1972 Mercury 800 80HP Thunderbolt

[Ogogo]

Good day to you all,

I bought myself a 1972 Del-Magic boat that has this motor attached to it. I am in process of building new spark plug wires. I'm afraid the last thing I have to replace would be the Distributor assembly. I have changed the coil (which is getting spark), switch box and all wiring. I have learned a lot since I have pulled this thing apart quite a few times. The fellow I bought it from started the wiring job on it it. Now the other day I viewed a picture of my distributor online and there was a springy thing which has been identified as the brush. The last owner had pulled it out and through it in the floor of the boat, which I picked up all parts and put them in a coffee can when I bought it so I found it by chance..... I reinstalled that and still to no avail have I been able to get it started. No fire what so ever. My next step is to replace the plugs and get the new wires installed as I think they are original to the motor, and to test compression. Tested old plug wires with a voltmeter and they had really crappy resistance. Also bought a spark tester so I will finally be able to see if I am getting spark to the plugs.

The big question I have is, how does the trigger in the distributor assembly work? Is it sending the signal as the rotor turns to the switch box to tell the coil when to fire, then sends the spark from the coil to the distributor through the brush and onto the rotor head and then to the plug?

I really want to keep it original as I love this little boat.

Thanks for your time

Serial# is 3427457

 

[Faztbullet]

The big question I have is, how does the trigger in the distributor assembly work? Is it sending the signal as the rotor turns to the switch box to tell the coil when to fire, then sends the spark from the coil to the distributor through the brush and onto the rotor head and then to the plug?

You got it,,,,,

 

[Chris1956]

Triggers are part of the distributor housing and are not cheap ($250+) to replace. Rotors are permanently attached to the shaft and are $200+ to replace. Make sure the wires are good and test the ignition system for proper operation. Hopefully everything works.

 

[CharlieB]

You need either the factory service manual or the CDI Igntion Troubleshoting Guide to tell you exactly which wires to test, and how, to determine your spark problem. The CDI Guide can be viewed or downloaded here.
CDI Troubleshooting-Guide-Inside-Pages.pdf
Follow the steps and it will prove if a part is defective. Only then will it be safe to spend money as there is NO return on electrical parts.