SidePower Thruster Prop Shaft Corrision

Hey all. I recently pulled the prop on my SidePower SP55S bow thruster and found that most of the threads other than those under the nut securing the prop had corroded away. Not sure why other than perhaps the PO did not keep up regular anode changes. I removed the prop to upgrade to a new 5 blade model. I checked the parts listing for the thruster thinking that I would order a new shaft and pop it in. No such luck. The only part available is the entire lower unit at a cost of $649USD. Before I go ahead and order this does anyone have experience with this issue and is there a solution?

Have you talked to Imtra support about it? I used them this week to help find a problem with mine. 508-995-7000

Comodave said:

Have you talked to Imtra support about it? I used them this week to help find a problem with mine. 508-995-7000

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I spoke with Imtra and although very helpful, they did not have a solution other than purchasing the entire lower unit. I’m going to try tightening down the prop with the remaining threads on the shaft. If it feels secure I’ll loctite the nut in place and cross my fingers. Hopefully get a season out of it and then I’ll order in the replacement.

Probably the zinc being neglected. I've got near the same unit and the zinc is about gone in two years.

Also when installing my unit (twelve or so years ago) the instructions were specific to not connect the gearbox to boats bonding system. You might look into that. Maybe ask the MFR about that as well.

Ski in NC said:

Probably the zinc being neglected. I've got near the same unit and the zinc is about gone in two years.

Also when installing my unit (twelve or so years ago) the instructions were specific to not connect the gearbox to boats bonding system. You might look into that. Maybe ask the MFR about that as well.

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That is my understanding as well. Their alum anode protects the unit independently.

If that shaft will come out and go to a machine shop perhaps they can turn the rusted area down one size for a second nut. Like if the original nut is 9/16 maybe you could rethread part of the shaft to half inch.

But then again by the time you screw around with the project you might just be better to buy a new one.

pete

Yes, do not bond the thruster with the main bonding system. It is independent.