Duffy Electric boats....?

I honestly feel the boat is worth the time I'm putting into it. I enjoy learning, and this is something I've never worked on before. I'm only into it 5 hours. I don't plan on marking up parts and, I'm only charging my labor. The owner has given me a fair budget to get her running and I think it's doable. Yours is the only feedback I've gotten on this project Norseman and I appreciate your insight. I'll keep posting pics as I go along. Thanks so much.

-Matt

Hi, first off thank you for your response.
"my guy", was a grammatical error, my apologies.

My mentor and friend of 10 years,(also the person who referred me for the work on this Duffy) owns the machine shop that I have honed my how to "fix stuff" skills at over the last decade. He referred me to a gentleman named "Wally Fox", who owns and operates an electric motor shop one complex over.

When I drove the over to the shop for the expert to look at the motor, he explained to me exactly what you just said. The broken off spring part keeps tension on the brush,( which looks like a square magnet with a wire coming out of it, the wire leads to the posts which are labeled a1 a2 s1 2. I asked him if he could "rebuild it", and his reaction was "you've already done three quarters of the work", gave me the address to a shop a few miles away that has the parts or can order em and told me to use some Emery cloth to polish up the center where the brushes rub against....it's late, don't have pics of motor apart cuz it's still in vehicle and I didn't bring it in, I'll take some tomorrow through.

Thank you so much for the name of that bearing. I spoke with Duffy on the phone, but they weren't going to give me any info without a hull ID. This isn't a rush job, I work on it around my schedule so I haven't been up to the boat since pulling the motor.
With the research almost complete I am chomping at the bit to get these motor parts.

I sand blasted the pully today while at the shop, the numbers are way more legible now.
THANKS again for the info I'll keep posting pics as I get it back together.

Hi Guys,

Nice to meet some fellow Duffy owners. I am the recent owner of a Duffy 21 Cruiser from 2006. Since buying her in mid winter, we have run her a few times and more frequently now it's warmed up a bit.

Love the boat but few troubles along the way.. (I know.. it's a boat!)

I am really interested to know what temperature your motor runs at. Since my purchase, I have always thought it was running too hot, but of course the previous owner said it was normal.

I was recording 150 C (300 F) after a few hours running, with the heat gun on the casing so decided to get it checked. The mechanic said it looks like it's been running too hot for a long time and took it away to find the field windings were burned out. I had the motor rebuilt and told it was good as new.

Since reinstalling, I added an extra ventilation fan to the console and the mechanic said the motor would run at a temperature you could keep your hand on.
After a few hours running, it was back up to 150 C! Pretty frustrating.. He now says he has to take it away again. I wish I had just bought a new motor for the same price and waited a bit longer for delivery to Netherlands.

The motor type is EH4 4001. Is anyone else running this motor, and have you checked the running temperature?

One other thing, since the mechanic reinstalled the motor; there is now a knocking sound coming from the prop shaft with every revolution (maybe from the cutlass bearing- you can also hear it outside the boat and I have checked the prop is clear) has anyone else experienced this and if so, are there any fixes while she is afloat?

The mechanic tightened up the drive belt much tighter than I would and he said it's supposed to be as tight as possible, so I am wondering if that could be it, pulling the shaft a bit out of line.

Anyway if anyone could shed some light on these issues, I'd be most appreciative!

Thanks!

Look at the motor dataplate. It should show a "Class" letter, probably an H in your case. That tells you the temperature rating of the insulation. If it is class H then the motor is rated for a temperature rise of 125C or a maximum operating temperature of 180C. Temperature rise is the increase in temperature above ambient with a maximum ambient of 40C.

Since your motor has been rewound by what sounds like a small entity, the insulation rating may or may not meet original standards. Ask your rebuilder about the insulation class.

Bottom line is some electric motors run hot, what many people may consider very hot. Cooling is always a good idea and if you can do it, increase cooling by way of a water jacket (coiled tubing wrapped tightly around the motor) or finned heat sinks bonded to the exterior.

BTW, "as tight as possible" is the best way to destroy the bearings on both the motor and shaft.

Thanks for the words of wisdom!

I agree but have a little way to go to reach perfection in my Duffy, but I'll get there in the end!

I read most of the thread- very interesting thanks for taking the time! I will read through again later, but didn't come across any other mentions of running temps, except for yourself.
I did note your high running temp resolved by adding an extra fan to the console, which I did, but no luck which a reduced temp. I now have one intake fan blowing fresh air at the intake of the motor and an extractor at the outlet of the motor.

Adding water cooling is a good suggestion, thank you. Although I would think Duffy would have sold the boats with the motors running at a reasonable temperature, without the need for adding water cooling.

I will be sure to slacken off the belt and ask the mechanic his theory of making it so tight.

I too noted that Class H (which my motor is) is capable of a temperature rise of 125 Celsius. Max 180 C. That's why I wasn't too worried before, but after some trips, the motor really smelled too hot, so my mechanic took the motor to a specialist who found the field windings were completely black and burned. I saw the photos and it looked pretty bad, so I had these rewound.

The rotor windings remained fine, which is apparently unusual. The overheating of the field windings is still the issue, and seems to be caused by a too high current (80 Amps) which is measured under high load through the field windings, (this goes beyond my knowledge as to whether it is too high, unfortunately).

It is now suggested that the controller (Zapi SEM1) could be causing this high current. Zapi say this is unusual but possible.

Final checks are being done again by the motor specialist and if all is correct, Zapi suggest a new controller will be the best solution, since fixing it will require returning to Italy and getting it back a month later! (It seems the Zapi service centre and distributor here in Holland have never had this issue and does not know how to fix it!)

This leaves me wondering if it is just a very expensive process of elimination.

Hoping to have this resolved soon without being bankrupt!

The noise that I mentioned with each revolution of the prop shaft seems to be coming from somewhere in the stern tube?? Now that the motor is out, I can turn the prop shaft (very freely) by hand and each time it turns, I hear a clink noise. Has anybody encountered this and taken the assembly apart, or know what kind of bearing is inside? I assumed there would be a simple cutlass bearing at the prop end, but now I'm not so sure. It sounds like the noise is coming from somewhere around the rubber tube..

This is the set-up I have:



Last question for now. Has anyone serviced the hydraulic steering pump? Mine creeks a lot when turning the wheel to Starboard. The model is Ultraflex UP28T.

Enough questions for now I think! At least the fridge works - time for a beer!

Thanks in advance for your input!

The motor for the 1990 duffy I'm working on is way older than yours, but when I inquired about having it rewound by a man I would consider an expert in that field, he told me that he didn't feel it was necessary.

I felt confident to change the brushes on the motor only after being told by the expert(and feedback from this forum) that it was something I could do at the shop I work at. I have experience, and the correct tools at my disposal.

"Small entity" is a funny way to describe a shop or person being dishonest. I like it.

I agree, new mechanic.

While the controller might have some kind of current limiting feature, it does not force current down the motor's throat so to speak. If the motor is drawing too much current it is because something in the drive train is creating mechanical drag, the prop is not properly sized, or there is an internal fault with the windings.

The motor may be overloaded and the controller is not limiting current but it cannot force more current than the motor needs.

A "tight as possible" drive belt can produce a high load because of too high side loading on the bearings.

Hello fellow Duffy owners. New/used 1992 Duffy 18' owner and new to the forum. Working through some small issues. Previous owner purchased a replacement battery meter, but did not install it. Duffy no longer supplies 18 volt battery meters. They supply only a 36 volt battery meter. When I checked the voltage on the connections on the original battery meter, it was 18 volts. I have no problem installing the new battery meter, but can anyone tell me where I can pick up 36 volts inside the pedestal instead of having to run new wires to the + and - terminals of the 6 batteries? I did find 36 volts on what appears to be a "relay" of some sort that is wired to the forward/reverse control. When the meter is wired to it, the meter does read all the way to the right in the black. The batteries actually read 37.8 volts. So no problem for the meter to read full scale. When the motor is running slow, the meter barely comes off the right mark. When at WOT the meter comes down slighly. But as I slow the boat down, the meter needle moves back to the right. Should I be looking for a different location to pick up the 36 volts? Any help will be greatly appreciated.

So Norseman, did your original meter read 18 volts or 36 volts or maybe 48 volts?

What I don't understand is why on my boat the factory installed an 18 volt meter and the original wiring was wired to bring 18 volts to the meter when the motor is a 36 volt motor?