Ignition fuse continues to blow

[Thatoneguy]

The ignition fuse on my 2002 Glastron SX175 with a 3.0 Volvo Pentax GSM-B continues to blow on me. This first happened last weekend about 30 seconds after starting up the motor. After replacing the fuse and starting it again, everything was fine and the boat went about 400 ft before everything shut off; blown fuse again.



After getting it back to the lift I checked all the wires but haven't been able to find anything where a short could be occurring. There was corrosion on the starter so I cleaned it up. I tested it after the clean up and it ran fine for almost ten minutes until I took off to get on plane. I tried to see if a new fuse would get me back to the dock but the fuse went as soon as I turned the key to run.



As a little background, I recently replaced the u joint bellows and gimbal bearing because I had taken on a lot of water the weekend before. The boat is new to me and it appears that the bellows were neglected. The water had filled the bilge about to the bottom of battery. I'm wondering if the water could have caused an issue with the starter or the starter solenoid.



As I stated, there is no obvious short under the dash, by the engine, or the throttle control. I do have a multimeter but I'm unsure of where to start in my search for the root cause. Any help is greatly appreciated. Thanks in advance!

 

[bruceb58]

Look first for any wires on the engine and running near the exhaust manifold. If the engine was ever overheated, the insulation of a wire could melt down to the point where it would now short out. Check all wires on the engine for abrasion damage.

If you can get a fuse to blow by just turning the ignition on without starting the engine, pull the man over boar lanyard and see if it blows. If it does, it's an issue in your dash.

The fact that it takes a little while makes me suspect a wire rubbing on something.

 

[Thatoneguy]

Thanks for the input. There does look like a little melted insulation on a ground for the intake. I started the engine and watched this wire and couldn't see anything move. I tried the man overboard switch as well and it didn't blow the fuse.



The issue seems to be very sporadic. Sometimes it'll be less than a minute and other times it'll be a few minutes. I've been testing it while on the lift so there's less shaking than on the lake. When it runs longer and the temp gauge gets to the center and give it more throttle, it'll pop. Other times I can move the throttle without the fuse going. Sometimes when the fuse just went and I swap it the new one will go immediately when I turn the key to run.



Recently, I ran the engine for a bit, it shut off and the alarm when for a second before the fuse blew. I'm searching for other possible short circuits but haven't found anything. I'm not sure where else to look at this point. Any more pointers would be greatly appreciated!

 

[Thatoneguy]

Another update. Last night I had the engine running for a few minutes and went to trim up the motor and the fuse blew as soon as I moved that switch.