4.3 blows 15a fuse when you throttle up

[RGatt3030]

About 4000 rpm. Kept it there for about 20-30 seconds at a time but wasnt sure that the muffs supply enough water to allow that without burning something up after a prologued duration. With throttle fully applied there must be some kind of limit or governor because it waffles between 3900 and 4000 but wont wind up past that. But that would be pretty consistent with top rpm on this boat historically on water and with a top speed between 36-40mph. Something seem off about that or does that seem like normal performance?

 

[dubs283]

4000 rpm in neutral is not good, no reason to go more than 1500 rpm in neutral. alternator should be putting out max voltage at 1000-1200 rpm

most likely the rev limiter was engaging

according to the info on the flame arrestor, WOT is 4400-4800, that is under a load with the correct propeller

 

[RGatt3030]

Boat idles fine and those rpms were engaged with throttle engaged in forward gear. Still though, why blow that fuse 5 times in a row on the lake but not in the driveway? And why no energy fluctuations as rpms increased? You would think that if that fuse blows repeatedly on the water, then revving on trailer should at least cause an amperage spike in that fuse if it were related to rpm’s. So what could it be?

 

[alldodge]

Anything above 1500 rpm's can burn the impeller. Watch your temp gauge closely next time out

 

[dubs283]

Boat idles fine and those rpms were engaged with throttle engaged in forward gear.

that's even worse, the drive unit is not designed to be be spun out of the water at high rpms like you posted, anything off idle in gear with no load has the possibility to damage drive internals

under a load means in gear with the boat in the water, every turning component of the engine/drive behaves differently when under load.

 

[dingbat]

Still though, why blow that fuse 5 times in a row on the lake but not in the driveway? And why no energy fluctuations as rpms increased? You would think that if that fuse blows repeatedly on the water, then revving on trailer should at least cause an amperage spike in that fuse if it were related to rpm’s. So what could it be?

You have a short to ground in a “wet” location.

The bilge pump circuit would be my first guess.

 

[dingbat]

You have a short to ground in a “wet” location.

The bilge pump circuit would be my first guess.

 

[stanggt88]

Did you ever get this figured out? was it the temp sensor (87-866089)