for the water pump cleaned up, I'll hit it with some etching primer and forest green paint and let it sit for a day. Got the collar apart from the plate and cleaned that up. O rings fit nice. Thanks again for all of your help everyone!

 

[Light in the Dark]

You need to really inspect the radiator, if that much garbage was in the system. How do the hoses look? They have wire reinforcements on the inside... those might be in terrible shape.

 

[The_DJ_Remixer]

Radiator is in good shape. The rad cap is loose, pretty sure there's something wrong with the cap, but I'll address that once I get this pump back together. The hoses do have the metal inside, they were full of goop, but cleaned up nicely. I just ran into another problem. This water pump 751-41022 threads do not match the oem sensors. I think I read up where a gent retapped the threads to make the oem sensors work, but I'd much rather replace the sensors with the right ones for this water pump. Pretty sure oem is SAE, and this pump might be metric. I only have threaders up to m12, the m10 x1.0 seems to be the smaller single wire sensor thread on the new pump, but I didn't go further than hand tight. What exactly are the sensors? Temp and high temp shut down? Buddy of mine swears by Cascade liquid to do a flush, with the thermostat out, with great results. I'll further clean the cooling system up once I get more time to wrench, and everything is sealed and back together. Today is my Sunday, so no work on the 803a for some days.

 

[Triton]

I had my fuel gauge stuck on empty as well, I removed the gauge and check the connections those were good, I loosened the nuts on the gauge and tapped it in my hand and came unstuck off empty. I replaced the fuel sender with a Wema 8.5" and that length is just right, i believe if it was any longer the unit would shut down from a no fuel fault light. Just a not my gauge is a Beede unit

 

[The_DJ_Remixer]

I had my fuel gauge stuck on empty as well, I removed the gauge and check the connections those were good, I loosened the nuts on the gauge and tapped it in my hand and came unstuck off empty. I replaced the fuel sender with a Wema 8.5" and that length is just right, i believe if it was any longer the unit would shut down from a no fuel fault light. Just a not my gauge is a Beede unit

I've got the same sending unit here arrived in the mail earlier today. I'll be working on the fuel system once I get the cooling system buttoned back up. Thanks for the info, I appreciate it!

 

[The_DJ_Remixer]

Looking through the TMs, it does not show the info for the sensors (1, 1 prong thin sensor | 1, 2 prong thicker sensor). I bought an onan water pump 751-41022, and neither of the OEM sensors thread into the new water pump. I found a post on here some weeks back, but I can't seem to find it now where a gent tapped the new pump threads to match oem. Can anyone tell me what both sensors are? Obviously I would think the 2 wire thicker one is for the temp gauge, but unsure of the other one. I may have to buy new sensors to match this water pump, and I need to get a lead on where to start looking. edit: If nothing else can you link me to the gent who tapped the threads out so I know 100% what the threads are. Thank you!

 

[2Pbfeet]

Looking through the TMs, it does not show the info for the sensors (1, 1 prong thin sensor | 1, 2 prong thicker sensor). I bought an onan water pump 751-41022, and neither of the OEM sensors thread into the new water pump. I found a post on here some weeks back, but I can't seem to find it now where a gent tapped the new pump threads to match oem. Can anyone tell me what both sensors are? Obviously I would think the 2 wire thicker one is for the temp gauge, but unsure of the other one. I may have to buy new sensors to match this water pump, and I need to get a lead on where to start looking. edit: If nothing else can you link me to the gent who tapped the threads out so I know 100% what the threads are. Thank you!

I'm afraid that Lister has quite the reputation for using a variety of parts. So Lister "OEM" might mean a number of different things. In general, I'm not a fan of re-threading things to different threads, but that's me. I would do a lot to avoid it. The good news about Lister, is that the pump you have is probably a cross reference to something common, and the right sensors are probably available. Someone here would probably be happy to buy some spare sensors for themselves...

Does your pump model number cross reference to the thread sizes? Have you checked both the sensor threads and the pump threads? Do you have a micrometer and thread gauges that fit? If not, or in addition, can you try a few bolts/fittings from around your shop to determine the threads?

All the best,

2Pbfeet

 

[Guyfang]

Is the part number on your water pump the same as in the ARMY TM? No. It isn't. You have bought the wrong pump. Therefor the threads might not be the same. The part number you used has a compleatly different NSN. I looked both NSN's up, and they are not interchangeable.

You wrote:
Looking through the TMs, it does not show the info for the sensors (1, 1 prong thin sensor | 1, 2 prong thicker sensor). (What info?) I bought an onan water pump 751-41022, and neither of the OEM sensors thread into the new water pump. I found a post on here some weeks back, but I can't seem to find it now where a gent tapped the new pump threads to match oem. Can anyone tell me what both sensors are? (Maybe you need to look in the TM?) Obviously I would think the 2 wire thicker one is for the temp gauge, but unsure of the other one. I may have to buy new sensors to match this water pump, and I need to get a lead on where to start looking. edit: If nothing else can you link me to the gent who tapped the threads out so I know 100% what the threads are.

Perhaps looking at the TM's first, could save you money. And slowing down a bit to check and double check will save you money.

 

[The_DJ_Remixer]

Is the part number on your water pump the same as in the ARMY TM? No. It isn't. You have bought the wrong pump. Therefor the threads might not be the same. The part number you used has a compleatly different NSN. I looked both NSN's up, and they are not interchangeable.

You wrote:
Looking through the TMs, it does not show the info for the sensors (1, 1 prong thin sensor | 1, 2 prong thicker sensor). (What info?) I bought an onan water pump 751-41022, and neither of the OEM sensors thread into the new water pump. I found a post on here some weeks back, but I can't seem to find it now where a gent tapped the new pump threads to match oem. Can anyone tell me what both sensors are? (Maybe you need to look in the TM?) Obviously I would think the 2 wire thicker one is for the temp gauge, but unsure of the other one. I may have to buy new sensors to match this water pump, and I need to get a lead on where to start looking. edit: If nothing else can you link me to the gent who tapped the threads out so I know 100% what the threads are.

Perhaps looking at the TM's first, could save you money. And slowing down a bit to check and double check will save you money.

The photo of the pump assembly doesn't show either of the sensors listed. I took a logical guess that ones for the gauge and the other is for a high temp shut off. I'll dig some more into the other tms and see what I can come up with. Green like the money I work hard for, I don't drink, do drugs or date loose women. I can respect some criticism since I'm askin alot and a newb, I get it...but sir, don't worry about what I spend my money on, I'll buy 10 45$ water pumps if I have to. I live debt free and simply want to get this generator up and fully operational before shit hits the fan with all the crazy people. Peace be with you.

 

[The_DJ_Remixer]

I'm afraid that Lister has quite the reputation for using a variety of parts. So Lister "OEM" might mean a number of different things. In general, I'm not a fan of re-threading things to different threads, but that's me. I would do a lot to avoid it. The good news about Lister, is that the pump you have is probably a cross reference to something common, and the right sensors are probably available. Someone here would probably be happy to buy some spare sensors for themselves...

Does your pump model number cross reference to the thread sizes? Have you checked both the sensor threads and the pump threads? Do you have a micrometer and thread gauges that fit? If not, or in addition, can you try a few bolts/fittings from around your shop to determine the threads?

All the best,

2Pbfeet

Yes sir I have a micrometer, I'll get it sorted in the next few days... I remembered a post I came across that had the info readily available regarding thread info and was hoping someone remembered that post and would link me to it. The search on here is fairly decent, but I'm having a bit of difficulty finding that post/thread again. I blame it on not reading the tms 100%. Imagine a world where the experts swallowed their pride or their 10th beer and actually helped other good hard working people with their questions instead of "you didnt read all 10,000 pages of the TM, you dummy!" I had to deal with that when I was building my m1009 as well. Not everyone is the upmost expert at Onan Cummins diesel motors. but I'm learnin more and more each day! Gotta learn somehow, even if I bought the "wrong" pump. I will say this: I will get this pump to work, one way or the other.

The smaller sensor thread on the new pump is m10x1.0 I'm pretty sure.. the bigger one Im not so sure of yet as I dont have a thread checker that big in my kit and no random bolts of that size layin around. (forgot about the micrometer haha)

I also think its a great idea to have certain parts and such layin on the shelf for backup (moreso with these generators when SHTF) Thanks for the help it's appreciated.

 

[Guyfang]

You still don't get what I mean. Its not about money. Slow down a bit before buying things. Its just better to take a bit more time to get it right. Sorry your offend. I in turn mean no disrespect.

 

[The_DJ_Remixer]

You still don't get what I mean. Its not about money. Slow down a bit before buying things. Its just better to take a bit more time to get it right. Sorry your offend. I in turn mean no disrespect.

I also mean no disrespect.. I work 3 jobs so time is always against me. I'll get this sorted this week hopefully.

 

[The_DJ_Remixer]

So the next person searching for a water pump for the 803a doesn't waste their time and get caught up in a situation like mine: Although the listing says this " Water Pump 186-6178 for Onan US Military Generator MEP-802A MEP-803A 186-6714" https://www.ebay.com/itm/387255206365 this is not 100% compatible. The sensor holes are not the same thread.

 

[The_DJ_Remixer]

I'm afraid that Lister has quite the reputation for using a variety of parts. So Lister "OEM" might mean a number of different things. In general, I'm not a fan of re-threading things to different threads, but that's me. I would do a lot to avoid it. The good news about Lister, is that the pump you have is probably a cross reference to something common, and the right sensors are probably available. Someone here would probably be happy to buy some spare sensors for themselves...

Does your pump model number cross reference to the thread sizes? Have you checked both the sensor threads and the pump threads? Do you have a micrometer and thread gauges that fit? If not, or in addition, can you try a few bolts/fittings from around your shop to determine the threads?

All the best,

2Pbfeet

Hey bud, do you perhaps have any links to the sensors or pump threads you mentioned? Im not coming up with anything using the search on this site. Thank you!

 

[The_DJ_Remixer]

So after messing with this fleabay pump this morning there are 2 things. 1. It does actually fit and will work. The casting is a C- grading. Lots of casting flakes that will need cleaned up in fear of them breaking off and getting stuck in the radiator etc. 2. The threads for the temp sensor and temp switch are very poorly tapped. The 2 plug threads, ironically, were fine. The reverse thread for the fan is also fine. I may call this divine intervention, because my Thermostatic Switch 8037122 was cracked on the one side and would have eventually failed, imo. I forget what the temp sensor thread tap was (from another set at my garage), but I do know that the temp switch thread was 3/8 18 npt.

 

[Light in the Dark]

There is a reason why Lister Petter has gone bankrupt so many times (and is now nothing more than a brand name for a Chinese engine manufacturer).