Popping fuses at ignition switch

ahein

Petty Officer 3rd Class
Joined
Dec 7, 2002
Messages
89
I've recently developed a problem with burning the ignition switch fuse when I try to crank the engine over.<br /><br />Engine/Ignition info: 1987 Volvo Penta AQ-260 (GM 350) with a three position key switch (Off,Run,Start). The engine was rebuilt last year. The starter and the switch are only a year old.<br /><br />The odd thing is that it doesn't do it every time I start the engine. But sometimes I go through a whole box of fuses before I can get it going. My initial thoughts are faulty ignition switch or a dead spot in the starter that is causing it to draw high amperage.<br /><br />I need your help with ideas that could cause the fuse to pop, and help with testing the switch and starter. I have a multimeter but am far from proficient at using it.
 

Haut Medoc

Supreme Mariner
Joined
Jun 29, 2004
Messages
10,645
Re: Popping fuses at ignition switch

What the starter draws has nothing to do with the key switch, believe it or not. When you turn the key to 'start' the solenoid closes and tells the starter to crank, but all that power is delivered through the fat red wire.....Does it blow when the key is in the 'run' position? I suspect that you have a chafed wire somewhere either in the harnesses or one of your accessories that only has power when the key in in the 'run' position.... However if it only does it when cranking I would follow the yellow/red wire from the key to the solenoid. Disconnect both ends, add a jumper wire of suitable guage and see if that solves your problem....JK
 

Haut Medoc

Supreme Mariner
Joined
Jun 29, 2004
Messages
10,645
Re: Popping fuses at ignition switch

Whoops! almost forgot....By using this jumper wire, you also bypass the neutral safety switch, and the engine can start in gear! BEWARE! ....JK
 

rbezdon

Senior Chief Petty Officer
Joined
Jun 20, 2004
Messages
689
Re: Popping fuses at ignition switch

I had an old small bloch Chevy Impala that had the starter solenoid start to fail with the result being too much current draw in the start position. It actually wleded the ignition switch contacts and got the starter stuck on all the time. I had to go under the hood and disconnect the battery to stop it. I cut the wire and started it external from the switch but the final cure was to replace the starter/solenoid.
 

ahein

Petty Officer 3rd Class
Joined
Dec 7, 2002
Messages
89
Re: Popping fuses at ignition switch

The fuse only blows when trying to crank the motor. I can turn the key to the run position and tilt the outdrive up and down without any problems. I've never had the fuse blow while the engine was running.<br /><br />So it sounds like a chafed wire may be the culprit? I'll pull the instrument panel off to look for any suspect wires and try to follow them back to the engine. I'll also try running the jumper wire to the starter solenoid. I'll let you know what I find out. Thanks.
 
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