snowmobile engine marine convert?

[racing fan]

i want to make a small outboard motor but i want to use a 500cc 2 stroke air cooled snow mobile engine where do i get a short shaft mid section and lower unit that could take super high rpm (6000-7500) and will have F,N,R and shift well but not cost much (where do i find a used one)

[Erich_870]

eBay?! Call your local power sport place and see if they have any sleds someone wanted to get rid of?

Erich

[racing fan]

well i got the motor but i need a mid section that can handle the power about 30-40hp and some 8000 rpm and not shake out of control and or twist into a Christmas ornament with the torque would like a old 70-80's mid and lower unit off of a mercury short shaft motor 30hp work??????

[Erich_870]

Sorry, I missed that you had the engine already.

I've never looked closely at a snowmobile engine. Is it a horizontal or vertical shaft output?

Erich

[racing fan]

all snow mobile engine are horizontal but there is no reason a 2 stroke cannot run on its side there is no oil in in the bottom like a 4 stroke so if i flip the cab by means of a machined plate in between it it will run fine but

where do i get a short shaft mid and lower unit for it that's in good condition???

people have flipped 2 stroke before why not now

[racing fan]

i found a cheap short shat motor and lower unit a 15 hp Sea King by US Marine but would i cause damage by bolting on double or more hp
because a 5hp-10hp outboard have the same shafts what about a 15 hp and a 30hp??????

[Erich_870]

I figured it was a horizontal.

It sounds like you're set on marrying it up to an outboard lower end, but I'd turn it into a belt driven short tail if it were mine. Just saying...

Hopefully someone will chime in with the info you're looking for.

Erich

[racing fan]

well yea i am set on it but if i get that piece o crap 15hp motor and replace the power head

would i damage the mid and lower by doubling the hp and load and would it stay in gear well ??????

[racing fan]

would i damage the mid if i put that snowmobile motor on it

[pistnbroke]

lots of parts for outboards on e bay ..some without powerheads .....the trick of mounting a motor to a lower leg is to weld the end of the crankshaft from the original engine to the new engine ..then it mates together .....dont think the rpm is a problem as many outboards run 6000 rpm + Get a leg from a 40-50 hp ...as you may not get a suitable prop for a smaller leg to match your power output ..why not try an outboard wrecker...

[Frosty]

Originally Posted by racing fan

all snow mobile engine are horizontal but there is no reason a 2 stroke cannot run on its side there is no oil in in the bottom like a 4 stroke so if i flip the cab by means of a machined plate in between it it will run fine but

where do i get a short shaft mid and lower unit for it that's in good condition???

people have flipped 2 stroke before why not now

Woah do you like working in the workshop? if you do Ok but just go get an outboard.

It seems you know little of outboards worrying about 40HP did you know they come in 300HP flavour.

Cooling, carbs ,cable control , gear selection. And then some --you will be disappointed.

[pistnbroke]

If you look at other racingfan post you will see that is what he is a fan...no photos of products produced after 75 posts...like you say time is money and when its finished it will be worth nothing....but people enjoy themselves in different ways..so who are we to critcise.... not costing me or you a bean Frosty ....

[racing fan]

well i haven't made all them yet i only have so much money so some i did research on and will save for later in like a year or so

i know outboard come in many sizes and the new V8 outboard 4 stroke is over 500hp it will come out soon its by some small co.

but all i want to know if this crappy 15hp short shaft 2 stroke outboard mid and lower unit will take 30-40hp and high rpm with out turning into a twisted art sculpture????????

i research all my projects then do them when i got the money

is it such a problem to do research and ask help from fellow boaters so i don't waste my time and money

and i do love to work in the garage on motors and stuff its great fun

[pistnbroke]

you ,missed the point ..you wont get a prop with sufficient diameter and pitch on the 15 hp to absorb all the power from a 40 HP ....forget the high revs stuff 40 hp is still 40 hp ....and if it runs faster you will need less pitch than a 40 HP doing 5000 rpm over about 2500 rpm the prop can get very inefficient ...

[racing fan]

wow i dint think of that yea your right to balance out the rpm and torque the cavation plate is too close to the shaft so that would be a problem i guess I will look for a blown up 30-35hp short shaft one that should work gosh this is becoming more and more money i guess what I heard was right

ha here is what i heard

boat means:
b-bust
o-out
a-another
t-thousand