69 55hp amplifier conversion

My brother has a 1969 55hp johnson that we converted from an amplifier to car ignition coil <br />the problem now is that it fouls the plugs after about 10 minutes of driving are we missing something here?

Re: 69 55hp amplifier conversion

Help any one have any ideas?

Re: 69 55hp amplifier conversion

I could be grasping at straws here but would changing the sparkplugs from a surface gap style to something like a champion j4c help ?<br /><br />any help would be great ,i've search other posts but cannot find an answer

Re: 69 55hp amplifier conversion

Did you ever resolve your problem? I recently did the same conversion for the same motor and I too had plug problems. After a day of using it, the plugs started to misfire and now I am wondering what plugs I should use with this system.

Re: 69 55hp amplifier conversion

Your back to battery ignition with a Champion J4C plug

Re: 69 55hp amplifier conversion

Thanks! will try the J4C plugs.

Re: 69 55hp amplifier conversion

Buckstr did changing your plugs to j4c help.My brother gave up on his last year and is wondering what to do.

Re: 69 55hp amplifier conversion

I have a 1969 85hp Johnson with points and CDI ignition system, so I'm always interested to read about this stuff.<br /><br />I recall someone mentioning in a post that the points for this early CDI system could be expected to wear out faster if you converted to the automitive style ignition system. I don't know myself as the amplifier on my engine is still working, but I doubt I'll be spending the $400 bucks for a new one when it dies.<br /><br />In the few posts I've read about this conversion, I don't think there has been much talk about Ballast resistors. If you're using a automotive coil that's intended to be used with a ballast resistor, and you don't have the ballast resistor in the circuit, you may be frying the coil. <br /><br />Coils designed for seperate ballast resistors are designed to operate below 12V, not at, or above 12V. This may be further agrivated by the poor voltage regulation on some of these motors. I don't believe my 85hp has a real voltage regulator at all.<br /><br />Perhaps someone else can add a comment about automotive coils and ballast resistors? <br /><br />Sean

Re: 69 55hp amplifier conversion

check the plug firing voltage, it has to be 5-7 Kv minimum.<br />also check the timing to insure it occurs at the correct time. <br /> trons is trons and if the coil output is of sufficent kilovolts the plugs could care less if the primary coil voltage was from a capacitor discharge(battery CD in this case) or a conventional coil. what kind of condeser did ya use to absorb primary coil voltage when the points open ?<br />points are a switch, however they are electrically rather noisy. as that magnetic field collapses it will induce a voltage in the primary windings as well as the secondary windings. the function of the condenser is to absorb a certain amount of it as well as the spike when the points first open.

Re: 69 55hp amplifier conversion

I have a 69 johnson and made the conversion to a <br />coil one thing that I did not read you saying was<br />that you used a resister off the negative side of<br />the coil.Using the J4C plugs along with the resister might just solve your problem. Hope this helps you

Re: 69 55hp amplifier conversion

this is a old post but i tried this conversion 4 years ago i could not get any speed out of my 55.i broke down and bought a amplifier it worked great.i recently changed the ignition switch and fried the amplifier my own stupidity i somehow hooked the gray rpm wire to a purple power duuu. i tried the conversion thing again but i still have no power in motor.every time i puled the plug out of#3 its cold and soaked in raw gas.their is spark their with the tester.any help on this would be great.thanks.solved it.cracked distributor cap.thanks anyway

Re: 69 55hp amplifier conversion

i have converted this 55 with a spark igniter assy from a 74 toyota it runs great\lots of spark\parts can be found in your local scrap yard\here are some pictures.http://photobucket.com/larry_030

Re: 69 55hp amplifier conversion

I have successfully converted my '71 100hp Johnson to an MSD Ignition 6TN (6 Series) CD ign box and a MSD blaster high vib coil. I have run it 3 times this summer so far and it runs as well or better than before. My old CD amp box had gone intermittent and they are $200+ and may last 5 seasons. I decided to try something new and thought about the auto coil + condenser + ballast resistor conversion or using MSD. Heard some peoples concerns with extra point wear using the auto conversion. I got my MSD box on e-bay used for $70 and some I missed were around $30, then the coil was new for $45. So I think I improved my ignition longevity by using this system instead of the orig equip that has reliability issues.

Re: 69 55hp amplifier conversion

I have heard of a lot of people substituting a car coil, condenser and resistor for the amp on the 3 cylinder motors. Never heard anybody say it was successful. Still haven't.

The 4 cylinder is a bit different. It has a more conventional points dwell.

Substituting a car transistorized ignition might make sense.

Re: 69 55hp amplifier conversion

70wellcraft said:

I have successfully converted my '71 100hp Johnson to an MSD Ignition 6TN (6 Series) CD ign box and a MSD blaster high vib coil. I have run it 3 times this summer so far and it runs as well or better than before. My old CD amp box had gone intermittent and they are $200+ and may last 5 seasons. I decided to try something new and thought about the auto coil + condenser + ballast resistor conversion or using MSD. Heard some peoples concerns with extra point wear using the auto conversion. I got my MSD box on e-bay used for $70 and some I missed were around $30, then the coil was new for $45. So I think I improved my ignition longevity by using this system instead of the orig equip that has reliability issues.

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I am intersted in doing this change over and have a MSD Coil currently, Could you give me any direction on this and I see this post was about 4 years old still doing well without burning point or plugs. What steps did you take lots of guys looking to do a quality conversion they want like $300.00 and change for the new amplifier and they are very reliable- I have the 1969 V-4 w/ Points.

Your input would be appreciated- been fighting this all day no spark but points okay, wierd part is I am reading ground on my amplifier blue wire. when I put the light on the positive post it blinks as if it were working backwards.