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Water pump for gas boat

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Old 12-28-2018, 05:30 AM
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vuuli312
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Default Water pump for gas boat

Hi.I was wondering if someone could post some pictures of the inside of the water pumps used to cool gas engines. Id like to see if its possible to make one .I know they operate from engine vacuum using a diaphragm.Thanks to all.Im converting a 4 cycle trimmer to marine use and need a water pump to circulate water to the water cooled head.One other question, does a 4 stroke create enough vacuum to run these pumps since these pumps typically are used on 2 strokes.thx
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Old 12-29-2018, 02:42 AM
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Tidnab
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Here's some info from the Walbro site. FPC-pump-8-20-12.pdf
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Old 12-29-2018, 06:44 PM
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Unless you will be sitting idling with a clutch? You do not really need a pump. Even if you had a clutch you do not really need one unless sitting and not moving for a bit.
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Old 01-02-2019, 06:19 AM
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As mentioned above - the requirement of a water pump is not critical as long as the boat is not left idling for too long - movement of the boat (or the thrust from the prop - depending on your setup) should flow sufficient water at modest speeds.

The pulse pumps we use are actually used as fuel pumps on larger 2 strokes like jet skis etc. https://www.ebay.com/sch/i.html?_fro...lbro+fuel+pump

That said - I am not sure a pulse type pump would work well with a 4 stroke as I don't believe you will see the same pressure pulse in the crankcase as the 2 strokes do. A belt driven pump like used on the Blata 40 motors might be one option - another option might be to use an electric pump (like a windshield washer motor or similar). You may also adapt an aquarium or fountain pump to suit your needs - https://www.ebay.com/itm/Ultra-Quiet...-/392158991138
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