1975 johnson 6hp no start

[pete s]

I have a 1976 johnson 6 hp that will not start. Got it from a buddy and it ran great for him until one day it would just not start. I do have spark but on the tester but anything above 10k ohms it will not spark. Is this normal or should it have stronger spark. Upper and lower cyl are the same. It will not pop at all. I have used carb spray to try to get it going and nothing. Looking for a direction to go with it. Thanks for the help.

 

[JB]

Re: 1975 johnson 6hp no start

http://forums.iboats.com/showthread.php?t=299680

 

[jmendoza]

Re: 1975 johnson 6hp no start

Be sure the top coil and spark plug wire goes to the top cylinder, meaning the plug wires are not reversed. Does it have good compression? Are the plugs new?

 

[pete s]

Re: 1975 johnson 6hp no start

Plugs are new and it has good compresion. The top wire is also on the top. Thanks for the help!!

 

[pete s]

Re: 1975 johnson 6hp no start

Well I have great spark with the plug laid on the engine. Compression is 50psi in both cyl. Plug wires are in the correct spots. The carb base gasket is new now. It is not being flooded. Removed the flywheel and the key isn't sheared With putting gas down the carb I cant even get it to pop. I don't have any other ideas, anyone have a direction for me to go? Am I loosing spark under compression? That is the only thing that I can think of. But if that is the case what would I look for?

 

[pete s]

Re: 1975 johnson 6hp no start

Anyone have any ideas for me???? Im lost on this one.

 

[AlTn]

Re: 1975 johnson 6hp no start

spark gap should jump 1/4" to 3/8"...3/8" would be better..checked with a spark gap tool available at most auto parts stores..$7 or so...read the top secret files pretaining to omc magnetos <points, condensers, coils, plug wires> make sure they're correct...your compression numbers are low, but it may just be your gauge...fuel,fire,compression all in the right amounts at the right time...it'll fire

 

[Grumman59]

Re: 1975 johnson 6hp no start

I know they can be hard to start if the idle mixture (knob on the front) is set wrong or has been messed with.

I've managed to get reluctant Johnson 6HPs to start in initially by using a driver drill with an adapter and socket on the flywheel nut. Saves a lot of pulling and arm ache!

 

[pete s]

Re: 1975 johnson 6hp no start

At first I thought that my compression numbers were low but the more that I thought about it I think that they are within reason for an engine that is pulled over by hand. I am probably only getting 2 or 3 compression strokes verses an engine with a starter you usually go 5 compression strokes.

Grumman, thanks so much for the drill tip, ill give that a shot today. I have not messed with the idle mix knob on it but ill see what happens today with it.