Long Shaft Motor on Short Shaft Boat Idea's?

[gazza2006au]

Hey Guys i picked up a little tinny yesterday to get me though untill my bigger boat is welded and new trailer built i don't want to miss summer and haven't seen the water in over 6 months!

Does anyone have a idea on how to jack up a long shaft outboard on a short shaft transom? i need a good idea that won't see the motor becoming part of a reef and us rowing against the wind ;)

I have a 90's model Savage tinny rated to 20hp SS i have on hand a old vintage 74 model 25hp LS i would like to run on the boat

[Triple]

How many inches does it need to come up and how much do you want to spend? How far off is it if lifted as far up as it can go? Is the boat temporary? Jack plate, is an option but cost a few hundred.

[Noelm]

You need to raise it 5" now, whether you just raise it as high and you can and just put up with it, remodel the transom, or make some sort of adapter is up to you.

[gazza2006au]

Yeah that is the worry the old vintage Evinrude and Johnsons LS were 22.5" i have 15" transom 7.5" is a bit of a hike up, i do have some scrap 50x50x3mm aluminum box section not really sure how strong it will be,

I'll try jerry rig something up

There is a poly mount on Ebay which converts a tinny from SS to LS but its only rated to 15hp max

[gazza2006au]

I actually tore into one of the gearboxes i have on a couple motors i picked up for my other boat,i purchased one working Johnson 25hp long shaft and it came with a free Johnson 25hp short shaft, i was wondering what was going on with the SS gearbox seems its missing the shift lever does anyone know where i can pick one up from? i tried Gumtree and Ebay no good, found one bloke on gumtree that wanted $440 for a vintage 1974 model gearbox which is crazy priced

the shift lever connects to the gear selector shaft and a fork goes over the clutch dog to engage gears

looks like the gearbox was either drained or it dripped out over time in storage

[Gon Fishun]

Yeah that is the worry the old vintage Evinrude and Johnsons LS were 22.5" i have 15" transom 7.5" is a bit of a hike up, i do have some scrap 50x50x3mm aluminum box section not really sure how strong it will be,

I'll try jerry rig something up

There is a poly mount on Ebay which converts a tinny from SS to LS but its only rated to 15hp max


You would have to weld the box section on. Bolting it will allow it to flex to much.

[GBC]

The poly one from Solas would carry a '74 model 25 no problem. http://uploads.tapatalk-cdn.com/20161206/41f9d8afe7e312810e516c364401a678.jpg


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[gazza2006au]

The poly one from Solas would carry a '74 model 25 no problem. http://uploads.tapatalk-cdn.com/20161206/41f9d8afe7e312810e516c364401a678.jpg


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i think they are only rated to 15hp

[GBC]

Yes I understand that, I own one - they are laminated and bolted poly - you will tear out the transom before you break the adapter. In '74 motors were shaft rated not prop rated too and they ran on leaded fuel and didn't have 42 year old carbs. If his develops much more than a current day 15 I'd be amazed. It will undoubtedly do the job if the transom is up for the extra leverage.

[Noelm]

Bit hard to see how it works, but does the motor just bolt to that poly block?

[GBC]

The block bolts to the stern and the motor clamps to the block which is rebated for safety. It's a riser basically. Does nothing more or less than welding in an ally riser except that it is removeable.


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[Triple]

Couple of bits of heavy alloy C channel as a fixed jack plate will do the job.

Google fixed jack plates for ideas.

[gazza2006au]

Couple of bits of heavy alloy C channel as a fixed jack plate will do the job.

Google fixed jack plates for ideas.
Now that is a cheap idea!!

[Spaniard_King]

I actually tore into one of the gearboxes i have on a couple motors i picked up for my other boat,i purchased one working Johnson 25hp long shaft and it came with a free Johnson 25hp short shaft, i was wondering what was going on with the SS gearbox seems its missing the shift lever does anyone know where i can pick one up from? i tried Gumtree and Ebay no good, found one bloke on gumtree that wanted $440 for a vintage 1974 model gearbox which is crazy priced

the shift lever connects to the gear selector shaft and a fork goes over the clutch dog to engage gears

looks like the gearbox was either drained or it dripped out over time in storage

no wonder it was free, that one is destined for the bin!!!

[gazza2006au]

Couple of bits of heavy alloy C channel as a fixed jack plate will do the job.

Google fixed jack plates for ideas.

I just finished a job i had to remove the keel and weld on a new keel from 50x50x6mm angle aluminium i am left with around 2.5 meters so after googling pictures it looks like i will be able to use this left over aluminium for the jacking plate bloody brilliant i may just make it out on the weekend for a fish ;D

[gazza2006au]

no wonder it was free, that one is destined for the bin!!!

Lol yeah the motor was just a spare to use the tiller handle on the other motor of the 2 motor deal, but since buying a second tinny and it being short shaft i was thinking of repairing this short shaft motor

there is no pitting to the gear that i could see its just surface rust from atmosphere air entering the gearbox on hot/cold days, if i was going to fix it i would soda blast it than give it a good look over, their is no rust on any of the needle bearing

but that fork shifter or shifter arm is NLA so the gearbox is good for parts or rendered useless

however if the other good motor fall's off and into the drink than its only a $200 motor haha ;D

[gazza2006au]

Got it sorted guys

[up the creek]

if ya aint fixed it yet gazza, i was talkin to brisbane yamaha today they got a guy who professionaly welds your tinnie for about $160 i dont know if your in brissie, its stronger i believe to get it welded and cheaper with this guy if your not in brissie ask around your local dealers surely they have some1 they use

[tunaticer]

If you are going to stick with that design patch up job be sure you only bolts the motor onto the touching flange, do not use the screw bolts normally used. The force applied whilst underway will collapse the channel you intend to tighten to.
Failing that send mt the gps mark for the new arti patch.

[gazza2006au]

I took the tinny out in the bay about a week ago with the jacking plate and i could barely steer the amount of prop torque was incredible i actually needed both hands to steer the boat, i ended up removing the jacking plate and getting out the welder to weld the holes i than removed the long shaft extension from this motor and i had a spare 35hp short shaft i used for spares to convert this one

it's now short shaft and drives like a dream, steering is very easy while underway, top speed is scary fast especially into the wind as it wants to turn the nose left or right ata heart beat but around 70% throttle she drives beautiful