18hp vanguard briggs

Hi, I have a chance to buy two 18hp vangaurd motors for $150 canadian. The guy also said he's willing to throw in a 3 year old 18hp briggs thats been siezed but I can use it for parts. The only things I need for the engines are gas tanks, but I've seen them both hooked up to his own gas tank which he need and they run just fine. MY question is is there a cheap clutch system that would work with this engine on a go kart? THats what I was thinking of using the engine on becuase right now (aswell as a mini bike) I'm helping my friend build a go kart . I have seen the comet clutches with the drivers and driven pulley system, but they are quite pricey(150 for the driver clutch). I was wondering if there was another set up I could use that wouldnt cost too much. Could I tune the engines down? I wouldnt normally use an engine this big but the go kart frame we have is big enough to accomodate such an engine and brand new engines that are 8-10 hp are already well over 500 dollars. Any help would be greatly appreiciated - Andrew

the govenor can limit the revs and therefor cut back the power band... yard equiptment engines may be rated to 5hp or 8hp or w/e but unless you adjust the govenor to allow higher revs it never reaches its powerband peak.
but why wouldnt you want 18hp...hell id do the simple stuff like advancing the timing by knocking the flywheel forward a degree or two and make an adjustable bracket for hte magneto and just do lots of test drives advanceing timing untill you start to noticable loose power or detect knocking.

The reason I'd use an engine like this is because it's so cheap. At first we were looking at the 6.5hp tecumseh powersport engines, but they're $279.99 can and thats really cheap compared to some of the other briggs and honda engines around here.

So would a clutch rated at about 9hp work on an engine like this? Would it just slip and not engage, or would it engage but not last as long, and break quicker?

i asked why wouldnt you want 18hp...not why would you. you asked if the engines could be tuned down ;)
the clutch holding isnt the matter ou need to be addressing, you need to see if there is a clutch that matches the output shaft diameter and key configuration that is kart-applicable.
if you dont want to use a Torque-A-Verter set up then a cyntrifical clutch and sprcket is your only other option, if you wanted variable gearing ive seen bike-like gears set ups on both home made karts and mini bikes but the chain didnt last long with a 5hp motor...

I've found a centrifugal clutch that will fit but it;s rated for a 9hp engine. My friend is quite sure it will work but you just can't accelerate very quickly or else it will slip. He said it's the same on his outboard motor on his dads boat. He said if you hit the throttle all the way it will slip, he said you just have to let it build up with ease and then you'll be going. I'd like to use a toque-a-verter but they're too costly. That first link I posted is a torqur-a-verter. The go kart frame and everything is almost complete. Hopefully i'll be able to get some pictures up in a week or so. :grinyes: