2002 Yamaha F115 4stroke relays

[Mulletman]

Can anyone tell me the purpose of the two relays on the front of the engine? I don't think its the trim and tilt. Thanks.

[rodbolt17]

they are for allowing a low current circuit to control a high current circuit.

[boscoe99]

The main relay and the power trim and tilt relay are located at the front of the motor. As Rodbolt so succinctly notes they are used to allow a small amount of current to control a larger amount of current flow.

Think of the PTT system. Particularly the electric motor that turns the pump. It may draw upwards of 40 amps or so. That takes a large wire. So a large wire is used just between the relay and the electric motor. Two small wires run from the trim and tilt switch to the relay to tell the relay what it should be doing. It is not practical to run a large wire all the way from the motor to the throttle handle and then back to the electric pump motor.

Pretty nifty huh?

[Mulletman]

Yep. Pretty nifty. Thanks. Now if I could just figure out why this rascal won't
develop more rpms.

[rodbolt17]

well, its not a relay if that helps.