1972 85hp johnson no spark and problem with 1978 85hp rude

[bigkeebouskie2002]

ok first i was wondering if anyone could throw a link out on how to do the car coil swap for the cd box on a 1972 85hp johnson(points) also having problems with my dads boat 1978 85 hp evin. when we run boat close to wot it will bog down then power back up over and over again sometimes pumping the fuel buld will help sometimes it won't any ideas on what is causing this and what steps i can take to check it thanks for any help in advance

 

[ledgefinder]

Re: 1972 85hp johnson no spark and problem with 1978 85hp rude

There isn't a link. <br /><br />OMC ran a number of battery-powered points/condensor/coil ignitions in the 1960s. Have a look through the wiring diagrams for those & see if it's familiar ground to you. <br /><br />You'll want to provide resistance on the 12V running through the points (commonly called a "ballast resistor"). OMC used to use a special type of wire for this. Also, you may need to balance the inductance of the coil with the capacitance of the condensor to assure the right field collapse speed - not trying to 'snow' you, just not sure myself here. <br /><br />If you get a system working well, let us know!