I've a Hustler Fastrak ride on mower (has a 20hp Honda GXV620) which has always had issues starting, which I thought was battery related, its since decided to really not want to start and I think I have tracked the problem down.

How much voltage to the battery should the regulator/rectifier be providing ?

If I jump start the mower and get it going at full revs, when I measure the power at the battery it is 22v .. which is way to high and probably has trashed the battery which is why it doesnt like to start ... so that would be the regulator at fault right ?  When they fail can they output to much ?  Or if they fail do they just die and output nothing ?  Does the input AC voltage have and effect on the output DC voltage ?  Would too much AC in equal too much DC out ?

Thanks!