outboard engine - testing on land with water muffs

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deising
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outboard engine - testing on land with water muffs

Post by deising »

[I was going to post this in the Outboard Engine section, but it is so full of posts and I could not use search terms like 'water' and 'pump' as the software deems them too common.]

I learned something new about outboard engines over the past few weeks. My Suzuki 9.9 needed some TLC, so I mounted it on a modified hand truck for servicing. I wanted to run it when done without the hassle of moving it back to the dock, mounting it on the dinghy, and then hoisting them into the canal water. I especially did not want that approach since the motor would have to be brought back to the garage for storage. So, I figured a nice set of water muffs with a garden hose over the intake on the lower unit would work fine. It didn't, at first.

I was careful to shut off the engine after a few seconds of no water exiting the "pee" hole, and had lubed the impeller before reassembling, so I was not worried about impeller damage. The short story is I took it all apart again to verify all the tubes and passages were open - they were. When I tried running it again, I pushed the muffs tight by hand to seal much better than they were. Within a few seconds, water was coming out the "pee" hole. I removed my hands and let the muff leak as normal, but the water still flowed through the system.

The conclusion is the leakage was not allowing the water to rise up inside the lower unit to the level of the pump intake and therefore it was not pumping. Once primed, the pump continued to move the water through the cooling system. I had also tried using a plastic container as a short "test tank" but that water level was not high enough, either.

Here's hoping this saves someone else the hassles I had.
Duane Ising
m/v Diva Di
Punta Gorda, FL
2006 PDQ MV 34 - hull 91, 75HP, 3-blade
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Re: outboard engine - testing on land with water muffs

Post by Phenix-former-owner »

This is also my experience when running the Yamaha 9.9hp with muffs. It takes more water to get it primed. I have switched to using a container of water to submerge the lower unit in (my large kitchen garbage can is the perfect size).
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