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Old 02-18-2022 | 07:09 AM
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Originally Posted by TomZ
Yes, bad design in my opinion, too.

And impellers should last longer than just a season. I've run two seasons but that's about as long as I'd want to go without water pressure gauges to watch for degradation.
I agree, and I usually go two seasons also on my outboards. This is my first sterndrive and so far I really like it. Since there is a bit more maintenance to do than an outboard my goal will be to streamline it and make things simpler. This seems like a great place to start. Thanks for the info!
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Old 02-18-2022 | 02:32 PM
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You have plenty of room to work on yours. Mine is really close to the bulkhead, but they have a nifty little tool that slides in between the impeller blades and hooks to the back to pull the impellers right out. Nice on those hot days when you arse-up in the air changing an impeller at the lake! (don't ask me how I know! haha!)
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Old 02-19-2022 | 09:32 AM
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Originally Posted by Rookie
I bought these from Full Force this summer for my AT. Just sick of the Merc pumps leaking from the front seal and a pain to change the impeller.


i added closed coolant system several years ago...

added same pump...
works fine...





i found a range in prices...shop around got mine for 150 each but was 3-4 years ago..i also made made my brackets...for what they want for one ,,,i made two for half the cost..just some angle iron and welder...done

Last edited by flashgordon; 02-19-2022 at 09:39 AM. Reason: info
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Old 02-19-2022 | 12:54 PM
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I made the same brackets.
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Old 02-20-2022 | 10:17 AM
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Originally Posted by flashgordon
i added closed coolant system several years ago...

added same pump...
works fine...





i found a range in prices...shop around got mine for 150 each but was 3-4 years ago..i also made made my brackets...for what they want for one ,,,i made two for half the cost..just some angle iron and welder...done


i also had my machine cut a depression in lower pulley to help center pump.......
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Old 02-24-2022 | 08:11 AM
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Originally Posted by flashgordon
i also had my machine cut a depression in lower pulley to help center pump.......
I think this right here is going to be the key to making this work 100%. The holes in the johnson pump are 1/2" and the bolts are 3/8. The real tricky part is that the bolt circle on the johnson pump is 82.5mm and its 3.2" (81.38mm) on the pulley. To use the 1/2" to 3/8" spacers, there must be enough tolerance in them so that the bolts line up but that wouldn't center it perfectly. I think skipping the spacers and having a machine shop put a slight depression in the crank spacer is the way to go.
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Old 02-24-2022 | 06:01 PM
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I understand what you’re saying, but if you use the bushings that I provided, the bolt circle aligns properly. The spacer plate was only used to keep the pump body away from the pulley. Even with the long-shaft pump, the pump body ends up close enough to make hose fitment a challenge. The way I have it set up works really well and the slight wiggle I have witnessed is probably due to pump shaft tolerance more than anything. The way the angle bracket is bushed/dampened indicates that some movement is expected.
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Old 02-25-2022 | 08:04 AM
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Originally Posted by TomZ
I understand what you’re saying, but if you use the bushings that I provided, the bolt circle aligns properly. The spacer plate was only used to keep the pump body away from the pulley. Even with the long-shaft pump, the pump body ends up close enough to make hose fitment a challenge. The way I have it set up works really well and the slight wiggle I have witnessed is probably due to pump shaft tolerance more than anything. The way the angle bracket is bushed/dampened indicates that some movement is expected.
You're probably right. Sometimes my nerd brain gets in the way of just getting things done. Once I get it all apart I'll set it up with the bushings and see how it goes.
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Old 02-25-2022 | 10:00 AM
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I am wanting to do this conversion on my boat as well. I have the Alpha one outdrive. Would I just remove the impeller from the outdrive and run the feed hose from where it comes through the transom to the new pump? Also, I saw these water pump bypass kits and was wondering if these would work with this setup so I don't have to worry about replacing those engine mounted pumps anymore?
http://www.hardin-marine.com/p-14412...ut-bypass.aspx
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Old 02-25-2022 | 10:28 AM
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Originally Posted by chappy2330
I am wanting to do this conversion on my boat as well. I have the Alpha one outdrive. Would I just remove the impeller from the outdrive and run the feed hose from where it comes through the transom to the new pump? Also, I saw these water pump bypass kits and was wondering if these would work with this setup so I don't have to worry about replacing those engine mounted pumps anymore?
http://www.hardin-marine.com/p-14412...ut-bypass.aspx
He swapped because his seawater pump was hard to get to.
IMO, There's nothing easier than an Alpha impeller job as far as impellers go.
I find it hard you'd be at any advantage to go through the trouble of adding a crank mounted pump.
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