Are you asking how to tell if it's wired to charge, or how to tell if it is charging?
For the latter, a voltmeter across the battery will tell: If it reads above the nominal (at rest) voltage of the battery while the motor is running, it should be charging. Normal charge voltages should be in the 13.2 (idle speed) to about 14.4V (high rpm) range. Should have at least 12.2V with motor off.
Yeah need to know if its is wired up already to charge battery
If its electric start it should be wired to charge via the same cables. Some of the tiny (eg 6hp) sizes have AC output to run lights and such but no charging capability. But there's no such model as an electric start 90hp without an alternator to charge the starting battery. Unless you think the alternator's been disabled?
