40 Amp reset-120 HP Merc I/O

[danforthdeckie75]

Have a 1974 Starcraft Holiday w/120 HP Merc Cruiser I/O Engine Ser # 3507461. Runs perfect- Except occationally everything stops because 40 amp breaker has tripped. (occurred once when hit another boats wake at 3/4 full speed)-very random-When resetting braker this does not always work, then after awhile the breaker will hold closed and everything is perfect again. Any ideas as to where to look for problem? Thank you very much.

 

[Trent]

Re: 40 Amp reset-120 HP Merc I/O

Could be a weak breaker? Id check the output of the alternator. Volts and amps. Check the condition of the cannon plug for the engine. Battery connection and engine grounds clean and tight??

 

[Buttanic]

Re: 40 Amp reset-120 HP Merc I/O

Could be a bad spot on a wire that shorts to ground for an instant when the boat hits a wave a certain way and pops the breaker. I have seen this happen on cars where hitting a bump in the road would blow a fuse.