Impeller replacement

[Bob Schwartz]

I recently got an engine light motoring back to the marina and had to get towed in. It was the impeller. Three of 6 wipers had failed. One of the failed wipers broke off and clogged the output port of the pump and blocked all water flow.

I replaced the entire water pump and impeller about 5 years ago and have no more than 300 hours (max) since then. The owner's manual for the Yanmar GM-1 calls for replacing the impeller every 1,000 hours. That is ludicrous. Realistically, most engines do not get 1,000 hours of service for the life of the boat/engine.

Active bass fisherman usually replace the impellers in outboard engines once a year.

I was wondering, how often should the impeller be replaced in small diesel engines? One thing for sure, a $10 impeller is much cheaper than a new engine.

Good sailing (& motoring)

Bob

[Duncan]

...I was wondering, how often should the impeller be replaced in small diesel engines?...

I think the usual practice is to at least inspect annually.

Of course, if you're inspecting, you might as well replace it while you're at it.
You can always keep the old one for a spare.

[sgbernd]

I started replacing them annually but have dropped back to 2-3 years. Whe I inspect the old one, usually they are fine and could go another year, once I saw a bit of cracking starting near the hub and vane but it could have gone another year as it was nowhere near failure. I put 55-60 hrs a year on the diesel and about 10-15 on the outboard (same replacement schedlule). In my case, the cost of the impellor is trivial ($20) but the trouble to install it is painful due to the difficult access. I have owned the boat for more than 12 years now and have not had any trouble with the impellor.

[Bob Schwartz]

Sgbernd

I had installed a Speedseal cover so that if I had to replace the impeller at sea it would make the job easier. When I recently replaced the impeller it worked as expected.

Here is the website:

www.speedseal.com

[Carl Thunberg]

Just a bit of friendly advice when ordering a Speedseal, if you choose to. You need to specify the correct water pump, but you also need to specify which direction it should slide. On my previous CD30, it made a significant difference which direction the Speedseal should slide (left or right). I did not specify which direction it should slide and sure enough, it was machined to go the wrong way. As such, it wasn't any better than the old cover. It was my own fault for not specifying. Hopefully someone else can learn from my mistake.