Tayana -48 Owner's Manual page 103

The thruster has an unexpected low performance
Check
Check voltage at thruster when running
Solution
If less than 10.5-V the thruster will not perform at
specified effect
Check
Check that all the brush spring sits correctly on the
brushes in the electric motor
Solution
If one or more brushes are loose/has no tension from
the brush spring, the performance will be low
Check
Check that the propeller, gear house and tunnel is free
from growth/barnacles etc.
Solution
If there is growth in the tunnel, this will disturb/block the
water flow and especially barnacles on the propeller will
greatly reduce performance.
3.23.7 Generator
Generator Operation
The panel controlling generator operation is on the AC electric
panel located in the nav. station. Generator starting battery is
12-volt system. Capacity of this battery is 120 AH.
Before Starting the Generator
Before operating generator become familiar with the procedures
and instructions in the generator manufacturer's owner's manual
（1） Follow the pre-start checks as outlined in the generator
manual
（2） Ensure the AC power select switch is not on GEN.
Positions
（3） Check that generator sea cocks are open
（4） Check the generator lubrication oil level
102