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Yanmar 3gm30f water pump

Posted: Thu Dec 06, 2018 11:42 am
by Camino
PITA - yesterday i changed out my impeller to the 3gm30f. This is only the second time I've changed it - do it about once a year. The water pump is really difficult to get to - I have to remove the water pump completely to be able to get to the impeller. Doing this while underway seems like a recipe for disaster for the time it takes (as a single hander I'd need to be heading straight out to sea to do the task). Any one have any impeller tricks to share. I read once of a water pump rotation kit where the water pump is flipped around, facing forward..... don't think I'd have space however for that..... Suggestions?

Re: Yanmar 3gm30f water pump

Posted: Thu Dec 06, 2018 1:00 pm
by gamayun
I have no suggestions for you, but curious what others say because of how long over due mine is. I think once a year is too frequent....six years is pressing my luck.

Re: Yanmar 3gm30f water pump

Posted: Thu Dec 06, 2018 3:37 pm
by RadioZephyr
Perhaps installing a Speedseal?

Even though my water pump faces forward and I can easily access the impeller, I installed one because I like the teflon disc that lets the pump run dry without burning up.

Re: Yanmar 3gm30f water pump

Posted: Thu Dec 06, 2018 7:58 pm
by Camino
RadioZephyr - speed seals would cut my time in half I think ( still have to remove the water pump) but I believe the company closed. Anyone know of a substitute?

Re: Yanmar 3gm30f water pump

Posted: Fri Dec 07, 2018 4:12 pm
by ketch22
YOYO for removing it, but I have a good trick to re-install.

First, lube up the spine and the blades of the impeller. Get yourself a rightsized hose clamp and collapse the impeller blades with it until they are small enough to fit in the pump housing with little or no friction getting them in. The clamp needs to be positioned so that you are covering just enough of the blades that you can loosen the clamp slowly, slide it off of the impeller blades ( the portion of the blades which aren't inserted into the pump housing ) and as you eaze the clamp off, keep pressure on the impeller so that it eases into the housing.

For knowing when to replace, I eyeball the exhaust water output primarily, and/or use engine hours for knowing when to replace, but in any case, never less than 2 years; except in the case of a suspected mud intake resulting in broken impeller blades.