Raw Water Impeller bad at 40 hours

[vision]

2013 G23 with 240 hours. Replaced raw water impeller at 200 hours as routine maintenance and impeller was in good shape. Boat started to over heat mildly today and tested the vacuum on the raw water input and it was low. Surely it could not be the impeller as I replaced 2 months ago. Yet sadly it was.

Want to make sure I did not do anything during installation that could cause premature impeller failure. I have never had issues before and the impeller change is quite simple. But is there an installation error that can lead to premature failure? Thanks.

[Paxdad]

I have gone through two this year, one at 50 hours use and the other at 7 hours of use. I did not experience an overheat as I caught it before it did from seeing the temp gauge rise. The one with only 7 hours on it was pulled for inspection purpose only, and found it was shredded. Photo attached. Both were OEM units from NautiqueParts. The pump showed no signs of wear or heat either. The only thing I could conclude that caused it (7 hour impeller) was that my through hull valve was partially closed from when I had changed the impeller when it shredded at 50 hours use and I had the valve closed and water flush connected. Nautiquehunter and I placed a clear section of tube on the discharge side of the pump to see if the system was sucking air and it was not. This is a fairly straight forward test.

[vision]

Thank you for the info. Seven hours, ****. I wonder if the manufacturer had a bad batch?

The clear tube is a great idea. I placed an access drain on my raw water intake tube to allow for water drainage/easy winterization. I use this also to check for the level of vacuum (simply how fast water is sucked from a container) which is what told me that the engine was not drawing water. But looking for air in a clear tube post the pump would really help look for a leak.

I wish these boats came with a simple flow meter right in the raw water line that would provide warning when flow dropped below a certain level at a given RPM.

[sstexan]

I had the same issue this year with my 236. I put maybe 5 hours on it before the impeller went bad. I believe the culprit was a loose connection on the hose that connects to the strainer. Mine is made out of schedule 40 and I was able to turn it 3 or 4 turns on each side. Once I replace my impeller which looked exactly like both above I have been running at 168-180 depending on hard I am running it.

I also learned if your boat sounds louder than normal, you have a problem, because water flowing through the exhaust quiets the boat down quite a bit.

Good Luck!

SSTEXAN

[Paxdad]

I can give Nautiquehunter all the credit for the clear tube idea Yes the idea of a bad batch of impellers did enter my mind. I am going to pull mine that replace the 7 hour failed unit in another couple of hours use to see how it looks. Needless to say I am a little fixated on my temp gauge these days based on my experience so far this year.

Essentially what you need is about 6" of clear tube from Home Depot and several PVC fittings sized for your boats existing cooling hose configuration, and 2 hose clamps. Remove the existing cooling hose from the discharge side of the pump and replace with the short section of clear hose and the pvc fitting and clamp it all together. Remove the through hull hose from the strainer or through hull fitting (depending how easy to access) and place in a 5 gallon bucket full of water with a continuous supply of water going to the bucket. Start the motor and observe the clear tubing for air bubbles in the system. You will be surprised how fast the pump sucks down the bucket (hence the need for the additional supply of water from your garden hose). If you observe bubbles in the clear tube you can then determine where the leak is. Just thinking out loud you could probably put an inline water pressure gauge on the discharge side of the impeller and monitor it for psi drop to determine if the impeller is failing.

[Paxdad]

I had the same issue this year with my 236. I put maybe 5 hours on it before the impeller went bad. I believe the culprit was a loose connection on the hose that connects to the strainer. Mine is made out of schedule 40 and I was able to turn it 3 or 4 turns on each side. Once I replace my impeller which looked exactly like both above I have been running at 168-180 depending on hard I am running it.

I also learned if your boat sounds louder than normal, you have a problem, because water flowing through the exhaust quiets the boat down quite a bit.

Good Luck!

SSTEXAN

When my 50 hour impeller went I thought it was associated with the FAE I had just installed however when I replaced the impeller and removed the FAE it did the same thing only 7 hours later (just to be clear without FAE installed)! However, as indicated above I did have the through hull valve partially closed. The through hull valve is now zip tied open. Temp is never above 158 with a 160 thermostat. Right at about 154 at idle.

[Dandy21]

When my 50 hour impeller went I thought it was associated with the FAE I had just installed however when I replaced the impeller and removed the FAE it did the same thing only 7 hours later (just to be clear without FAE installed)! However, as indicated above I did have the through hull valve partially closed. The through hull valve is now zip tied open. Temp is never above 158 with a 160 thermostat. Right at about 154 at idle.

Interesting. Our 2014 G23 arrived to us with a Zip Tie around the valve for the raw water input. In order to close it, we would have to slide the zip tie up to allow the handle to turn. This is only done on the raw water input valve and not on any of the ballast pumps. Wonder if this may be the reason for that. Amazing all the uses that Zip Ties bring to the world.

[nyryan2001]

Not sure if you guys are familiar with Globe run dry impellors.

Ive never used them... but the guys on the Malibu forum have used them for years and swear by them. They meet and exceed OEM reqs, and will not be damaged from running them dry, made from a different material that doesnt over heat from the friction. And just generally last longer.

[Nautiquehunter]

I have been working with Paxdad on his 210 I am leaning towards a bad batch of impellers both the 50 hour and 7 hour impellers came from the same place both were PCM parts . The one he has now came from the local dealer it will be interesting to see how it looks in a few more hours.

[NautiqueJeff]

I'll let NautiqueParts know about this thread. Maybe they can look into this.

[sstexan]

I bought my impeller from Nautiqueparts in April of this year as a reference date. It was toast after 5 hours or so..Now you got me thinking it was a bad batch as well...

[NautiqueJeff]

Ok, already got a response from NautiqueParts!

They did indeed have a bad batch of impellers, and they are willing to replace any failed impellers that were purchased from them during the first half of this year at no cost. Just give them a call and they'll set you up!

[vision]

Mine was from NautiqueParts as well. I already ordered and pay for my replacement part. But their acknowledgement of the bad supply really helps me feel better that I am not missing something else. Thank you NP!

[Dandy21]

ok, already got a response from nautiqueparts!

They did indeed have a bad batch of impellers, and they are willing to replace any failed impellers that were purchased from them during the first half of this year at no cost. Just give them a call and they'll set you up!

wow - that is service!!!

[mvsy]

Fantastic, I had the same issue, about 10 hours and it shredded. I will give them a call.