1970 60 hp johnson ignition conversio

[sean mathews]

i,ve got a 1970 johnson 60hp three cylinder that th amplifier box quit on. i tried an inductive coil conversion with ballast resistor and condenser. motor now runs great up to about 3000 rpm but kinda just hits a wall at that point. considered msd box but not sure if i should waste the money on msd setup or just install aftermarket amplifier. i have read tons of posts here about these conversions but no one has seemed to follow up on there results. im afraid if install msd and such it stil wont rev above 300 rpm. so does anyone out there have any ideas. thanks

 

[F_R]

Re: 1970 60 hp johnson ignition conversio

Like you, I have seen tons of people try that car coil scheme, but haven't yet seen anybody come back and tell what a great success it was. Kind of tells you somethng, right? As for the rest of the question, I have no clue.

 

[durban]

Re: 1970 60 hp johnson ignition conversio

one way of doing it
http://forums.iboats.com/showthread.php?t=527612

 

[sean mathews]

Re: 1970 60 hp johnson ignition conversio

yeah i,ve not heard of anyone succeeding either. thinking if i can milk it through the end of salmon season this way i will go ahead and change it back to cdi next spring. just kinda sucks when it takes ten minutes to get to the fishing hole instead of four.

 

[durban]

Re: 1970 60 hp johnson ignition conversio

just a thought about your conversion , when i did mine the most important thing is to change the firing order , other wise it wont work , try changing yours & see what happens

 

[sean mathews]

Re: 1970 60 hp johnson ignition conversio

what order should i try? it really runs good up to about 3000 rpm i believe the problem with the higher rpms is the dwell time. it seems the coil cant completely charge between the opening of the points. ive also considered the msd conversion i,ve read abot but i have reservations about that to. in essence im asking the automotive coil to function at the speed equivilant of a four stroke running at 10000 rpm. i really just want to make till the end of salmon season after that the boat will not get used again till sometime next spring and i will most likely just buy a new amplifier at that time

 

[durban]

Re: 1970 60 hp johnson ignition conversio

because you have lobes on the camshaft for the points to spark i don't know how you can change the firing order you have 2 sets of points aye , when the lube is on no 1 piston it will fire right then the crank turns the 2nd lube comes up & fires the other points , & in between the 2 points firing it seems that that's where you lose out , try & get it to fire on 1 set of points only , a suggestion only . i had to change my firing order because i never used the lobes to send the spark off , cheers hope you win m8t

 

[sean mathews]

Re: 1970 60 hp johnson ignition conversio

thought about that. and might actually give it a try. by doing so in theory one set of points should allow the coil to charge for a longer duration. not to mention i would have a spare seet of points. the real decision is do i remove the first or second set. i saw the pictures of your conversion. good work im impressed. i am a heavy equipment mechanic by trade. this two stroke boat motor thing has me digging deep in my mind back to my teenage years when i was a dirt bike fanatic. so im still brushing up on my knowledge. if i do figure out how to make thi work i will post what solved the problems.

 

[durban]

Re: 1970 60 hp johnson ignition conversio

i would get no1 piston in the firing position & see witch set of points line up with the lobe , then use that one . dont forget to mention who gave you the idea k , if it works , best of luck

 

[durban]

Re: 1970 60 hp johnson ignition conversio

you will also have to wire it up in series some how 1, 2 ,3 1 ,2 3 you get what i mean , k hope it works

 

[sean mathews]

Re: 1970 60 hp johnson ignition conversio

gonna check this out. need to look at it im stil not surehow the dual points work. they are both wired together. i think the first set opens and the second se opens before first set closes. will figure it out as soon as i open it back up. thanks for the thought though.

 

[durban]

Re: 1970 60 hp johnson ignition conversio

the other thing you could also try is make it fire with 3 coils , the set up you have is that the coil does not build up enough charge for the plugs that's why you cannot increase in rpm cause there insuffiecent spark .

 

[sean mathews]

Re: 1970 60 hp johnson ignition conversio

had it on water yesterday with the only change from the time before being points gapped at .018 instead of .010. darn near made full rpms. thinkin of opening gap up to .020 and see if i cant get that last little bit out of her. of course that is after i soulder the brush back on the starter tha led me to getting towed back to the dark. good news though brought home a big salmon.

 

[sean mathews]

Re: 1970 60 hp johnson ignition conversio

JUST A FOLLOW UP set points at .018. and have had no issues sense motor runs greaat through all rpms. so the conversion sems to work fine. good luck too all