60HP 2-stroke Boat outboard engine clutch option?

[rodney007]

Is that motor running premix?

And if I may make a suggestion, you should add some support to the bottom of the block where it originally mounted. The block is likely to Crack from the stress with the mount where it is currently

The flange I am having made will be secured to the mount I have tacked togeather.

Yup on pre-mix

 

[Toycrusher]

That should take care of it. The cast aluminum cases are fairly brittle so tying to the flange should take care of that weakness

 

[rodney007]

Yes indeed. One mount point i was going to use alredy failed on me. The flange point is very strong and the thread holes are deep and solid. There aint really many places to mount the engine correctly from.

 

[Desertduler]

I am going to with trying a Noram - enforcer with heavy duty springs (1inch bore).

I also did like the look of the Duster 94c but will require a jack-shaft and more mucking around - should the enforcer not work so well then I will go down this route.

I think it will be a good experiment so others doing similar HP conversions will know where the cut-off point should be. The supplier seems confident that the enforcer should do the job for what I am wanting but we will have to see.

I have an engineer that will turn a new axle with 1" key'd od to 18mm splined reduction for strength (rather than increase the size of the factory 18mm shaft).

Currently sorting payment now with the supplier but shouldn't take too long to get here.

I use a Noram Enforcer clutch on my 277 Rotax powered kart and it has been bulletproof, I can't wait to see you complete this build it will be different for sure and I am happy to see someone use a engine that is not the same old boring cookie cutter power plant! Dare to be different!

 

[rushking19]

Yeah I can't wait to hear it I found a video on YouTube of and a go Kart with outboard motor
https://m.youtube.com/watch?v=LSQ3bE0AfBQ

 

[rodney007]

Sorry it took a while for an update as I was waiting on my flanges to be cut.

The main flange is done with the water inlet and outlet ports (for the radiator) and the two exhaust ports. I was worried my measurements would be off but everything worked out great.

Enforcer clutch also arrived, The carb flanges are also done to turn the carbs upright 90 degrees (these are just sitting under the carbs in the pic).

I will change from mechanical fuel pump to electric as I already broke it (old plastic).

 

[rushking19]

Looking good

 

[Toycrusher]

That's a massive base plate, good job!!!

 

[Desertduler]

Excellent! Keep up the good work!

 

[Toycrusher]

What rpm is that clutch set to engage at? Those little outboards don't start making big power till about 4000 rpm

 

[Desertduler]

What rpm is that clutch set to engage at? Those little outboards don't start making big power till about 4000 rpm

No worries for him, I use a Enforcer clutch on a highly modified 277 Rotax two stroke engine that engages at 2500 rpm and the engine pulls over 7500 rpm, you most certainly do not want the engine to rev up to 4000 rpm and then have the clutch shoes engage that will smoke the clutch, his engine will have plenty enough power to move his kart at a low clutch engagement providing his gear ratio is not too high, been there done that and still doing it. You may be thinking about the engagement rpm of a CVT which indeed you would want to have the engine rpm engagement higher to a degree.
Plus his engine is reed valved inducted with two cylinders it will have plenty of low end torque to move at a low rpm engagement unlike a peaky soggy bottom end piston port inducted engine.

 

[rodney007]

nice vids, how much HP do you think the 277 is putting out?

 

[Desertduler]

nice vids, how much HP do you think the 277 is putting out?

Thanks man! I would guess maybe 35-38, a bunch more than the stock 26 that the engine is rated at, I will build a new pipe for the engine as I have added the reed valve and rear boost port and calculate the new configuration in the new pipe design and squeeze some more out of the 277, fun stuff, you have my attention with your engine and I will follow your thread! I am refreshed to see someone have the ballz and guts to be different! Keep on going and pay no attention to any nay sayers because I know for sure that your boat motor will work and be awesome when you complete this build.

 

[rodney007]

Thanks man! I would guess maybe 35-38, a bunch more than the stock 26 that the engine is rated at, I will build a new pipe for the engine as I have added the reed valve and rear boost port and calculate the new configuration in the new pipe design and squeeze some more out of the 277, fun stuff, you have my attention with your engine and I will follow your thread! I am refreshed to see someone have the ballz and guts to be different! Keep on going and pay no attention to any nay sayers because I know for sure that your boat motor will work and be awesome when you complete this build.

Hehe, cheers for the vote of confidence! "no pressure"

I could see your kart haulin some arse in vids and knew it must have quite a few HP's - Do you get any slip so far on the enforcer? how have the clutch pads held up and do you have the purple springs installed?

 

[Kartorbust]

I'm curious to know how your going to balance this kart out. Engine itself ways without the lower unit (where the prop sits) weighs close to 75kg or about 150lbs whole engine with everything is 109kg or 240lbs. Max RPM is 5000-5500. Going to have a serious amount of weight on that kart. Not to be a downer but just curious to know what your plan was to balance it out with that much engine.

 

[Desertduler]

Hehe, cheers for the vote of confidence! "no pressure"

I could see your kart haulin some arse in vids and knew it must have quite a few HP's - Do you get any slip so far on the enforcer? how have the clutch pads held up and do you have the purple springs installed?

Here are some photos of the clutch shoes after a season of torture,the Enforcer has been bullet proof, you can see indeed that I have the 2500 RPM engagement purple springs installed in the clutch,after the clutch engages is does not slip,the videos do not give any real justice to the pull that the modified Rotax has, the first time I let some people drive that red pig it scares the sh1t out of them most certainly on asphalt where the rear tires hook up better.

 

[Toycrusher]

I'm curious to know how your going to balance this kart out. Engine itself ways without the lower unit (where the prop sits) weighs close to 75kg or about 150lbs whole engine with everything is 109kg or 240lbs. Max RPM is 5000-5500. Going to have a serious amount of weight on that kart. Not to be a downer but just curious to know what your plan was to balance it out with that much engine.

It certainly weighs more than a 6.5 motor but not quite that bad. The dressed powerhead shouldn't be much more than 75 lbs. I haven't had one off in a while but the larger 3 cylinder blocks are still under 100 lbs

---------- Post added at 06:07 AM ---------- Previous post was at 06:04 AM ----------

These two strokes are sensitive to exhaust back pressure. Some outboards have dual exhaust, long tube for bottom end torque and then a valve that opens to essentially a short dump for high rpm power. If your able to, a dual exhaust with valve may benefit you

 

[rodney007]

I'm curious to know how your going to balance this kart out. Engine itself ways without the lower unit (where the prop sits) weighs close to 75kg or about 150lbs whole engine with everything is 109kg or 240lbs. Max RPM is 5000-5500. Going to have a serious amount of weight on that kart. Not to be a downer but just curious to know what your plan was to balance it out with that much engine.

Not sure which engine you are weighing but its not mine. It is significantly less weight than a motorbike engine (twin+gearbox) and at least half of your figure of 109kgs.

My plan to balance it at this stage is to move the already off-set mount drivers seat over a few more inches to the left.

Then once* I know this engine will work correctly I will make my own frame/chassis from scratch.

These two strokes are sensitive to exhaust back pressure. Some outboards have dual exhaust, long tube for bottom end torque and then a valve that opens to essentially a short dump for high rpm power. If your able to, a dual exhaust with valve may benefit you

In regards to the exhaust. From factory the engines 2-ports merge into one and it then is a straight pipe down to the prop. I have been told that the pressure from the water creates the sonic vacuum to aid the combustion process similar to that of what an expansion pipe would do.

I don't think I will be mucking about with valves etc at this stage...

In this case I will likely just run two expansion pipes cut from a motorbikes exhaust, sure it wont be perfect but will hopefully will be better than not running anything.

 

[Desertduler]

Rodney, may I ask what the displacement of your engine is?

 

[rodney007]

At least 600cc but I don't know for sure - Its a nightmare trying to identify an old mariner :-(