2004 Johnson 90 blowing main engine fuse

PghBill

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Joined
Apr 24, 2020
Messages
6
I have a J90PLSRR so the 2 stroke model.
I just started blowing fuses when turning ignition key. I have read all posts I can find.
My tach has not been operational for some years but never affected the engines performance.
The Trim n Tilt works fine after fuze is replaced.
I recently installed a new power pack then ran it all day with no issues.

The next weekend I replaced the exhaust Base Gasket and so had the lower unit off. I also replaced the water pump.
I started outboard in driveway and it ran fine on a hose.
Took it to the water and it started right up and the water was streaming out to confirm the pump was performing.
The engine warmed, idle came down and I shifted into gear. it was idling fine then stopped.
returned to neutral - Would not crank - fuse was blown.

Troubleshooting I have tried
Removed the lower shroud to be sure no wires were pinched. Everything looks fine
So now have disconnected yellow wire to the starter solenoid and still blew. Reconnected that.
Disconnected both temp sensors - still blew with turn of key. reconnect those
Used button on control box to increase throttle out of gear and surprised engine cranked, Tried this a second time and fuse blew.
Checked under dash and ignition switch and wires look fine. all accessories operate independent of ignition switch.

Help! need boat for a moose hunt next month in norther Quebec.... need to fix and regain confidence in it!
 

Crosbyman

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Nov 5, 2006
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Chris1956

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Mar 25, 2004
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The main fuse blows when the ign power (purple) is somehow directly connected to the ground (black). You shifted the motor and then the fuse blew? Do you have the control with the ign keyswitch in it? If so, maybe a wire is rubbing inside the control.

If the ign keyswitch is on the dash, look for melted wires in the boat harness, and then the engine harness. Look under the dashboard and at the motor near the connectors.
 

PghBill

Cadet
Joined
Apr 24, 2020
Messages
6
The main fuse blows when the ign power (purple) is somehow directly connected to the ground (black). You shifted the motor and then the fuse blew? Do you have the control with the ign keyswitch in it? If so, maybe a wire is rubbing inside the control.

If the ign keyswitch is on the dash, look for melted wires in the boat harness, and then the engine harness. Look under the dashboard and at the motor near the connectors.
 

PghBill

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Joined
Apr 24, 2020
Messages
6
OK - I have fussed with this all day.
The fuse blows when the key is turned on after 2-3 seconds. I can turn it on and off again quickly or even crank the motor without blowing the fuse as long as I do not leave ignition in the on position.
 

PghBill

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Joined
Apr 24, 2020
Messages
6
OK - I have fussed with this all day.
The fuse blows when the key is turned on after 2-3 seconds. I can turn it on and off again quickly or even crank the motor without blowing the fuse as long as I do not leave ignition in the on position.
OK - I have fussed with this all day.
The fuse blows when the key is turned on after 2-3 seconds. I can turn it on and off again quickly or even crank the motor without blowing the fuse as long as I do not leave ignition in the on position.
Shifting the motor does not seem to have any effect. But I have checked the control box and the wires there all look OK and no signs of shorting. Yellow and yellow red are there plus wires for TNT all look ok.

I followed the link from the "dreaded 10 AMP fuse". Mine is not an ecotec but I did jump the wires on Main 6 wire cable. Red w/Purple and Purple. Wires 4&5. Fuse did not blow so that may suggest it is in the wiring harness of dash. ALso jumped 5 &6 an fuse did not blow that is red w/ purple and purple w/ red - I only did that by mistake when reading the other post.
 

racerone

Supreme Mariner
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Dec 28, 2013
Messages
38,802
Remove wire from the ELECTRIC PRIMER VALVE ( red lever thingy ) and see what happens.
 

PghBill

Cadet
Joined
Apr 24, 2020
Messages
6
THE SOLUTION - Disconnected the rectifier completely and engine ran - no fuse blown.
Connected wires back all except the gray wire for the tach.
Starts and runs fine.
Problem is in the tach but I can live without that

I'll carry fuses just in case!
 

saltchuckmatt

Commander
Joined
Jul 19, 2019
Messages
2,859
THE SOLUTION - Disconnected the rectifier completely and engine ran - no fuse blown.
Connected wires back all except the gray wire for the tach.
Starts and runs fine.
Problem is in the tach but I can live without that

I'll carry fuses just in case!
Doesn't your tach have all the warning lights?
 
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