Motor swap and other upgrades

Captn' Spalding

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Adam
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1976 Unknown Novi Skiff
On the last fishing run last year the outboard started to act up. Lost of extra water out of the exhaust port and way down on power. I inherited this from my father-in-law, and while he loved this boat he was not into preventative maintenance. After seeing how rough the motor truly was, I started to shop around for a replacement motor for my Novi skiff.

Problem I ran into was that I needed at least a 40 hp and tiller. I dont have a ton of brand loyalty, but I am most familiar with Yamaha. In the end I finally found a younger fresh water Yamaha 40 hp that ran well and had some recent service. I had to buy a new tiller, but at least when I am ready to go to another motor, all i need to do is get the fit kit.

This past weekend I started the swap. Here is the boat and old motor.
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Since the inheritance, I had to so some minor glass work. The boat is overall in good shape and the surprisingly sound. It was not free of issues however. There was a seam that had opened over the years. Other than that some light cracking and poorly addressed holes and sealant. I addressed the separated seam to the motor, but everything under the outboard pad was left alone.

After pulling the motor I confirmed that the separation continues under the outboard pad. I can fix this without much issue. I was very surprised that it was not in worse condition.
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After doing some additional measurements, I cannot use the old mounting holes on the new motor. I was hopeful, but nope. Filled the old holes with Hawk Epoxy with their FI high strength filler. Luckily the new outboard mounting is much wider. So I will be clear of the holes.
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While I am back here I am trying to figure how to install a collapsible ladder and scuppers. There are two drains located on either side of the transom. That is the floor height. Normally I put plugs in the drains, but would scuppers work in this situation? There was a couple times last year a rogue wave came over the stern and I then had to scramble to get moving and drain the boat while on plane. Ball? Rubber flapper?
 

Captn' Spalding

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1976 Unknown Novi Skiff
Its been a busy month for me since I started this swap project and I wish I had a little more time and I would likely be farther ahead. I am happy to say the glass work is done. The separation is now sealed up well. Since I am so behind I just want to get the motor mounted and any additional modifications can wait till later.
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I gel coated over that repair on both sides. I have had good luck doing that over epoxy. I put a coating down to the line. Eventually I am going to paint so didn't bother tinting anything. At this rate paint wont happen till next year. A little before and after. Looks okay after sanding out the elephant skin. Show boat quality...no, but this is no show boat.
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I am now ready to start the mounting process for the outboard. Here is where I need a little advice. I know there is flexibility here, but this is my first time doing this, so I want to make sure I do it right.
I know that I should aim to have the anti-cavitation plate in line with the bottom of the hull to reduce the lower unit drag. This means I need to have the motor spaced about 1.25 inches above the top of the transom to do that. This places the water pickup at least 3 inches below the hull, so this should be okay. This arrangement is similar to how my old Yamaha 40 was mounted. Unfortunately I didn't take any measurements prior to removal to help me verify that my install process is correct.

Here are some pics as it currently sits. Doe this look correct or good? Anything I should do different?

1.25 spacer - I think I would use the 3rd bolt hole down, and that could allow me to raise the motor or lower the motor about .5 inches if I need further adjustment.
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Anti-cavitation plate in line to the edge of the hull.
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My hull has a slight rake to it, and if i hold the straight edge along it, the anti-cavitation plate seems like it may be mounted a little too low.
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One more shot holding the straight edge along the hull and where the anti-cavitation plate falls 20210718_135819.jpg
 
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AJ2020

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Casco Bay
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Duffy 35
Looks pretty good. Run it and see if u can see if the anti-cavtitation plate is riding right. Just raise it or lower it if need be...
 

Captn' Spalding

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Adam
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1976 Unknown Novi Skiff
That is what is bothering me...it looks pretty good, but not sure if I am doing it right.
I want to try and set the motor just about where it should be and have a little flexibility in fine tuning if needed. I dont want to go too low or too high.
If I use the 2nd hole, then I could drop the motor around .5 inches or raise it up an inch.
If I use the 3rd hole, then I could drop the motor around 1 inch or raise it up a .5 inch.
 

Toolate

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I would go up a bit. This is not a high performance boat so shouldn’t matter. (Generally cruising under 20 I am guessing)

LOTs of threads on this on THT not so much here
 

Captn' Spalding

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1976 Unknown Novi Skiff
What do you call a bit?

She zips along quite well with the 40. I dont have any nav on it but i think the Garmin I was using was getting in the 30s WOT.
 

Toots

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Get the plate as close as you can, and leave yourself some room to adjust both ways. 1 inch should be plenty and dont stress too much about it

Nice job on the glass work, it looks great.
 

Captn' Spalding

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1976 Unknown Novi Skiff
Thanks. To me the glassing is the easy part. I really like the epoxy over standard resin. Set times are shorter since I am using the fast-set. While I like the smell of polyester resin, I like not having to wear a full respirator for sanding. Overall, it's smooth enough for a work boat. When I get ready to paint it, I will do a little more sanding but for now I dont want to burn through the gel coat as it is not very thick and the epoxy yellows with UV exposure.

I think I am going to raise up the motor another 3/8 of an inch to get the anti cavitation plate truly in line with the hull. I likely will only be able to raise or lower the motor 1/2 inch or so doing that but I think I will be at the best starting point I can be at. This transom is made for a long shaft since it measures 20 inches, and the motor is a long shaft...but i wish I had an inch or two more to work with.
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Cool Boat

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That is what is bothering me...it looks pretty good, but not sure if I am doing it right.
I want to try and set the motor just about where it should be and have a little flexibility in fine tuning if needed. I dont want to go too low or too high.
If I use the 2nd hole, then I could drop the motor around .5 inches or raise it up an inch.
If I use the 3rd hole, then I could drop the motor around 1 inch or raise it up a .5 inch.
I've done a lot of skiff motors, too low makes for a wet spray situation at the motor. I would agree with your thoughts to use the second hole. And as someone else noted, from the pictures I'd raise it up a bit to start. Make sure that the motor tilt angle is maybe close to 90 degrees when using the straight edge. I believe the only reason to go lower would be if there was a handling problem with the hull design, otherwise I would believe the higher the better for efficiency and performance. It's not over critical. Get it close and you will do fine. Good luck.
 

Captn' Spalding

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1976 Unknown Novi Skiff
Thanks for the advice. I will do a bit more measuring and bump it up a little more.

The boat handled well enough last year with the old motor and it was set rather low. You can see from the first pic of how the motor was mounted. I suspect anything I do should net an improvement in efficiency and speed. Hopefully this will help in getting up on plane a little easier. Plus now with a power trim I can make some adjustments on the fly. Old motor couldnt do that.
 

Captn' Spalding

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I went away to help some family last weekend and got back on the project this evening.

Before I break out the drill bit. How does this look? I know I am over thinking this, but the previous motor worked fine, and my father-in-law just hung it over the back and drilled 4 holes. I am using this as a learning experience for my next boat.

I took peoples advice and mounted the motor a little higher. After a few measurements I decided on 1/2 inch higher. The anti-cavitation plate is now just slightly above the bottom of the hull and the motor is about 8 inches back from the hull. I still expect it to sit a little below the surface when running, but that wont be too much of an issue with this boat.

As for drilling I was going to drill the 3rd hole down. That would give me enough spacing from the edge and meat on the transom. That would leave me the ability to raise the motor 1/2 inch if I want to play with it for fine tuning. or if there is really odd issues with the motor being mounted this high, I can drop it down about a full inch.

I really appreciate the help and advice!


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Captn' Spalding

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1976 Unknown Novi Skiff
Weekend Progress:

Crossed fingers and drilled the holes. 1/2 in SS hardware from McMaster Carr. I went with some very oversized fender washers to make sure there was a little more distribution. This feels pretty robust since the previous motor used 5/16 hardware.
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I also added a ladder and hand grab so it is easier for the family to get into the boat. The brass folding foot tab never worked and I tweaked my foot pretty bad trying to use it one time. I wanted the 4 step, but that appeared to be completely sold out nation wide no matter where I looked. It fits well with the back of the boat and seems robust. Eventually the brass foot peg will go, but not going to worry about that for now.
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I am happy with how things came out overall and I appreciate the input from members. It is a little nerve racking to do something like this for the first time. I still can raise the motor about 1/2 inch if I really want to, but I think It is going to sit like this for one main reason. That being the transom is a little more wet than I previously thought. I am pretty certain that I will get 3-5 years out of her as she sits...maybe more. I will have to watch for stress cracks and fatigue, but will have to tear into it for a replacement sooner than later. Luckily it is a simple boat overall and it may be something I can tackle.

Next step is electrical. This boat hasn't seen electronics for some time, and I need to wire it up from scratch. For now just a battery but lighting will come as well as bilge and nav/fish finder.
 

Captn' Spalding

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Got the battery mounted in the bow and ran the power cables. 2 ga. positive and ground with a 3-way battery switch. Eventually if I get out for some evening fishing I will install a second battery but will run with this for now. The switch is tucked nicely so it should stay relatively dry. 20210814_193941.jpg
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Ran the fuel line in the old location. I may swap it to the other side, but the primer is still close by and convenient. I want to get a canister filter rather than the inline one I have currently. Just need to figure out the right one to get so that when this motor craps out I am well set for a 4 stroke. Fired up the motor and she started pretty quickly and ran well. Idle is a little lumpy, never got to do any adjustments after I installed the tiller. I hope the oil injection is working correctly, this is the first time I am not mixing fuel.

I swapped over the prop from the 40hp that came off my boat. That prop was an aluminum 11.25 x 14 and pushed the boat very nicely. The prop that was on the new motor is an aluminum 10 3/8 x 13. Not sure what will push this boat better. I am going to grab my pocket Garmin and see performance differences. I honestly have no idea what the best all-around prop for this motor is. If all goes well, hope to get to Mystic next weekend for the Wooden Boat Show.

Any advice on who makes a good portable tank? I have 2 that are around 6 gallons each. They are old and its time for a replacement. Are the Moller 6.5 gallon like the one below decent?
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I may have the space for their 9 gallons tank like the one below That would be a better use of space under the front seat. Thoughts?
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tsharac

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If you can do two six-gallon tanks, I'd do that. When one runs out, you know you have another six-gallon to get back. With one tank, when it's empty, you're in trouble.

The best fuel tank I've seen are Dura Tank, they seem to have stronger sidewalls and are a better shape for fitting into tight places. I also have a Moeller like you show, it works fine, too.
 

Captn' Spalding

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1976 Unknown Novi Skiff
I'll look into that dura tank. Thanks. I run two 6 gallon tanks. That has worked well. I'd also consider two 9 gallons if they fit well.
 

Captn' Spalding

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Launched from Barn Island, in Stonington. Motored past Napatree Point out to Watch Hill. Tooled around Sandy Point and the surrounding area. All in all the new motor ran well. Put on about 17 miles all together.

Ladder worked like a charm and let the family get in the boat much easier.

The motor is mounted rather well as is and I am not going to play with it any further. While underway at speed, if I do any trim adjustments upward it starts to suck in air. Overall spray patterns looked good so not kicking up too much water. It was too choppy for pics/vids. No proposing or odd behavior. And best yet, motor stayed on the transom!

I swapped the props. My hand held Garmin was showing that I was in MA for a good part of the trip, and when I was finally showing up in in the correct location, I was bobbing around on an island. Not about to trust any figures from that device...had to go with seat-of-the-pants instead as there are no gauges associated with this setup. The 11.25 x 14 seemed to net me the highest speed. The 10 3/8 x 13 seemed a little slower overall. No idea on RPMs. I didn't note a huge difference in hole shot, as I never really do that...I tend to ease into things on this boat. Its nice having a couple props on hand for this motor, but I really dont know what I liked better. This hull is not built for speed, maybe I need to find a good middle ground between the two.

As for fuel economy, I probably went through 2.5-3 gallons, and that had me motoring around much of the morning with the family. My second tank started leaking almost immediately, so definitely time for new tanks.

On the deck for the next phase of the project. Lights/radio/and switch panel.
 

Captn' Spalding

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1976 Unknown Novi Skiff
This thread has evolved from more than just a motor swap. So I figured I would edit the thread title to something more appropriate and continue updating as I work on things.

What do you do when a hurricane approaches? Make some cushions. The family made had some complaints of a rough ride, and I knew I needed to add some plush improvements for derriere comfort. I priced some custom cushions and I :eek: at the price. The seats are 10 inches wide, and I would have needed one at around 48 inches and another at 53 inches. I couldn't justify a few hundred dollars for vinyl wrapped foam. I picked up some 3 inch foam, vinyl, 11.5 inch wide PVC board, glue and stainless staples. Here is the end result: Ta da.
Pretty...no. Functional...yes. I am no seamstress but these should work well enough. There is one 2 5/8 hole in the base so they have a place to breath out. They way they are wrapped should keep most moisture out. I was going to screw these down from the bottom but am now thinking I will use a couple cam-buckle straps to cinch these in place. This way if they get covered in fish blood, it's easy to clean. They have a nice carbon fiber weave pattern too. Now I have to figure out a seat for myself.
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Big thank you to forum member Wharf Rat in his advice, price, and quick shipping for a radio. In the next couple of days I will have in hand a Standard Horizon GX1400G. Unfortunately I ordered the Shakespeare 5400-XT 4 ft Galaxy Antenna and ratchet mount before he was able to put his hands on one, but looking forward to getting this installed before the next outing. The new 6.5 gal Moeller tanks are sitting in the barn ready for fuel.

I was going to install the radio in the forward bulkhead, but am having second thoughts. Before I cut a hole maybe I should consider building a console that puts a switch panel, radio, and chart plotter/fish finder in close reach. Since this boat is a tiller I'm locked to the stern most of the time. I thought it might be good to install something behind the back seat. This would either be central to the seat or off to the starboard side gunwale that is within my reach. Radio and plotter will likely be flush mounted if I build a helm. There is one thing that I have to try and work around. This boat has oars and oar locks. I would like to try and keep the functionality of this feature and be able to row in an emergency. Anyone see anything like this? Thoughts?
 
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