150cc Scooter Engine Winch, can't deep water start.

So we have built a winch from a 150cc scooter engine (157qmj) which was taken from chinese scooter. From information that I've found in internet these kind of engines have at least 7.5 hp, so I figured out that this will be enough to make deep water starts, as a lot of people here use 6.5hp engines with TAV and they can. So we've already spent a lot of time trying to make this thing do deep water starts: decreased spool diameter to minimum possible, replaced piston rings, checked valves of the engine, took half of weights in CVT out, so that it would engage at higher RPMs and still it can not deep water start. Anyone can give any tips? )

(this is also weird because there two more threads here where people used scooter engines of 50cc and 100cc and both could do deep water starts)

give some more info about your gear ratio and spool size so that we all know what we are talking about.
it's pretty hard to make a suggestion without that info.

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	vincentmdr wrote:
	give some more info about your gear ratio and spool size so that we all know what we are talking about. it's pretty hard to make a suggestion without that info.

It has stock gears and CVT, so I believe gear ratio is 13 to 40 teeth and also I found out, but I am not sure about that, CVT of this engine when it doesn't expand gives a gear ratio of 1:11. Spool is 48cm outer diameter and around 26 cm inner diamter, width is 12 cm.

I don't really know scooter engines but the gear ratio that is most common (use at almost every winch out there) is 1:6 instead of your 1:11.... and that 13 to 40 teeth is a 1:3 ratio. so not really sure what you mean here..
also, a 26cm inner diameter is way to big in my eyes.. I believe mine is 15cm.. I've heard of people only having 10cm..

hope you can use this information to your advantage!

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it sounds like your understanding of the gearing may be backwards, increase your spool sprocket for more torque but you'll sacrifice top-end speed

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	vincentmdr wrote:
	I don't really know scooter engines but the gear ratio that is most common (use at almost every winch out there) is 1:6 instead of your 1:11.... and that 13 to 40 teeth is a 1:3 ratio. so not really sure what you mean here.. also, a 26cm inner diameter is way to big in my eyes.. I believe mine is 15cm.. I've heard of people only having 10cm.. hope you can use this information to your advantage!

yes, I know about spool diameter, but we can not make it smaller because there is no space. Scooter engine has a CVT connected to the crankshaft, then CVT goes to transmission where there are two gears, one on the wheel shaft and on CVT shaft, so it is almost the same as you use an engine with TAV and sprockets. As I know TAV works the same as CVT, and CVT has its own gearing ratio; on a scooter engine it is 1:11. The gears in transmission have a 1:3 ratio (13 to 40 teeth). So as I understand this ratio isn't best for winch and a 1:6 ratio is what it should be. I tried to find aftermarket gears in our city and as it turned out there are none Smile

. May be more engine tech tips, on how to check if the engine is correctly adjusted etc.? Smile

And also what is approximate speed when deep water starting when the winch pulls out rider so that it is possible to stand up? (just trying to figure out at what moment the engine should be at max hp and torque) and when you stand up and actually surf is the winch engine less loaded?

I think that it would be easier for me and others to help you with the problem if you post some pictures of your winch, detailing your clutch and gearing.
at the moment, I think your biggest issues are that your spool diameter is TOO big and your gearing is wrong. you should really get that sorted out.

There is no exact speed that you need to have for deep water starting. just an amout of torque. being able to deep water start is also dependable of the weight of the rider and the board used. wakeboard or wakeskate can make a big difference! Also, the skills of the rider also are important. I am about 230LBS and I can deep water start with a wakeskate behind my winch. I have friens who weig like 180-200LBS and they can't start on a wakeboard.
and yes, when you stand up and actually surf than the engine is less loaded and therefore will gain in RPM.

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I love my winch !!

Thanks a lot for tips and advices.
Pictures I will be able to post after weekends. Winch has a centrifugal clutch which engages at around 2500-3000 rpms. Unfortunately we won't be able to make spool with a smaller inner diameter because there is just not enough space because it is a scooter engine and spool is connected to the shaft where the wheel should be. Smile

So I will try to do something with CVT, may be use a bit longer belt or spacers to change gear ratio.

The engine pulls really strong, just at some point it stops increasing speed. We will try jump starts and starting from the shore also, may be it is just us, that "don't work good" and not the winch Smile

BTW, we use wakeboard 138, and we weigh around 170-180 LBS