blown fuse

[fishheadny]

hi, i have a merc 225 1995 outboard motor the main 20amp fuse on the motor blows intermitently, sometimes on the start up sometimes under power, i changed the starter and selonid but it did not help- anyone have any ideas. thanks

 

[GA Paramedic]

Re: blown fuse

do you know that it is supposed to be a 20 amp fuse? not that is correct or may not be safe, I would be inclined to try a 30 amp fuse. If you have a short somewhere, it will probably blow that one too before the whole motor goes KFB but that is what I would try first, personally. Try to find what it is suppsed to be and go from there. It would be in a service manual or a owners manual if you have one.

 

[Dunaruna]

Re: blown fuse

Hi bw, welcome to iboats!!<br /><br />Only one thing can cause a fuse to blow, excessive amps, that usually means a partial or dead short in a circuit. The trick is to find that circuit.<br /><br />Make one of these from a headlight globe and wire it as per the picture<br /><br /> short tester<br /><br />Disconnect the ground cable from the battery, connect one of the test leads to the battery and the other test lead to the disconnected battery cable. At this point, the battery is disconnected and you cannot cause any damage, no matter what you do.<br /><br />Turn the ignition on, wriggle wires, operate the trim etc etc. You get the picture? You are trying to CAUSE the short to occur. When the headlight globe illuminates, you have found your short. The brighter the illumination, the more severe the short.<br /><br />You cannot cause any damage testing this way.<br /><br />Bob