PCM EX 343 Impeller shredding??

[Paxdad]

Guys,
I have a PCM EX 343 and am on my second impeller this season. The first one lasted approx 50 hours and the one in the photo below only 7 hours. Could certainly use some thoughts/ help on whats causing the issue. When the first one came apart I found most of the pieces in the pump on the suction side just underneath the small insert. I will have to now track down the pieces from the 7 hour impeller. Yes I am running a strainer.
Thanks.
impeller.jpgwater pump.jpg

[JLG]

Are you using lube that is included with the impellor and using a good brand not just the cheapest model you can find? Are you inserting it the correct way, as I can get a couple years out of mine but change yearly to prevent this from happening? Also do you let the boats raw water inlet fill with water before starting the engine? I noticed on an older boat of mine that my wife would start a little before the boat had chance to fill with water while putting boat in and the belt would seize and would ruin impellors quickly also. It took me a few time of this happening before I had her set fully submersed in water for a few seconds then start and I would back her in deep enough to release boat off trailer. Just my thoughts and maybe something to try. I'm sure others will chime in

[chpthril]

Starvation would be my first suspect. Maybe something large that didnt end up in the strainer, but caught in the plumbing pre-strainer?

[WakerideN]

Starvation would be my first suspect. Maybe something large that didnt end up in the strainer, but caught in the plumbing pre-strainer?

x2 on chpthril's I would suspect not getting the right volume of water to correctly lubricate the impeller.

[Paxdad]

Thanks for the replies. From what I know the impeller can go into the pump either direction. I use hair conditioner for lubing the impeller. The impeller is an OEM PCM part. The impeller stays wet so it is not starving and I always allow the boat to idle on the trailer for a few minutes prior to releasing from the winch. I am starting to think that there may be an air leak somewhere in the system which when idle is causing a lack of adequate circulation however when under load the water passing over the through hull is creating the adequate flow. Boat is not overheating.

[chpthril]

Run it on a fake a lake at idle and see what kind of flow you get out of the exhaust.

[Stingreye]

How are you putting the gasket on the housing? Assuming you have the same water pump my PCM does, you want to insert the gasket into the female side of the pump (in the groove on the part you removed) and not around the male side that has a lip (you can see it in the picture you took). The gasket needs to be crushed in that groove so it won't suck air.

Mine sucked air and I burned up an impellar on the trailer with a fake a lake. Run as Mike suggested, if you impeller is working nearly 100% of the water will be sucked up by the impeller (ok not 100% but it should be very noticeable that it pulling the water).

[Z3CO23]

Here is a picture of my impeller. I have the 343 in my RZR and we threw an impeller while we were on our vacation at LOTO. The impeller in the picture had 30 hours on it and I also have a strainer. What I have found on replacing the impeller you have to make sure the splines of the impeller get turned the right way. The impeller obviously goes in either way, so once you get it in and get the assembly back together you have to physically spin the housing towards starboard with your hand. You will actually be able to hear the splines "pop" or flip as you rotate it with you hand slowly. This insures that all the splines are facing the correct way and ready to rotate toward starboard when while underway. If you don't get the splines flipped and facing the right way then it will forcefully try to do it when you put it under power and more than likely your going to damage it immediately. It wont initially damage to the point where your temp will jump immediately but it will get worse rapidly. I was pulling my hair out until I figured out the spinning with your hand step.

[Paxdad]

How are you putting the gasket on the housing? Assuming you have the same water pump my PCM does, you want to insert the gasket into the female side of the pump (in the groove on the part you removed) and not around the male side that has a lip (you can see it in the picture you took). The gasket needs to be crushed in that groove so it won't suck air.

Mine sucked air and I burned up an impellar on the trailer with a fake a lake. Run as Mike suggested, if you impeller is working nearly 100% of the water will be sucked up by the impeller (ok not 100% but it should be very noticeable that it pulling the water).

I believe when I replaced it i put the o-ring in the groove on the pulley side you are referring to. I will double check this time when I replace it once again. I use the zip tie trick to make sure the splines/ vanes are all oriented the same direction.
Thanks again for all the replies.

[boatdr]

Do you have the plastic sea strainer? If so check the fittings the can be loose enough to let it get air

[IDBoating]

once you get it in and get the assembly back together you have to physically spin the housing towards starboard with your hand. You will actually be able to hear the splines "pop" or flip as you rotate it with you hand slowly

You can and should do this as you are first inserting the impeller into the pump. The vanes will require a bias to allow the impeller to insert anyway, so just make certain they're biased in the correct direction and you'll avoid stressing them at all. That "pop" sound means you're dramatically overstressed the vanes by forcing them first one way, then BAM to snap over to the other way. No reason to do that when it can so easily be avoided.

[Vicseek]

I replaced an impellor this season (figured 3 years was time to do it)...engine overheated due to impellor breakdown around the 10 hr mark. I generously lubed up another one with a silicone lube, installed by turning the impellor by hand as it slid into the housing and BAM..50hrs later she's doing fine. In my situation i never lubed up the first one I installed...These things need some lube for that inital run! Hope your problem is a simple fix.

[Paxdad]

Wanted to circle back to close the thread on my findings. After pulling all hoses off, back flushing entire system (with exception of removing the exhaust risers the only thing I can conclude is that the thru hull valve was partially closed. I even went as far as placing a clear section of hose from Home Depot on the discharge side of impeller pump to check for signs of an air leak. Nothing found. I expect the pieces of shredded impeller passed out the exhaust. Installed new impeller and ran it a few hours and then did a visual inspection and all was perfect. I plan to inspect it again at the 10 hour mark just to be safe.

[Paxdad]

I have come to find out that the two impellers that shredded are now know to be from a defective batch of impellers. Even though my PCM is in a 2008 SANTE (Nautique) it is the same motor in many of the Tige boats. Hopefully this will help those with PCM 343 motors that may have experienced the same problem. My parts supplier (Nautiqueparts) said it was for impellers that sold during the first half of this year. They are standing behind my purchases and sending me two replacement units. The impellers are made by Sherwood who is the manufacturer of the pump for PCM.

[IDBoating]

How can we tell which impellers are faulty? Who told you about this? More info, please. One of my worst nightmares is chunks of impeller stuck in my engine block.