Check at NAPA for EXIDE GC-3 batteries and see what they cost,these are what manual calls for and might be cheaper than what your looking at,or at least more AH in them.......takes 4 of them....
Exide type GC-3 6 volt 75-91 AMPS Trojan type T-90 or T-1900 6 volts 75-91 AMPS
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