Bow Thruster Switch (Volvo Penta)

[HarrisonM]

Hello:

The bow thruster switch for my Volvo Penta QL BP800 thruster is going bad. One min it works the next it does not. Not to mention it is 20 years old and is due to be replaced. I found the part number but it is rare to find. Also I was told the way Volvo Penta wired the thruster it was pretty odd. I think the pos/neg are reversed or something like that.

Has anyone had any luck with another brand switch? I called a yard about it and they recommended I pull the boat and replace the entire thruster - REDICULOUS!!!!!!

I am hoping someone messed with this and can share.

[Wotname]

Those switches look very common; 99.99% of all switches are replaceable with off the shelf switches. All you have to do is confirm the contact action, the volt/current rating and terminal type, then buy a similar switch.

I haven't got QL BP800 manual but I'll look for one later when time permits. The schematic will usually show all the necessary info to source an aftermarket switch.

Others may already know of a suitable replacement without looking it up!

[HarrisonM]

Still working on this. I did manage to find a schematic of the switch with part numbers. I may have to do an old fashion "rebuild" of the switch. See below link on page 56-57.

https://www.marinepartsexpress.com/V...PARE_PARTS.pdf

[AndyEss]

It is probably a bang-bang (on/off) reversing polarity switch. Those are common in various industrial tools and machines. Take a look at the McMaster-Carr site for DC reversing switches.

[HarrisonM]

Hello again... Thank good for eBay!!!!!

I really just wanted to replace this switch, but I found the 2 key switches on eBay. I am going to disassemble it and rebuild it. I also need to paint the gauge face. I am planning on using some good Rust-Oleum paint for the panel assembly, but I also need to paint the arrows and logo. I guess I could used Testors paint for that. Does anyone know if there is a special paint I should use? It is not in direct sun light but will still get a lot of UV even if I cover it.

A friend of mine has a Cricut machine.... I am also thinking of making stencils via sticker paper and then using white spray paint for them?

[tkeithlu]

Reversing motor switches, toward the bottom of the catalog page below, generally are pretty big - I've got one on the dock hoist for my run-about boat. But, then again, you've burned yours up because Volvo-Penta didn't supply one with the ability to overcome arcing in the first place. You could go with any number of switches higher on the page, by current rating, or you could decide to improve on the situation.

Most important, Volvo-Penta didn't design and produce the original. They took one off the indstrial shelf. You need not pay there price for a similar, or better, replacement.

https://www.mcmaster.com/forward%2freverse-switches/

[tkeithlu]

I used to know a surveyor (land type) who had been a petty officer on a USCG cutter that was a retired mine sweeper. It was rated to stop from flank speed in 1 1/2 lengths, by the simple expedient of switching the electrical field in the diesel-electrric drive. They tried it. It worked. It buried the fantail under the water, but it worked.

[Wotname]

OK, finally got back to this thread

Your switch panel shows two switches, a single pole push button ON/OFF switch and a single pole toggle (ON)-OFF-(ON) switch (i.e. the port / starboard switch). Both switches are low current switches (say less than 5 amps)

BTW (ON)-OFF-(ON) indicates a centre OFF position and two momentary ON positions.

Both switches are commercial off the shelf items (COTS), cheap and are readily available.

Assuming it is the port/starboard toggle switch which is faulty, you need to look for a toggle switch designated as a SPDT (ON)-OFF-(ON). Alternatively a double pole switch [ DPDT (ON)-OFF-(ON) ] is also suitable; you will have a spare set of contacts (poles) for future proofing

Looking at the helpful McMaster-Carr link provided by tkeithlu you will find several suitable toggle switches -

8002K98


or for a more robust Mil-Spec version 8002K119

https://www.mcmaster.com/forward%2freverse-switches/

If you are rebuilding the panel, you might want to replace the push button switch as well.

[HarrisonM]

Thanks for the replies.

I purchased the switches and they are on the way. I am going to remove it and do a complete rebuild of it including repainting it. On another note I did find a site called UpFix.com. They specialize in repairing auto electronic parts. If you have something old and you can't fix it yourself they may be worth a try...

[HarrisonM]

Thanks for all the great replies....

I finally completed the rebuild of my bow thruster switch. QL is really no more... I found a schematic of the switch. I could have gone with standard off the self parts, but I found them on ebay and just decided to go with them. I installed it today and it works perfectly! I am so happy with it!!!! See pics of the final product....

On to my next project