850 85hp no spark

[FAST FISHER]

I have an 85hp Mercury 1975 BLUEBAND serial 9070050.THUNDERBOLT Fired up ok, run like a dream. Then just died. nuffin, no spark any where. Any clues anyone. THANKS

 

[Clams Canino]

Re: 850 85hp no spark

On the side of the switchbox with 4 poles check for +12V at the red one and then +12v at the white one when the key is turned on.<br /><br />Assuming the key switch and wiring are OK, that means either the switchbox or the trigger in the distributor failed. Report back.<br /><br />-W

 

[FAST FISHER]

Re: 850 85hp no spark

Thanks for the advice I will give it a try.

 

[FAST FISHER]

Re: 850 85hp no spark

Right I have 12 volts on the red and nuffin on the white.Does this narrow it down. Thanks

 

[FAST FISHER]

Re: 850 85hp no spark

anyone?

 

[Laddies]

Re: 850 85hp no spark

you don't have compete circurt in the system could be the the switch, if the choke works problely not that. Ck the plug in and if it's not ether of them you have a broken wire

 

[FAST FISHER]

Re: 850 85hp no spark

Ok i will give it a go. Thanks

 

[Clams Canino]

Re: 850 85hp no spark

White outta go hot when you turn the key to ON / RUN.<br /><br />-W

 

[FAST FISHER]

Re: 850 85hp no spark

Hello again. I turned on and left on for approx 10 minutes or so checking every min or so and white stayed cold not even warm. Does this make any sense. Checked plug in was right home and clean. Thanks

 

[Clams Canino]

Re: 850 85hp no spark

By "hot" I meant read +12v. hehe<br /><br />Red is +12 all the time, white only when the key is on.<br /><br />-W

 

[FAST FISHER]

Re: 850 85hp no spark

nope nuffin!

 

[Ben Konopacky]

Re: 850 85hp no spark

FF;at the key switch,with the key in the on pos.check if you have 12vdc between black & white orpressthe choke button &hear if it clicks .if its got dcv & clicks,check the pins in cable ,make sure they are tight & cleac spread the male contact a little to make it tight ,then check for dcv on the white at the box (disconected) you should have dcv at this point.<br />hope you get suffin!!!

 

[FAST FISHER]

Re: 850 85hp no spark

Hi I have taken the control apart. At the switch the orange/red/yellow/gray/black wires are conected to the switch the white and brown wires aint conected to nothing. The terminals of the choke button are bare-no wires. The wires insde the control were joined together with blue tape.

 

[FAST FISHER]

Re: 850 85hp no spark

It looks like my control has been used to gain a few spare parts while the boat has been left unatended and the wires to the switch just put back anyhow. The nutral switch is missing. The choke button has no wires to it at all. I have a workshop manual but the wiring diagram ie the letters on the switch which to connect which wires to is unreadable. Has anyone got this information what wires go where.

 

[Ben Konopacky]

Re: 850 85hp no spark

FF; If your term. on the switch are marked A,B,D,E&F this might help! Red to"A",Yellow TO neut. sw.then to "B",Gray To one side of choke button,Black to "D" which also goes to neg on tach.,Salmon (your Orange most likely)to "E",White to"F" then to the other term. on the choke button from there white goes to plus side of tach. if used. the Brown is the signal to the tach.? do you have a manual on this merc.?? that would help now & in the Future pays for itself..

 

[FAST FISHER]

Re: 850 85hp no spark

Thanks for the information Ben. I do have a manual but the area around the swithch on the wiring diagram is unreadable.The nutral switch is now missing will the engine still be ok to start without it and the terms on the choke are u/s as well. Are these parts still avalilable?

 

[FAST FISHER]

Re: 850 85hp no spark

The switch terminals are marked looking from the back "A" with a "S" below far left "B" far right "C"in the center"M" top "I" bottom left "M" bottom right. This is now becoming a nightmare!!!!!!!!!!!!!!!!!!!

 

[dolluper]

Re: 850 85hp no spark

A=purple S=yellow/red B=red <br />C=yellow/black<br /> <br />M right=black M left=black/yellow the I not sure lights the panel? neutral safety has black/yellow and other connector black THE other end of your box connector to panel D=black A=purple B=gray C=tan

 

[Ben Konopacky]

Re: 850 85hp no spark

By-passing the neut.sw.the engine will start in gear (thes is a bad practice).I can't see why the parts would not be available .your Merc. dlr.or iboats might have or order them for you.

 

[Laddies]

Re: 850 85hp no spark

you have gotten yourself worked up over a fairly simple problem, STOP, take a deep breath, get a wiring diagram, when make sure you are getting 12 volts to the control box, then simply us a jumper and make sure it will return to the motor to ck out the wires in the harness, if they are good use the jumper to bypass the switch functions one at a time till you find the problem or find another control and harness--bob