M5DI engine over heating

[COOP]

19 minutes ago, dalt1 said:

Why change the tried and true ole Johnson B12-b Pump system? Thanks Malibu!

I suspect it had something to due with moving the water pump on top of the motor, and a bit of exclusivity for a time so dealers have to buy the impeller from them.

[oldjeep]

12 hours ago, ahopkinsVTX said:

I suppose I can be the first one to buy one of these. I wasn’t really planning on taking my current one out to confirm these are the same but would be really good for everyone to know. 
 

I might take the chance on this one. Can probably return it to amazon if it’s wrong. 
 

StayCoolPumps Impeller Kit Replaces Sherwood 15000K Jabsco 18327-0001-P https://www.amazon.com/dp/B01345I536/ref=cm_sw_r_cp_api_i_jXPGEbPDAD0HS

One of the comments on that listing would give me pause - never heard of "StayCool pumps" as an impeller brand before.  If it were me I'd go with a name brand.

 

https://www.bakesonline.com/impeller-service-kit-sherwood-15000k-neoprene-impeller.html

The Bakes listing has an interesting bunch of boats for that piece

Built for Sherwood 15000 G Series or P151 Raw Water Pumps. Commonly found on Marine Power Engines, Bayliner Challenger, Bayliner Wake Challenger Boats, and some older Supra Boats with the P151 water pump.

Edited March 31, 2020 by oldjeep

[ahopkins22LSV]

37 minutes ago, dalt1 said:

Why change the tried and true ole Johnson B12-b Pump system? Thanks Malibu!

While this is slightly annoying, the positives and improvements on this engine great outweighs this annoyance. So I’ll deal with buying a specific impeller.

[oldjeep]

One option for OEM

https://marinepumpdirect.com/two-pack-sherwood-15000k/

 

[oldjeep]

9 minutes ago, ahopkinsVTX said:

While this is slightly annoying, the positives and improvements on this engine great outweighs this annoyance. So I’ll deal with buying a specific impeller.

It is kind of weird to go back to a keyed pump - appears from the rebuilt kits available that the key in the pump is removable.  @Coop - can you verify that?  Just need to be careful that the key doesn't fall out when removing the impeller if it is indeed removable.

[COOP]

Key is NOT removeable.

[oldjeep]

1 hour ago, COOP said:

Key is NOT removeable.

Looks removable - like a normal half moon key, otherwise how do you get the snap ring, brass washer, bearing and seal off the shaft?  Probably a tight enough fit that it doesn't fall out though.

[COOP]

You may be correct, we did whack it with a screw driver and it did not pop out. We have not had one fall out, yet. 

Edited March 31, 2020 by COOP

[hethj7]

2 hours ago, ahopkinsVTX said:

While this is slightly annoying, the positives and improvements on this engine great outweighs this annoyance. So I’ll deal with buying a specific impeller.

Probably nothing more than rumor but some speculated moving it to the top of the engine needed a slightly different impeller to prime. Who knows?

[ahopkins22LSV]

17 minutes ago, hethj7 said:

Probably nothing more than rumor but some speculated moving it to the top of the engine needed a slightly different impeller to prime. Who knows?

Could be. I’m cool with it. Like I said I’m so impressed with everything else that if the trade off is a $73 impeller compared to a $50 dollar one. I’m good!

[gregtay]

Now you all have my thinking I should check the impeller in my M6 (April 2019 build) and just replace it if it is the old one :-S 

[COOP]

50 minutes ago, gregtay said:

Now you all have my thinking I should check the impeller in my M6 (April 2019 build) and just replace it if it is the old one :-S 

I would absolutely check it. If it were to fail on the water your motor will overheat.

[csleaver]

I think Malibu is recommending 50 hour impeller replacements on the current M5 / M6 maintenance schedule.

[gregtay]

49 minutes ago, csleaver said:

I think Malibu is recommending 50 hour impeller replacements on the current M5 / M6 maintenance schedule.

I will check if it was done during my 50 hour which I did as part of my winter service. thx

[G Spot]

For what it’s worth, my 2019 25 with the M6 was built in Feb. I changed the impeller in January after 125 hours. Was still in good shape but I change them annually regardless. 

I don’t recall what the markings were on the new one. It was not in a package from my dealer. 
 

 

[LR52924]

It was the impeller after 38 engine hours, it was shredded. 

[COOP]

10 minutes ago, G Spot said:

For what it’s worth, my 2019 25 with the M6 was built in Feb. I changed the impeller in January after 125 hours. Was still in good shape but I change them annually regardless. 

I don’t recall what the markings were on the new one. It was not in a package from my dealer. 
 

 

The one on the left is the old style that were having issues. They came in a Sherwood box. The new style doesnt even come in a box. If you order ten of them you get ten raw impellers in a box and zip lock bag with ten of the o-rings in it.

[BlindSquirrel]

1 hour ago, LR52924 said:

It was the impeller after 38 engine hours, it was shredded. 

That’s pretty good! My brothers m6 impeller lasted 7 hours....

[COOP]

32 minutes ago, BlindSquirrel said:

That’s pretty good! My brothers m6 impeller lasted 7 hours....

Yup, we had one that didnt even last 4hrs. 

[PThor]

I had the same overheating issue with my M5Di. The first impeller, Sherwood, shredded at just over 1 hour on the engine. The new impeller with the brass ring is working well. However, it seems the chunks of the original impeller have caused seal issues on the water pump. Water was shooting out of the weep hole and causing the engine to still overheat and burn coolant. A new water pump is going in tomorrow. Hopefully the overheating saga will end. 

[PThor]

On 8/19/2020 at 8:28 AM, PThor said:

I had the same overheating issue with my M5Di. The first impeller, Sherwood, shredded at just over 1 hour on the engine. The new impeller with the brass ring is working well. However, it seems the chunks of the original impeller have caused seal issues on the water pump. Water was shooting out of the weep hole and causing the engine to still overheat and burn coolant. A new water pump is going in tomorrow. Hopefully the overheating saga will end. 

It also turns out the coolant hose was leaking and adding to the overheating issue. I already had to fix the rear bilge line, not sure why there are so many hose issues on a brand new boat. Possibly from all of the heat? Never had any of these problems with my MasterCrafts or 23 LSV. 

[Dlyman]

I have a 2020 25LSV with 60 hours on it.  I’m on the 3rd impeller.  I’m so tired of replacing this thing that I call Malibu to find out what the heck is up with these.  I was give two answers, first when the impeller is produced in Mexico, they used nitrogen to cool the injection molded rubber as it comes out of the die which makes the rubber brittle.  Okay.  I was told I needed to work the issue with my local dealer because Malibu was completely replacing the Sherwood impeller assemblies with a Johnson unit.  So when I contacted my dealer he tells me story number 2... that the brass insert inside the Sherwood housing was not machined well enough so when the impeller spins around it chews itself apart.  I can tell you this IS true in my opinion.  I’ve looked at mine and noticed the machining issue right off the bat.  Someone in this thread provided a photo of the inside key way and you can clearly see what I’m talking about.  Malibu is drop shipping me a new Johnson assembly and I’ll be putting it on next week.  Can’t wait to have this nightmare behind me... impeller #4 with just 60 hours on the boat.  Why wasn’t this caught in testing????

[ahopkins22LSV]

27 minutes ago, Dlyman said:

I have a 2020 25LSV with 60 hours on it.  I’m on the 3rd impeller.  I’m so tired of replacing this thing that I call Malibu to find out what the heck is up with these.  I was give two answers, first when the impeller is produced in Mexico, they used nitrogen to cool the injection molded rubber as it comes out of the die which makes the rubber brittle.  Okay.  I was told I needed to work the issue with my local dealer because Malibu was completely replacing the Sherwood impeller assemblies with a Johnson unit.  So when I contacted my dealer he tells me story number 2... that the brass insert inside the Sherwood housing was not machined well enough so when the impeller spins around it chews itself apart.  I can tell you this IS true in my opinion.  I’ve looked at mine and noticed the machining issue right off the bat.  Someone in this thread provided a photo of the inside key way and you can clearly see what I’m talking about.  Malibu is drop shipping me a new Johnson assembly and I’ll be putting it on next week.  Can’t wait to have this nightmare behind me... impeller #4 with just 60 hours on the boat.  Why wasn’t this caught in testing????

Both defects are true from my understanding. It was a perfect storm (plus the supply chain issues created by covid for getting the fix in place.). And maybe supplier defects do not show their face until they are into mass production. Preproduction runs and testing does not always catch everything. If you read back through many of the threads on here most of the early early on M series engines had no problems. The few that were rolled out in 2019, did not have issues. So my experience with manufacturing is the supplier either changed something or their low volume process did not show they could not control process and part stability at higher volumes. 

[hethj7]

9 minutes ago, ahopkinsVTX said:

Both defects are true from my understanding. It was a perfect storm (plus the supply chain issues created by covid for getting the fix in place.). And maybe supplier defects do not show their face until they are into mass production. Preproduction runs and testing does not always catch everything. If you read back through many of the threads on here most of the early early on M series engines had no problems. The few that were rolled out in 2019, did not have issues. So my experience with manufacturing is the supplier either changed something or their low volume process did not show they could not control process and part stability at higher volumes. 

Eh, I have a relatively early 2019 build with M6 and have chewed up an impeller.   I think August/September build.  I am not sure how early the M6 was being used that year but it couldn’t have been much earlier. 
 

I don’t know what to believe anymore on what the root cause(s) are and the real fix (Johnson impeller in Sherwood pump, run dry impellers, new Johnson pump and impeller, etc.)

I blip my throttle to help prime now at startup and carry a spare.  It really isn’t impacting me other than I worry about losing an impeller when my wife is out without me and having her deal with it.  

[ahopkins22LSV]

29 minutes ago, hethj7 said:

Eh, I have a relatively early 2019 build with M6 and have chewed up an impeller.   I think August/September build.  I am not sure how early the M6 was being used that year but it couldn’t have been much earlier. 
 

I don’t know what to believe anymore on what the root cause(s) are and the real fix (Johnson impeller in Sherwood pump, run dry impellers, new Johnson pump and impeller, etc.)

I blip my throttle to help prime now at startup and carry a spare.  It really isn’t impacting me other than I worry about losing an impeller when my wife is out without me and having her deal with it.  

There are other people on here that have a 2019s that have gone about 150 hours with their original impeller. Sure its only a few, but there were only a few out there as well. I can tell you that Johnson pump/impeller is for sure being used on new boats. There is a Johnson impeller developed for the Sherwood pump, but supply is short. Replacement Johnson pump/impeller are available through your dealer. I contacted my earlier this week and a Johnson pump with Johnson impeller is getting put on my boat right now. Supply is going to be tight on everything right now so I suggest everyone contact their dealer to see what their options are.