48 years...

[stan2076]

Or maybe the 0 to 1" dimension is to keep the upper part of the leg above the cavitation plate out of the water so it does not cause drag?

 

[stan2076]

Boat meet Motor, Motor meet Boat. I now pronounce you Motorboat!

 

[stan2076]

Hooking up the steering was a bit of a challenge. The old OMC used a standard cable but over the years someone had ditched the stock OMC steering system and fashioned a crude but workable setup. it involved a home made bracket welded to the outside of the engine bay that clamped onto the steering cable housing to hold it in place, then the cable attached to the side of the outdrive. To accomplish this the steering cable nut was cut off the cable. Last year I replaced the cable and cut the nut off the same way, leaving the cable like this.


With the Honda I needed the nut back but there's no simple way to do that, even with a new nut you can't slide it back on. My plan is eventually to go to hydraulic steering but for now I want to get the boat on the water this Sunday to test. I found this nut on Amazon and figured I'd find a way to make it work.



The plan was to split the nut and weld it back together on the cable. First I had to make something to hold the nut for the operations that needed to be done. I first threaded a piece of 7/8" round stock with the correct die to match. I don't know how I had a piece of 7/8" round stock but it was on my metal rack and saved me from having to turn down a larger diameter.


Then drilled it out so it could fit over the steering rod.


Then attached the nut clamped it to the bandsaw to saw it in half.


Once it was split I cut the "pipe" to length


After this I went back and forth between the lathe and the cable, clamping the nut halves together into the chuck to do some removal of material inside the nut to get it to fit properly on the cable using the threaded pipe I made to hold the nut in the correct position.


That was it for the night, the next day I ground chamfers into the top edges of the cuts on the nut removed the anodizing on the cut faces and instead of a rubber band used a hose clamp to hold the nut together for welding. A couple of my not so pretty welds later and it securely attached to the Honda. So that's one way to replace a steering cable nut. It's solid, and it would probably outlast the boat, but like I said my plan is to switch to hydraulic in the near future so it's temporary.

 

[stan2076]

Steering!

 

[stan2076]

Drilling with a stationary drill always seems counter intuitive but it is what it is. Lol

 

[stan2076]

Steering!

The creaking sound in the video is the trailer torsion axles not the steering

 

[stan2076]

Tank and battery installed. Turns out the tank is too far back and when tilting the motor it does contact the tank. Installed the controls, harness, fuel it's pretty much all rigged.

 

[stan2076]

Got the boat on the water yesterday, the motor stayed on and she might sit slightly lower in the rear than it used to but seems ok. I got very little propulsion though at different trim levels and RPM. Talked to a local propeller shop and they said that the 15 pitch should be good but it may not have enough cup in the blades. Dropping the prop off to them today.

Also found that the steering was reversed didn't think about that. The rigging was different on the old OMC vs the outboard. Will need to run the cable through the other side of the box.

All in all I'm happy so far, got a few bugs to work out but that's why we test lol. Plus it was a beautiful day on the lake in northern Illinois for mid November.
View attachment 20231115_145300.mp4

 

[Scott06]

Got the boat on the water yesterday, the motor stayed on and she might sit slightly lower in the rear than it used to but seems ok. I got very little propulsion though at different trim levels and RPM. Talked to a local propeller shop and they said that the 15 pitch should be good but it may not have enough cup in the blades. Dropping the prop off to them today.

Also found that the steering was reversed didn't think about that. The rigging was different on the old OMC vs the outboard. Will need to run the cable through the other side of the box.

All in all I'm happy so far, got a few bugs to work out but that's why we test lol. Plus it was a beautiful day on the lake in northern Illinois for mid November.
View attachment 391902

Thats a good start although the steering must be weird with L/R reversed....

When you say you had very little propulsion - what do you mean? Did rpms climb with no forward momentum /prop splipping?

Or did rpms not go up?

Would also check the motor height if too low can cause too much drag. On my brothers Twin Vee power cat we had to raise the engine about 2" to get the cav plate where it should be underway

 

[stan2076]

Thats a good start although the steering must be weird with L/R reversed....

When you say you had very little propulsion - what do you mean? Did rpms climb with no forward momentum /prop splipping?

Or did rpms not go up?

Would also check the motor height if too low can cause too much drag. On my brothers Twin Vee power cat we had to raise the engine about 2" to get the cav plate where it should be underway

Yes the steering was very confusing to say the least lol

I had the motor up to almost 6k and there was little to no forward motion. At lower RPM's the boat topped off at around 5mph, but as you increased the RPM's you could feel the prop doing less and less.

 

[Scott Danforth]

flip the helm on the steering

check the hub on the prop

 

[stan2076]

flip the helm on the steering

check the hub on the prop

It's funny, the original prop was chewed up so I picked up the same 15.25x15 used but clean Honda OEM prop off eBay. I checked it this morning and someone had clearly stamped the prop and the hub. The marks were aligned but I'm thinking why would someone do that if they were not checking for hub spin? The original OEM prop has no stampings and it's clear that someone used a punch or something similar to mark the one from eBay. It does really seem to act like the hub is spun. The person at the prop shop did say that a prop without enough cup can have similar symptoms as a spun hub as well. I'll let them check it out.

I wish I had thought to bring the old beat up prop and swapped it in while I was on the water yesterday. Would have given me a little more info.

 

[stan2076]

Tried out the prop after cupping was added. Huge difference, was able to get up to and stay at 20 mph. Hole shot is poor yet, had to slowly bring up the RPM's to get it to 20. At wide open throttle it was at 5500 rpm, redline is 6000 so there is some room to play with. Prop guy said to let him know the results and he can make additional adjustments.

When I installed the shift and throttle cables I ran the ends all the way down so there may be some more throttle because the cable is at its shortest length? Also need to adjust the shift cable, shifting into gear is not as smooth as it could be.

That's all the testing for this year, cover is going on, will be finishing up interior seating over old engine bay etc before next season. All in all pretty successful I would say, a little over a month from a 1975 OMC I/O to a 2017 Honda outboard. Cutting and welding aluminum is as far as I want to go in boat work, God bless you guys laying down fiberglass!

 

[Scott Danforth]

Pics or it didn't happen

 

[stan2076]

Video from today, at 39 degrees lol
View attachment 20231118_095428.mp4

 

[Scott06]

Tried out the prop after cupping was added. Huge difference, was able to get up to and stay at 20 mph. Hole shot is poor yet, had to slowly bring up the RPM's to get it to 20. At wide open throttle it was at 5500 rpm, redline is 6000 so there is some room to play with. Prop guy said to let him know the results and he can make additional adjustments.

When I installed the shift and throttle cables I ran the ends all the way down so there may be some more throttle because the cable is at its shortest length? Also need to adjust the shift cable, shifting into gear is not as smooth as it could be.

That's all the testing for this year, cover is going on, will be finishing up interior seating over old engine bay etc before next season. All in all pretty successful I would say, a little over a month from a 1975 OMC I/O to a 2017 Honda outboard. Cutting and welding aluminum is as far as I want to go in boat work, God bless you guys laying down fiberglass!

Would think based on what rpm you give , if prop guy can repitch down 2” you should be there at wot rpm and improve holeshot. Adding cup drops wot rpm similar to adding pitch …

 

[stan2076]

Would think based on what rpm you give , if prop guy can repitch down 2” you should be there at wot rpm and improve holeshot. Adding cup drops wot rpm similar to adding pitch …

Thanks I'll be going back to him for more adjustment.

This is a 24 foot pontoon, I know there's a lot of variables but is 20 about right for top end with the 115? It's about 5 MPH faster than the OMC120 right now. Hoping to squeeze a little more out of it.

 

[Scott Danforth]

FWIW, my buds boat does 18mph with a 30hp.

I would think with the correct height and correct prop you should be closer to 30

 

[stan2076]

FWIW, my buds boat does 18mph with a 30hp.

I would think with the correct height and correct prop you should be closer to 30

Thanks, prop place was closed today, I'll talk to them tomorrow.

 

[stan2076]

Working on getting the boat ready for the season. When last tested in fall was able to get the boat up to 20mph but from standstill had to really feather the throttle and slowly get it up to speed before it could grab some water. If I punched it it would just sit there. I'm wondering if the prop is too high. Attached photo shows approximate midline of pontoons in relation to prop. Most other pontoons I see the prop seems to be lower. I'm at the lowest setting now so I would need to get a jack plate to lower it. If the prop is too high it's going to cavitate I would assume?