1977 Merc 850 85hp No Spark!!!!

[gr8t8pt]

Please Someone Help Me! I Have A 1977 Tracker Bass Boat With A 1977 Mercury 85 Hp Outboard. Im Not Getting Any Spark From The Coils. There Is 4 Coils On The Passengers Side And None Are Getting Power I Check This With A Test Light. Does This Boat Need A Kill Switch Installed Because There Is None If So How Can I Bypass This. Please Someone Help Me. Thankyou John

 

[gr8t8pt]

Re: 1977 Merc 850 85hp No Spark!!!!

It has electric choke system and when i push the key in it clicks and motor turn over great! Im trying to fix this boat for my son were not having any luck! ANYONE!!!!!!! PLEASE HELP!!!!!!!!!!!

 

[Motor Boater Bill]

Re: 1977 Merc 850 85hp No Spark!!!!

Check your wiring carefully, the 1970's motors are notorious for bad wires. Have you ever had this running? Know any history?

 

[gr8t8pt]

Re: 1977 Merc 850 85hp No Spark!!!!

no i just got this boat. there was some bad wires on the motor so i replaced them with some new ones. there is a small hole under the throttle looks like a kill switch went here but there is nothing. i pulled out the main wires and it looks like someone spliced into them maby for a kill switch. how can i bypass this switch.

 

[gr8t8pt]

Re: 1977 Merc 850 85hp No Spark!!!!

There are 7 wires running into the ingnition key switch all these are in 1 harness. The colors are
Brown: this wire gets power when you crank the motor.
Yellow: this gets power when you crank the motor.
Grey: this has power when the key is on the run position.
Black: no power this is a ground i think.*Note* wire is spliced
Orange: this gets power when you crank the motor*Note* wire is spliced
Red: this has power all the time.
White: when the key is on the run position it has power*Note*wire is spliced

Can anyone tell me why the orange,white,and black wire are spliced and do you think this could be where a kill switch was.

 

[gr8t8pt]

Re: 1977 Merc 850 85hp No Spark!!!!

took kill wire off switch box left side middle wire GOT SPARK!!! YES!!! can i run this with this wire off what do i need to do now???

 

[Motor Boater Bill]

Re: 1977 Merc 850 85hp No Spark!!!!

I'd suggest you find where the kill wire is bad and fix it--being able to turn the motor off has certain advantages for safety and convenience, to say the least.

 

[gr8t8pt]

Re: 1977 Merc 850 85hp No Spark!!!!

do i need to install a new kill switch? and if so how do i wire this up! thanks

 

[Chris1956]

Re: 1977 Merc 850 85hp No Spark!!!!

First of all, here are the proper functions of the wires.

Brown is tach signal. it runs from one of the AC connections on the rectifier.
Red is +12V all the time.
White is accessory power from the keyswitch.
Yellow is starter solenoid
Grey is choke solenoid
Black is ground
Orange is the ign killer wire. It is grounded when key is off. This is the proper place to wire a kill switch with a lanyard. the switch should connect orange to black when activated.

You need to test the function of the ignition key switch. It should connect power to white (red to white) when in the on position, and connect ground to orange when off. It should connect power to white and power to yellow when in the start position. White wire should be connected to one side of the choke switch, as well as run back to the motor where it is unconnected.

 

[gr8t8pt]

Re: 1977 Merc 850 85hp No Spark!!!!

thanks alot that helps me alot i bought the new kill switch now im going to wire it up will post new news asap thanks again

 

[gr8t8pt]

Re: 1977 Merc 850 85hp No Spark!!!!

removed the mercury switch wired the kill switch with orange on one side and black on another side "WORKS GREAT" thanks everyone im going fishing!!!!

 

[ifeeltheneed4speed]

Re: 1977 Merc 850 85hp No Spark!!!!

First of all, here are the proper functions of the wires.

Brown is tach signal. it runs from one of the AC connections on the rectifier.
Red is +12V all the time.
White is accessory power from the keyswitch.
Yellow is starter solenoid
Grey is choke solenoid
Black is ground
Orange is the ign killer wire. It is grounded when key is off. This is the proper place to wire a kill switch with a lanyard. the switch should connect orange to black when activated.

You need to test the function of the ignition key switch. It should connect power to white (red to white) when in the on position, and connect ground to orange when off. It should connect power to white and power to yellow when in the start position. White wire should be connected to one side of the choke switch, as well as run back to the motor where it is unconnected.

This is BY FAR, the best thread Ever posted on this site!!!! THANK YOU, Chris1956! I just saved a Whole lot of money by switching to Chris!!!
This info could probably solve 75% of these problems without ever having to buy a part! A simple toggle switch is the best alternative! I now have a chrome push start and toggle ignition NO MORE KEY! My original stator probably had some life left before I tried to tear it apart to rebuild.
Its no lie that these old engines need to be COMPLETLY rewired! I have own 4 of these now same year. Every one of them had rotten wires. Dont stop just at the motor! The wire harness in the boat also needs checked.!!!! A lot of people make the mistake of "sealing" the power and ground together with electrical tape. These two wires are enemys and should be kept sepperate. If both are rotten and falling apart they can create a red hot ark dirrectly from your battery causing fire and damage. Make sure you use an inline fuse or battery shut off close to battery.