Melted Impeller

[zorak]

Hi all. I need a little help. Late last year i replaced the impeller in my classic 50 and had a good telltale stream. To make a long story short,i was at the ramp and got in a hurry and fired up the motor out of the water. Took about 15 seconds to realize what i had done. I still had water coming out of the telltale at idle although not as strong. i think i took it out once more and no problems. I then pull it out last weekend ,put the muffs on and no stream. i dissasemble the water pump and the impeller is melted bad. After looking i determined that i overtightened the upper water pump housing and distorted it. Would this alone be enough to nuke the impeller? I did lube it originally upon assembly. Any thoughts ,experiences ,observations or butt chewings on this one?

 

[capslock118]

Re: Melted Impeller

Would this alone be enough to nuke the impeller?

Yup but I imagine you running the engine out of the water for 15 seconds had something to do with it too. It only takes a couple seconds to burn out the impeller.

Personal story: Two seasons ago I was closing my engine for the winter and I realized I forgot to turn the water on for the muffs. Following spring the teltale still spewed water so I thought I was ok. Turned out, and I only realized this when we were out on the water, the impeller was in good enough shape for RPMs lower than 2500 but could not push enough water through for any higher RPM. The result was the engine overheating past 2500 rpm. I realized that the water impeller kept the engine cool enough at 2500 rpm or less so I was able to push slowly home. Not exactly the most fun first-outing of the season.

The service manual provides specific max torque for tightening bolts on the water impeller; follow them.

 

[zorak]

Re: Melted Impeller

Oh believe me,i know i screwed up. Sounds like you had the exact same scenarih well,live and learn. Thanks for the input.