woe is me

[<tomryan>]

i'm working on a 80hp four stroke for an elderly gentleman. his son-in-law had repaired/modified the lights and radio at the helm and blew the 30 amp fuse on the motor.

i traced the problem to the bad fuse and replaced it. i started the boat for about 10 seconds and left. well, the elderly man went to take the boat out yesterday and the control box caught on fire at the lower plug. not good.

the lower plug to the control box smoked about 2" of the harness. the complete wiring harness is about 177 bucks, but would it be a false economy to try and replace just the burnt plug? ( and is it available? )

what would cause the control box to catch on fire?

[tomryan]

when i started the boat for 10 seconds, the out put voltage was 13.6 with everything off. would a bad or shorted coil smoke the cdi box? how can i test the coils before the new cdi and harness is installed. most auto coils have a 10:1 ratio for the resistence reading from the primary to ground to secondary to ground. does anyone know the specific readings for yamaha four stroke coils?

the boat was jump started earlier in the season.

[<boats.net>]

It sounds like you have connected 12 volts to ign. wires. You should never wire up boat wiring to ign. switch or engine wiring harness they are 2 seperate circuits. You will have test the whole ign. system (if you applied 12 volts to it, it could have burnt out a lot of componets) test all switches in control box. You need to get a Yamaha Service manual

[tomryan]

thanks mr.net, but i am innocent.LOL.

i will remove the depth gauge, fog/docking lights and radio from the stock circuitry before i procede. the only wire i found pinched ( but not shorted to ground or open) was the starter interlock wire at the helm control.

i am assuming that either the key was left on or he (the son-in-law)tapped into the yamaha gauges at the helm to power the radio.

thanks again, tom

[<tomryan>]

the new harness and cdi box have been installed, but the yamaha manual has yet to arrive. if anyone has a F80Y 1999 yamaha 4-stroke manual laying around, i have a few questions.

when the old burnt c.d.i. box was removed, there is a definitive hole burned thru the epoxy on the back side. ( besides the lower plug being burnt ) if anyone would have a schematic of the epoxied board, it might give me a clue as to what started the fire.


the plug that is melba toast is the lower red/black/blue/white plug. can anybody look and see what sensors this pluge goes to?