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1974 johnson 6 hp ignition issues

E

edgarop

New member
I have a 1974 6 hp that i cant seem to get firing correctly. the compression on the cylinders is 85 and 90. I installed a new head gasket, thermostat and impeller. the motor had been over heated slightly as well. i checked the cylinders and pistons and no scurring to be found anywhere .The plugs are gapped correctly. it runs on 1 cylinder, when i pull the top spark plug wire nothing happens and keeps running the same and when i pull the plug it comes out wet. the bottom cylinder is nice and dry. the points have to what i think is pitting or arching on them so i sanded them with 1500 grit didnt smooth them out all the way so there is still pitts on them. it is gapped to 0.020 on both sides. Is the coil grounding wire suppose to have plastic shielding over it? what could be wrong? thanks
 
Re: 1974 johnson 6 ignition issues

The coil ground wire does not require shielding. Pitted points will result in faulty ignition (caused by a faulty condenser usually). Double check point appearance and setting..... set so that a .020 gauge will pass thu but a .022 will not and have C/Shaft key aligned with the fiber portion of the point C/Shaft cam contact when setting.

Switch coils to see if the problem follows the coil.... after switching, if the top cyl now fires and the bottom does not (problem reversed), then obviously the coil is faulty.
 
Re: 1974 johnson 6 ignition issues

I'd replace the points and condensors as filing a pitted point is not the best idea, then check the plug wires too and make sure nothing is arcing out to the stator plate. I just had to change the wires on a customers 10 h.p. for that reason. The coils rarely fail unless they crack and arc out. I've seen where the coils have been replaced by someone careless and they either pinch the trigger wire or the kill button wire. Another fault is not getting the high voltage output wire properly pushed into the new coil.
 
Re: 1974 johnson 6 ignition issues

the coils have very tiny hairline cracks does that make a huge difference? i did an ohm test on them and they read out 3.7 ohms that is ok based on a manual that i have. iS this true?Ive had cracked coils on my 1973 Evinrude 115 since 3 years ago when i bought it. And it runs great never let me down. how can we explain this?
 
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Re: 1974 johnson 6 ignition issues

They can be cracked and not arc through. There is rarely any internal problems with the coils and testing impedence will not indicate an external arcing issue. I like to ensure dependable perormance and coils should be replaced when they begin to crack. I personally wouldn't take your 115 with the cracked coils to one of our remote Ontario outposts, but around here you can get by if it starts to act up. The way we load up our boats we need all cyl running at 100%. If the coil is only cracked on the top you have a better chance of survival. They only cost about $15 each anyway through Sierra.....they make an excellent replacement.
 
Re: 1974 johnson 6 ignition issues

should i just switch them on the timing plate. i have an extra armature plate with all the goodies on it. It is off of a 1958 10 hp QD-19 It looks like the same stuff. does it fit? the coils look the same so do the points. but i have a new set of points on order.
 
Re: 1974 johnson 6 ignition issues

Switching the coils on the armature plate is the route I'd take. If the non firing coil then fires, then obviously the coil is okay.
 
Re: 1974 johnson 6 ignition issues

thanks you joe i installed new points and condensors and still runnning crappy. But i continued with you advice and the hairline crack on the coil had devoloped a pin hole on the bottom side that was arching to the armature plate. i installed 2 coils from a 1958 QD-19 and bingo that solved the problem. BAD COIL. thanks. i have another Q im not getting any water at idle. but at 1500 rpm i get a good amount of water. how can i tap a pee stream into this old motor?
 
Re: 1974 johnson 6 ignition issues

Glad to hear that you found the coil problem. I'll turn this over to another member as I'm leary of drilling into a powerhead for that water telltale setup.

Sound like you have a weak failing water pump assembly.

Thousands of parts in my remaining stock. Not able to list them all. Let me know what you need and I'll look it up for you. Visit my eBay store at:

http://stores.ebay.com/Evinrude-Johnson-Outboard-Parts-etc?refid=store
 
Re: 1974 johnson 6 ignition issues

The small exhaust port just above the waterline will mix with water if all is well. You should see good water spray even at idle. You've been working on this motor and probably turning it backwards. If the waterpump impeller is old and rotten sometimes a finger will flip backwards or even break. Make sure that you blow out all passages in case something is plugged up with a piece of rubber impeller. Also make sure the seal is ok below the pump where the driveshaft enters the lower unit. Impeller drive pin must be stainless or it will rust away, careful not to loose it.
 
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