Motor, props, and cavitation

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narfi
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Re: Motor, props, and cavitation

Post by narfi »

I know nothing about that kind of setup, but it looks like the geometry would allow the bracket to lower quite a bit further down than the picture shows in the down position. I would think it could go down as far as it can go up........

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Jaysen
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Re: Motor, props, and cavitation

Post by Jaysen »

Mercury says no. Especially with the lumps we will be in. There is some type of transport lock to allow tilt lock up but I have t checked on availability.
My already completed 'Lil Bit'. A Martens Goosen V12 set up to sail me to the fishing holes.
Currently working on making a Helms 24 our coastal cruiser.
“Mark Twain/Samuel Clemens” wrote:Eat a live frog first thing in the morning and nothing worse will happen to you the rest of the day.
Jaysen wrote: Mon Apr 29, 2019 3:44 pm I tried to say something but God thought I was wrong and filled my mouth with saltwater. I kept my pie hole shut after that.

cracked_ribs
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Re: Motor, props, and cavitation

Post by cracked_ribs »

Kind of funny there isn't a useable travel lock on it. I have the next generation of the same motor, and lock it halfway horizontal on a planing boat, in rough water. If I had to guess I'd say it's withstood maybe 500 hours of rough water planing like that. The treatment yours gets wouldn't be anything near as harsh.

But I'm not familiar with that model. I'm surprised if the travel lock position won't withstand the sailboat experience, though.
I designed my own boat. This is the build thread:

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fallguy1000
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Re: Motor, props, and cavitation

Post by fallguy1000 »

I wouldn't jerry rig it.

A lower pitch would give you more low end control, but it won't matter if the prop is blowin bubbles.

Important to know what the used motor was on before.

Most likely, you'll want to pitch down. And get down.

You should be able to see with the engine off and in gear what is making it loose. Something could be worn or the lock might only be grabbing on one hook. Probably a bit tricky to do it on the boat.
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fallguy1000
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Re: Motor, props, and cavitation

Post by fallguy1000 »

It looks to me like you can lower the motor on the bracket. I'd try it for now even if you have to bungee it out of the salt water when away.

No?
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TomW1
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Re: Motor, props, and cavitation

Post by TomW1 »

Jaysen I keep looking at your bracket and thinking more and more. Try moving the pin on the bracket from where it is near the motor to hole near the boat. I think that will let you will allow you to lower it further. I have not worked a lot with these brackets just a couple and they are all different. Just something to try.

Tom
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Jaysen
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Re: Motor, props, and cavitation

Post by Jaysen »

TomW1 wrote: Mon Apr 26, 2021 2:24 am Jaysen I keep looking at your bracket and thinking more and more. Try moving the pin on the bracket from where it is near the motor to hole near the boat. I think that will let you will allow you to lower it further. I have not worked a lot with these brackets just a couple and they are all different. Just something to try.

Tom
Here is the motor full down.
8399

If you look at the section in question it does look like it might allow a little extra movement.
8398

Problem is that the position lock device is captured middle of the bolt. Since that is already extend to the lowest position, moving that bolt just tilts the transom.
8397

I’ve looked at several similar plates and the manuals all show the above to be correct.

I measured the motor drop and it is only 11”. I have found lifters with 15”+ of travel. I believe that I will be acquiring one of those once I’ve checked all the couch cushions for loose change.
My already completed 'Lil Bit'. A Martens Goosen V12 set up to sail me to the fishing holes.
Currently working on making a Helms 24 our coastal cruiser.
“Mark Twain/Samuel Clemens” wrote:Eat a live frog first thing in the morning and nothing worse will happen to you the rest of the day.
Jaysen wrote: Mon Apr 29, 2019 3:44 pm I tried to say something but God thought I was wrong and filled my mouth with saltwater. I kept my pie hole shut after that.

cracked_ribs
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Re: Motor, props, and cavitation

Post by cracked_ribs »

And there's definitely no locking tab to keep it up for travel?

Image

That's on a 9.9 that's a generation later; I keep it in the travel position (as absolutely everyone here does on their kickers, which are on every boat) because it's got a 25" leg and would drag otherwise.

I apologize for hammering on this point, I'm just so surprised to see a kicker without that option. I couldn't possibly guess at the number of kickers I've seen resting on their travel lock, from the little 9.5 1970 Johnson we had when I was young, to the 2012 (I think) merc on my current boat.
I designed my own boat. This is the build thread:

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Re: Motor, props, and cavitation

Post by Jaysen »

The manual clearly states the lock that is there is NOT a travel lock. It indicates that a travel lock is available but didn’t provide a findable part number for that lock.
My already completed 'Lil Bit'. A Martens Goosen V12 set up to sail me to the fishing holes.
Currently working on making a Helms 24 our coastal cruiser.
“Mark Twain/Samuel Clemens” wrote:Eat a live frog first thing in the morning and nothing worse will happen to you the rest of the day.
Jaysen wrote: Mon Apr 29, 2019 3:44 pm I tried to say something but God thought I was wrong and filled my mouth with saltwater. I kept my pie hole shut after that.

cracked_ribs
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Re: Motor, props, and cavitation

Post by cracked_ribs »

That's extremely strange, and all I can tell you is that I have probably seen a thousand kickers riding on that large bearing surface.

We used to run my 20 footer in steep 3' seas on plane on that thing. That's just what is done here. Everyone runs a kicker because we slow troll, and everyone just tilts up the motor and rests it on the lock. I doubt I know a single person who does otherwise.

A sailboat is cake for that application; you're never going to be airborne. I've had kicker brackets pop loose at speed, but never had an issue with the tilt lock.

You're not supposed to TRAILER it on the tilt lock (everyone does but you're not supposed to) but if you're not supposed to boat with it like that... what's it for? Why such a sturdy bearing surface?

I'd be tilting it up, lowering the bracket on the hull, and running it.
I designed my own boat. This is the build thread:

viewtopic.php?f=12&t=65349

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