No Sparks

[cpasseno03]

Anyone know of a wiring schematic on here for a 1965 johnson 40 hp? I cannot get spark, and the (what I assume to be to seperate) Ignition wires arent getting hot from the switch, (two black ones labeled "M" on the key switch. I think they should both be hot when key is "on" any suggestions??<br />Thanks<br />Craig

 

[Joe Reeves]

Re: No Sparks

Craig..... Those two black wires lead to the two points and condensers. There should be absolutely no voltage going to those wires at any time. Voltage applied to those wires would destroy the points, condensers and both coils.<br /><br />The engine has a magneto ignition system and is self contained. When the key is off, the two "M" terminals (the black wires) are connected internally within the ignition switch, effectively shorting out the magneto. With the key on, the "M" terminals are disconnected, allowinbg the magneto to generate ignition (spark).<br /><br />Adjust the points to .020 with the fiber portion (rubbing portion) aligned with the flywheel key. Make sure the flywheel key is set vertical (the straight side of the key being straight vertical, not aligned with the crankshaft taper.<br /><br />The flywheel nut must be torqued to exactly 105 foot pounds... any less will allow the key to shear and throw the engine out of time.

 

[cpasseno03]

Re: No Sparks

Thanks Joe! I have tried all that... Still no spark. I did have spark once on the top cylinder, just turning the flywheel by hand. But only a few of them. I have cleaned and set the points, which appear to have been replaced recently with very little time on them. Condensers also (just going by the cleanliness) I have not checked those yet. What else can I try???<br />Craig

 

[cpasseno03]

Re: No Sparks

Also...Where can I decode the serial numbers?<br />J2514630-old motor<br />J2709905-my new powerhead

 

[steelespike]

Re: No Sparks

Craig, You should get yourself a manual.<br /> Your ignition works similar to a lawnmower <br /> When your switch is on it is open when off it <br />is closed shorting the points to ground.<br /> Ignition generates its own voltage.There is<br />a saftey switch that shorts the points in the event of a runaway as under a broken shearpin.<br />Disconnect the wire from the points at the safety and if you disconnect the harness from the motor<br />and crank it, you should get spark.<br /> If no spark check the points and the condition of the coils.

 

[cpasseno03]

Re: No Sparks

thankyou thankyou.....ill go give it a shot and most likely, report back

 

[cpasseno03]

Re: No Sparks

nothng...spun the old powerhead and got a few woosy sparks, guess ill go get a meter and chck coils, condensers....<br />Craig

 

[Trent]

Re: No Sparks

 

[OBJ]

Re: No Sparks

Craig....<br /><br />You haven't said anything about the condition of the coils. If the outer epoxy like covering on the coils are cracked, the coils are probably blowing to ground which would be the plate they are mounted to. Remove the fasteners and lift the coils and look underneath. If you see a black spot on the plate and/or coil, the coils are shot. Also, check that the points are opening and closing. With the flywheel off, put the flywheel nut back on and turn the shaft clockwise and observe the points are opening and closing at high cam. Removing the spark plugs will help make the turning easier. If not, set the point wiper on high cam and re-adjust point gap.<br /><br />Jim

 

[RICKRICK1]

Re: No Sparks

Craig, have you checked each wire inside the distibutor. Had a similar problem and found a wire that goes to the points was bad. I got intermiten spark and thought it was the points, found out it was a small wire about 2 inches long that was broken inside the wire insulation. Changed out the wire and all worked ok. Hope this helps as your distibutor wiring is probably the original wires.

 

[cpasseno03]

Re: No Sparks

The point gap is set, I changed a condenser and got spark on both, a healthy spark, but it didnt seem to hit every single time it shouldve. either way, back together it went, fired it up and ran for a few minutes, lost the top cylinder! I also changed both coils and put on the ones from the origional motor which did work as I checked them right beforehand on the old powerhead. Now what???<br />Thanks for all the help!<br />Craig

 

[cpasseno03]

Re: No Sparks

Success! one of the insulating jobbys on the points was melted a bit, along with 1 or 2 bad coils, and a condensor.<br />Thanks for the hints<br />Craig