yamaha F80Y cdi question

[tryan]

i am try to diagnose the cause of a small fire at the c.d.i. box. i have the new harness and c.d.i. box installed, but i will not fire the motor untill i can determine the cause. i have a yamaha manual on order, but recieved it. bummer.<br /><br />the lower plug melted with a red/black/blue/white wires and there is a small 1/4" diameter hole blown out the back of the epoxy coating an inch and a half in from the lower plug and about 1/4" from the edge of the housing. <br /><br />the owner wants me to fire up the boat, but i refuse to do it until the manual arrives.<br /><br />history..... i pulled the boat last fall and told him the nav lights where inoperable. the son-in-law 'repaired' the lights and installed a stereo which resulted in a dead motor. i replaced the 30 amp fuse on the main harness and the fire occured on their next outing. no wires where chaffed in the cowling, but i believe either the tach wire was tapped into at the helm or something has shorted out the ignition circuitry. i have not tested the coils, but i have never seen a bad coil set a control box on fire. would a bad bridge rectifier cause enough voltage to burn up the cd?<br /><br />can anyone help with the color codes at the helm for the stock yamaha gauges or give any insight. <br /><br />thanks guys. <br /><br /><br />red right return

 

[Ray Neudecker]

Re: yamaha F80Y cdi question

The tach wire is green, yellow and blue are switched hot, red is hot all the time and black is ground. Other connections are by way of harnesses with plugs from the engine to the guage.I would certainly check to see where the radio hots and grounds are connected and disconnect before thinking about starting the motor. There is a possibility that the stereo even if hooked up correctly pulls too much current and dropped the voltage significantly on the CDI. You may also have a cooked rectifier and lighting coil. I would at least ohm for a short in both. If not shorted they won't hurt anything if you fire the motor. Normal tests for them when motor is running for voltages. I can picture many problems the radio may have added. If they left it on and ran down the battery, then hooked up the jumper backwards (common problem) there goes the CDI. May be the number one cause of CDI failure. A talk with the operator might clear up the picture and you can at least warn him of what is happening so a repeat is not your or Yamaha's problem. GOOD LUCK.

 

[tryan]

Re: yamaha F80Y cdi question

thanks ray for the wiring code. i was feeling lucky ( with out the manual ) and checked for continuity to ground on all the power feeds after i removed the power leads to the radio. she started right up and the c.d.i box stayed cool to the touch. output voltage was good, so the rectifier was spared. i will check the other sensors when the service manualk arrives.<br /><br />the overheat alarm triggers at idle, so i have more fun in store after i clean up the wiring at the helm. <br /><br />i only have a couple hours of work involved, but i wish people would take better care of such fine equipment. the fire extinguiser powder is almost all gone, but it's going to take a day with a tooth brush to get it out of all the nooks and crannies.<br /><br />it struck me as odd to see the mitsibishi emblem on the most electrical hardware under the cowl.<br /><br />hey ray, do you race hydro's, flatties or pickle forks? i have a 60 correct craft mahogany starflite utility with a graymarine fireball 225 hp, a '69 cc v-drive and a '72 cc ski nautique. i love to be out on the water.<br /><br />thanks, tom

 

[Ray Neudecker]

Re: yamaha F80Y cdi question

I seldom race myself anymore, but spent years in true tunnels and V-bottoms. Most of the Gang for whom I am engine builder and or crew chief race V-bottoms, Mod V's and a couple of hydros. All drag racing now, even though I raced roundy round, river races and drags before I got old and grey. Some very nice old boats you have. Glad everything is working out on your repair.