ok on my cart i built its fast but wen i first put it together and drove it it would spin the tires like crazy but only go 20-25 then 1 day after messing with it it was crazy fast and it stayed like this for bout a week i mean it was quick it beat my neighbores polaris 400 atv like nothing but now it will rev high but only top out at 30mph with a 8hp i think tecumseh nevewr had to workon it much yet

could be the clutch not grabbing right. what is it, a regular clutch, belt driven or a racing titanium clutch. oh and try bigger tires when you get it going right. and i mean big ones. try 4 wheeler tires if you can. trust me it'll be roaring then

just a heavy duty centrifical i found a few probs after driving 1 was choke moving fixed that still not as fast as it once was but i think the prob is sometimes the tire will spin on the rim and it also spind way too much i got lawn tracter tires but i cant mount them because my carts only 1 wheel drive and my hubs r a 4 bolt pattern and the wheels r 3 and i cant find 3 bolt hubs

well why not drill the hubs out to four