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1994 60HP 20A fuse blowing

L

LRM2

New member
Hi,
1994 60HP 2 cycle blows the 20A main fuse when I try to start. The starter engages, motor turns over for a second or so, and then the fuse blows. The fact that it doesn't blow immediately on turning the key to start makes me think it is not a dead short, but rather something drawing excessive current as the starter engages. I am 1000 miles away from my manual for this motor, but did pick up a cheap multimeter at Canadian Tire so I can do some testing if someone could point me in the right direction.
Thanks very much for any help!
Lewis
 
I would start by disconnecting the lead between the solenoid and the starter. Then see if the fuse blows. If so the problem is with the starter not the wiring.
 
You can test the starter solenoid by removing the wire that goes from it to the starter. Attempt to start, holding the switch in the Start position and see if it blows. That would tell you that the energizing coil inside the solenoid is shorted. Otherwise the problem with the solenoid would be contacts welding shut due to age pitting and that would keep your starter motor running with the key OFF.

Another thought might be a problem activating the rectifier/regulator that doesn't surface until the engine is turning and generating battery charging power. Since the fuse is down circuit from that source, it would have to indicate a moderate failure in some component/wiring fed down circuit from the fuse. On later model, higher HP engines the battery charging input from the stator (coils under the flywheel) is a pair of yellow wires.....disconnecting either will prevent your battery charging circuit from functioning. There is a caution in the service manual about not running the engine without the battery connected but I think that is due to an overvoltage condition damaging components in the rect/regl module which wouldn't occur if the input voltage is removed as stated, regardless of whether or not the battery was connected or disconnected while the engine was running.
 
Thanks to you both. I just this morning had a chance to get back to the motor. Disconnected the solenoid from the starter, turned to "start" and held it there for a few seconds. Fuse did not blow. Reconnected starter, and the fuse blew after a couple of seconds of turning the starter. So is it correct to assume that the starter itself is drawing too much current?
 
Now a new wrinkle: the fuse blows as soon as the key is turned to "on." Can't even get to "start." And it happens whether or not the starter is connected to the solenoid. That now makes me think there is a short somewhere.
I can't understand why it was taking a few seconds to blow and now blows instantly. But I'll start hunting for a crimped wire or scraped insulation.
 
OK, that didn't take long. The warning horn had a crack in the plastic cover, so I disconnected it. Starts and runs now! I'm not 100% happy about running without the warning system operational, but the telltale lets me know cooling water is circulating, and the sight gauge lets me know there's oil, so I've got most of it covered.
 
LRM2 said:
OK, that didn't take long. The warning horn had a crack in the plastic cover, so I disconnected it. Starts and runs now! I'm not 100% happy about running without the warning system operational, but the telltale lets me know cooling water is circulating, and the sight gauge lets me know there's oil, so I've got most of it covered.
Click to expand...

I decided that I wanted a dash temp gauge just like I have in my truck. So I installed a temp sending unit in the little 1/8" NPT hole that is occupied by a brass plug on my 4 -3 cyl engines. Now I can see exactly what and when the block water temp. Comforting to say the least. I chose that over the popular water pressure gauge for my own reasons. I understand the difference in functionality and different requirements for different boating situations.
 
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