Blowing main eng. 20amp fuse??

[walleyehed]

30hp Merc, Mod# 1A30412DD, S/N 1B049811 Fuse is fine at Idle but if power is applied (RPM going up) fuse blows before even getting on-plane. I'm TS'ing this long distance and am wondering if anyone may have an inkling as to whats going on here. Trying to help a youngster that's 1500 miles away from me and I have no literature on this outboard.
Thanks in advance for any input.

 

[GA_Boater]

It sounds like maybe a bad regulator. Can the kid use a meter? Check the voltage across the battery as the revs rise and before the fuse pops. Shouldn't be much over 14 volts.

 

[sam am I]

Sounds like what GA has indicated............The battery and/or other electrical 12V device/s will typically and can have a tendency to want to clamp/hold their own supply voltage all supplied from the regulator to around this level to be happy. If a failing voltage regulator is allowing these devices voltage increase above their happy voltages, the current will increase (I = V/R) e.g., if "V" goes up and "R" remains roughly the same, then according to the formula, "I" (current) has to go up. If the current exceeds the fuse rating, the fuse pops.

 

[roscoe]

Could be as simple as a wire grounding out as the timing plate or throttle linkage is moving.
Check stator and voltage regulator wires, along with moving linkages. If something rubbed a wire long enough, it can easily wear through the insulation.

 

[GA_Boater]

Could be as simple as a wire grounding out as the timing plate or throttle linkage is moving.
Check stator and voltage regulator wires, along with moving linkages. If something rubbed a wire long enough, it can easily wear through the insulation.

I was thinking along electrical lines, but from the mechanical side this very well could be the cause. I hope so cuz those regs aren't cheap.

 

[racerone]

Looked inside the control box ??