New MMI Flexible Impeller Pump

[Don Moyer]

MMI's new flexible impeller pump is interchangeable with the early gear type pumps, as well as any of the later OEM flexible impeller pumps used by Universal.

The shaft is retained between two packless ball bearings, which eliminates the need for the small snap ring on the outside of the impeller to prevent the shaft from floating. The grease cup has also been eliminated by the packless bearings.

The pump includes an MMI Quick-Change back plate to facilitate on-boat replacement of the impeller. The Quick-Change back plate is designed with an o-ring and 4 captive thumb screws. The captive feature of the thumb screws prevents them from being dropped into the bilge when removing or replacing the cover.

This pump has been designed to use the same shaft lip seal as Jabsco and Oberdorfer models, and the impeller is the same as those used in the Oberdorfer 202 and 201 series pumps.

[Jim McDonnell]

MMI Pump

Now that I have the beautiful new Pump it is time to install it !

HELP

1. Do I take the impeller and shaft out before installing to make it easier to fit the shaft groove into the accessary drive ?

2. Do I put any sealant on the water fittings that I have to install on the pump (taken from the old unit). If so - what?

3. Do I put sealant on the bolts securing the pump to the drive - if so what?

4. Does the brass washer go beside the head of the extender bolt.?

5. Any other helpful tips.

Jim.

[Don Moyer]

Jim,

Here are the answers to your questions:

1. Do I take the impeller and shaft out before installing to make it easier to fit the shaft groove into the accessory drive?

Definitely not!

2. Do I put any sealant on the water fittings that I have to install on the pump (taken from the old unit)? If so - what?

You can use any tread sealant that you're accustomed to using on any other tapered pipe thread. If this is your first experience with tapered pipe threads, I'd recommend the old Permatex Aviation brand sealer, or even one of the newer silicone Permatex products. The selection of sealant really isn't critical. You can use most any household pipe dope that you may have lying around.

3. Do I put sealant on the bolts securing the pump to the drive - if so what?

It's a good idea to use the same sealant that you select for the tapered pipe threads since the threads of the mounting bolts are somewhat subject to letting engine oil seep out from the crankcase.

4. Does the brass washer go beside the head of the extender bolt?

Yes.

5. Any other helpful tips.

Not at this time.

Regards,

Don Moyer

[Jim McDonnell]

MMI Pump

It is done!!!. Installation completed today - much easier than I expected thanks to Don's help and encouragement.

Next stage - see it work when we go in the water in May.

Thanks again Don.

Jim.

[Don Moyer]

Jim,

You're more than welcome. Hope you enjoy the new pump for many years to come.

Don

[mike]

Cooling Pumps

Ihave Universal M25 with Oberdorfer water pump #301357.
Will a CSOB 00 365 work ?
mike.

[Don Moyer]

Mike,

Our CSOB_00_365 pump will only replace the Oberdorfer 202M series pump. According to my parts catalog, the Universal part number for the Oberdorfer 202M series is 295625. The part number that you have is referred to in the catalog as a "sea water pump". My best guess is that our pump will not work on your engine.

Don Moyer

[sanjuan28]

What are the maintenance requirements for the new pump? I assume that the shaft turns on the packless bearings unstead of the pump body (eliminating the need for the grease cup). Are the seals, gaskets, etc., in the CSOB_09_70 repair kit appropriate for the new pump, too? How often should these be replaced? How often might the packless bearings need replacing? There doesn't seem to be a seep hole in the bottom of the pump. If a shaft seal leaks, as I suspect the one on the water side of my currrent put is, where will the leakage end up? I'm losing coolant into my bilge and suspect that it is time to repair/replace my FWP.

[Don Moyer]

There should definitely be a drain hole in the bottom of the housing of the MMI flexible impeller pump, the same as you see in the top of the housing. That being said, if you're not seeing any drippage below the pump or coming out of the upper weep hole, I don't understand how you could be losing coolant through your pump and into the bilge.

The only items on the MMI pump that should ever need to be replaced are the impeller and a single lip seal. The impeller and lip seal are the same as those items in the Oberdorfer 202M series pumps, and we're still watching the fleet to establish a time change recommendation.

Would you please send me your phone number? I'd like to talk to you about your pump.

Don

[sanjuan28]

Sorry, I wasn't quite clear with my question. My Oberdorfer 202M7 fresh water pump has 4+ years on it (250+ engine hours) and is now leaking coolant into the bilge so it needs a rebuild or replacement. You offer a pump repair kit and instructions for the 202M. I'm interested in the equivalent "care and feeding" parts and instructions for the MMI pump. So the kit might include an impeller, snap ring, seal and flange gasket? What does the MMI pump use for a cam shoe that might also show wear? Is seal wear on the shaft likely to be less than on the 202M reducing the need to replace it?

Other than the pump my FW cooling system is working great. My overheating problems were solved by installing your "old style" thermosat on the manifold (removed the thermostat on the head and the bypass tube). The engine rapidly warms up and is rock steady at an indicated 170F with the 160F thermostat regardless of load. All of the futzing with bypass valves, etc., is a distant memory. Highly recommended. Now if I can keep the coolant in the engine unstead of dribbling into the bilge I'll be all set!

[Don Moyer]

Your question is very relevant. We are in frequent dialog with the manufacturer regarding a reasonable repair kit for the MMI flexible impeller pump.

We will soon be posting a small repair kit for the MMI pump which will include an impeller, water and oil seals, spare o-rings, a flange gasket, and the instructions for disassembly and reassembly (which we have already been packing with each new pump).

We will also post the other internal parts in our catalog as well, but to this point, we appear to be enjoying the improvements in impeller and seal life for which we were hoping for as a result of the truer running of the shaft within packless ball bearings and the "machined in" cam shoe in the impeller chamber.

Don

[sanjuan28]

A close examination of my Oberdorfer 202 pump showed a scored shaft, worn impeller, worn and possibly damaged bushing, etc. So I opted to buy your new pump. A close examination shows that it has indentations where the O-202 pump has weep holes but these are closed. What happens to coolant that leaks past the seal? It can't drain into the bilge as before. Are the bearings designed to take the water pressure? Will the bearings leak water into the crankcase?

I'd leave you my phone number, as you suggest above, but don't care to have it in a public forum. I can e-mail it privately if you wish.

[Don Moyer]

Sorry for the inconvenience, but the MMI Flexible Impeller pump should indeed have a weep hole in the top and bottom of the housing where the indentations are cast into the housing. It would appear that the assembler forgot to take his small screw driver and dig out the thin metal layer remaining at the bottom of the indentation. If you have good access to the bottom of your housing you could take an ice pick or other small sharp tool and poke a hole in the bottom of the indentation, or remove the pump and ship it back and we'll open up the weep hole.

Again, sorry for the inconvenience,

Don

[sanjuan28]

It is always disappointing to pay top dollar for a product only to find that it is not assembled properly and that quality assurance procedures were not effective to catch the escape. The pump is currently installed on my engine, replacing a very leaky Oberdorfer 202M (no, there is not access, it's in a sailboat). I have several trips planned in September and early October and will return the pump when I lay the boat up for the winter.

[sanjuan28]

Don,

Received the new pump. The new casting clears up the weep holes and overall the pump appears to be high quality. Thanks for addressing my concerns. I'm anxious to install the pump on my engine and enjoy trouble free operation.