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9HP motor -- WTF - can't possibly be underpowered - can it?

 
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robsmaze
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PostPosted: Aug 16, 2009 12:48 am    Post subject: 9HP motor -- WTF - can't possibly be underpowered - can it? Reply with quote

Okay - so i have a 9HP motor honda GX270 on my winch (8" spool, 1000' amsteel.) When i first built the winch it was a little underpowered for my bigger friends (200+ pounds) with a 60 tooth sprocket, but for me and everyone else under 180 it was fine, we could even use a 58 tooth sprocket (I have the 12 tooth TAV2) and deep water start all day long. but I'm a nice guy so i started messing around with the motor and the gearing. First I put a bigger carb on (GX 340 carb - supposed 3 HP gain on the top end.) not enough... Then a #102 carb jet per nr-racing's reccomendations. Then a really nice K&N type air filter. still not enough... Then i removed the governor and put a 66 tooth sprocket on there. I still can't get these guys up! Do they just suck? I would think a 9HP motor should tear their arms out!!! But it seems like its not even deep water starting me that well anymore. Is my motor just whacked out? The only thing that might cause problems is my handcut spool (plasma cutter and 1/8" steel plate) is a little out of true. Does anyone have any ideas? I've been messing with this all summer and I still can't get my two friends out of the water. I'm at wit's end. Give me some ideas - OK?
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TWG
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PostPosted: Aug 16, 2009 8:16 am    Post subject: Reply with quote

your friends suck!!! that k&n is probably sucking in too much air also id go back to the stock filter. unless when you re jetted the carb it called for that air filter.

do you have to deep water start?
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GnarShredd
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PostPosted: Aug 16, 2009 8:46 am    Post subject: Reply with quote

You really shouldn't have a problem with the setup you have. I'm about 215lbs and have an 8hp engine and it can deep-water start me on a wakeskate fine with plenty of power.

What happens when you try to pull them up? Do they just drag through the water and never quite plane out? If so, does the engine bog down a lot? Yours might just be a tad bit slow (you can make some small adjustments to the throttle lever and that should help if that's the case)
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robsmaze
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PostPosted: Aug 16, 2009 12:33 pm    Post subject: Reply with quote

yeah, they just drag through the water. it's like they can't get the top edge of the wakeskate out of the water to start planing. but they get up fine behind the boat! the throttle lever is set straight to the throttle piece on the carb (governor is removed so no use using the stock throttle accessories.) so there are no adjustments to make on the throttle.

i'll try putting the old air filter back on, but i did put a bigger fuel jet in the carb (from #92 to 102) per what this guy at a go-kart racing place told me to do. I haven't tried that yet - it may make all the difference. and yes, we have a few places where deep water starts are the only thing you can do. i'm really fond of the shallow water start (i.e. sitting on your but in a foot of water and dragging for a few feet and then popping up) but some of the spots we go are super rocky by the shore.

its nice to know that with an 8HP, people who are 215 can deep water start fine. maybe my motor just needs a tune-up. valve adjustments might be a little off or something.

anyone have any more ideas?

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TWG
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PostPosted: Aug 16, 2009 1:10 pm    Post subject: Reply with quote

new plug?
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sandiego4real
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PostPosted: Aug 17, 2009 1:10 pm    Post subject: Reply with quote

robsmaze, My 6.5 deep water starts my friend that is 215 pounds, I think you have seen us do it at fiesta island. I found out its all about the rider mostly, he has to know how to get up behind the winch and get on plane. How heavy are these guys because you deep water started him one time behind your winch pulled him right up!
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burn
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PostPosted: Aug 17, 2009 2:22 pm    Post subject: Reply with quote

put a turbo on that beach. Laughing

and yea your friends suck, i am a little over two hundo and i get every time on a 6.5 hp motor. try the sit down method on your friends, it might not be able to deep water start them.

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robsmaze
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PostPosted: Aug 17, 2009 8:43 pm    Post subject: Reply with quote

yeah jake - i've totally seen you do it. and he can get up some of the time. i don't know, i checked the plug - its fine, so maybe once i try it with the new jet in the carb it'll be fine. it could be that i've just messed around with the engine so much its getting all screwed up...
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sandiego4real
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PostPosted: Aug 17, 2009 10:31 pm    Post subject: Reply with quote

That is true, hope you get it dialed in man.
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wakeshredder
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PostPosted: Aug 24, 2009 9:35 pm    Post subject: Reply with quote

I am having very similar issues. I have a 7hp b&s with 12 tooth TAV and 60 tooth spool sprocket. The spool has an inner diameter of 8". I have 600' of dyeema rope on the spool. My lighter friend get up quick, but anyone in the 200+ range drags. I weigh close to that and I drag while the engine struggles and eventually I will get up. Unfortunately, our winch spots are limited and often the pull is 100-200 foot. I don't want to drag half my pull. I own a moped that has a variator and you can change the weights and springs on the transmission to make it snap into higher gears quicker. Does anyone know if there are weight/spring kits for the TAV?
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wakeshredder
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PostPosted: Aug 26, 2009 8:54 am    Post subject: Reply with quote

robsmaze, Have you adjusted the spring tension on the TAV2? What color is the spring. I just found out about tension adjustment. If you up it to position 3, It should increase the amount of time before it shifts into it's highest gear. Thus, allowing the engine to get up to peak rpm and not bog it down on the heavier people. It should be plenty to allow a smooth start. I stumbled upon an article about go-karting when I realized that there is an obvious adjustment that can be made...

SETTING SPRING PRELOAD:


Instructions on disassembly & reassembly of a symmetrical & asymmetrical torque converter system. (20 , 30 &40 Series)

Remove the driven unit from the machine and lay it flat on a work area.

DISASSEMBLE:

1) With the spring facing up, remove the retaining ring from the end of the post (Caution: this spring should be under pressure)

2) Lift up the fixed cam (the one with the three holes and spring), 40 series only one

3) Inspect the insert buttons, (one on each side of the moveable cam)
If worn or missing, replace all 6 buttons, 40 series only 3 Use a pair of pliers to remove any remaining buttons and press in new ones.

REASSEMBLE:

1) Insert the spring tang in the number one, two, or three hole of the fixed cam, place the spring and cam down over the post of the fixed post and only push the fixed cam down about ¼” at this time. (Do not push it down all the way)

2) Rotate the movable face (the part that contains the buttons) 120 degrees, 1/3 of a turn counter clockwise if it has a blue or red spring, clockwise if it has a green spring.

3) Once rotated, hold in the moveable face so it doesn’t back off, push he fixed cam down all the way and replace the retaining ring.

4) Return the driven unit to the jackshaft.

I am basing this off this article I read yesterday:
http://www.diygokarts.com/vb/showthread.php?p=19866

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robsmaze
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PostPosted: Aug 27, 2009 10:49 am    Post subject: Reply with quote

An update. I am going to adjust the spring tension on the TAV. I've always meant to play around with that a little and have never really gotten to it. One thing I did that seems to have helped is reduce the ID of the spool from 8.5" to 7". I've attached a spreadsheet that has some spool/gearing calcs and i think by reducing your ID you can actually require less torque to pick up the same load in some situations (too much coffee the other night.) I actually noticed when we tried it that deep water starts are really hard to do because there is no slow drag to get your feet planted anymore - it just yanks. But we'll see. I let you know what happens with the TAV2 adjustments...

apparently you can't add excel files as an attachment. if anyone wants to see it i'll email it to them...
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Donk
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PostPosted: Aug 31, 2009 10:07 am    Post subject: Reply with quote

It's your sprockets. 12 - 60 or 58 even on a 9hp is going to struggle with 200+ pounds regardless or your clutch tension. I would go more towards 70 on the spool end sprocket.
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peligro18
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PostPosted: Jan 23, 2012 12:40 pm    Post subject: Reply with quote

what happend?
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