150 4 stoke - popped a couple fuses

[theBaitBar]

I have a 150 4 stoke 2022 Mercury outboard on a pontoon boat. I was adding a power bimini top to the boat. Under the dash on the wire loom there was a plug labeled ACCESSORY. I connect to that and ran top in drive way a dozen times no issues. When on water the second I hit the button the motor died, no crank, trim or anything. I looked under cover and popped 1 fuse for "HELM" and another 2 amp fuse. After looking it lookes like that plug came from the engine harness. How can I pop a motor fuse only when running and what is that accessory plug for?

[EuropeanAM]

Depends on WHICH accessory plug you connected to. There's an optional Accessory Power Relay Kit, which has it's own small junction bar for connections. That would be the ONLY place such an accessory should EVER, EVER be connected together with engine wiring.

Outside of that, any BOAT accessories should be wired, powered and run totally separate from the engine.

I suspect you ended up on the wire that would power the accessory relay kit, which is powered from the HELM fuse. If so- get that wiring off that circuit ASAP to prevent the potential of damage to expensive electrical components.

Notes: We do have a dedicated 4-stroke forum here. I'll move your post over to that forum for you. Please take a few moments to look through the Announcements at the top of that Forum, and provide the Required Info when posting (serial number). Thanks!

[theBaitBar]

I removed and went to a diffent circuit for the top. I wish it did not say accessory or I never would have connected to it. The motor ran on my lift after I changed the fuses. What are the odds I damaged something electrical? Also seems odd it did not pop when motor was not running.

Depends on WHICH accessory plug you connected to. There's an optional Accessory Power Relay Kit, which has it's own small junction bar for connections. That would be the ONLY place such an accessory should EVER, EVER be connected together with engine wiring.

Outside of that, any BOAT accessories should be wired, powered and run totally separate from the engine.

I suspect you ended up on the wire that would power the accessory relay kit, which is powered from the HELM fuse. If so- get that wiring off that circuit ASAP to prevent the potential of damage to expensive electrical components.

Notes: We do have a dedicated 4-stroke forum here. I'll move your post over to that forum for you. Please take a few moments to look through the Announcements at the top of that Forum, and provide the Required Info when posting (serial number). Thanks!

[EuropeanAM]

Low odds- the fuse popped because the load on the circuit exceeded the fuse capacity.

That fuse is designed to power key-switched power and devices, the wire you selected was not intended to power high-amperage electric motors or devices (those should be powered from a separate, battery-provided, fuse or circuit breaker protected, circuit).

The reason it failed with the engine running is that the INTENDED devices were being powered by the circuit (and when you added the electric motor it exceeded the circuit capacity).