1968 Johnson 20hp

[themagicone]

Here is my other project i'm working on. Okay...
1968 Johnson 20hp fd-22m is the model
Bought it cheap, at first it was real hard to start, had to pull and pull and pull THEN CLINK! Pulled the recoil and flywheel off to learn that the key that turns the magneto cam and the flywheel had snaped. Well figured might at well rebuild the engine to the extent that I can so I replaced the following:
Rebuilt card w/ new float, pin, gaskets, etc. New high speed needle is on order along with new packing gaskets.
New head gasket
New thermostat/gasket
New fuel filter/gasket
Rebuilt entire ignition system, new coils, plugs, condensers , points, etc.
New magneto cam
New magneto cam/flywheel key.

Got it all back together now I can't get it to start at all. I set the points at .20 while pointing to the "M" on the cam. Flywheel spins with drive shaft freely. Just no go. It snaped another cam key the other day so got that replaced but I just can't get it started. The engine seems to have good compression, take the plug out and put my finger over and I can't turn the engine with in place.
Does anyone have any other ideas? I might have the high speed needle set wrong, how do I set that? What would cause the flywheel/cam key to keep snapping? Thanks in advance!

 

[F_R]

Re: 1968 Johnson 20hp

About that key: The flywheel and shaft tapers must be clean and dry and no damage to them or you'll never keep a key in there. The other thing is you must use a torque wrench and tighten the nut to 40-45 ft/lbs. Ignore any of this and you will wind up with damaged tapers and keyway.

 

[steelespike]

Re: 1968 Johnson 20hp

Purpose of the key is to align the flywhell not to drive the crank/flywheel.
As FR says clean and dry tapers and torque to proper specs.

 

[themagicone]

Re: 1968 Johnson 20hp

Thanks for the info, I know I wasn't putting that much torque on that. Well once I get that replaced, what would be my next step if I can't get it running? How do I set my needle on my carb? Thanks

 

[F_R]

Re: 1968 Johnson 20hp

The needle on the carb has little if anything to do with getting it started. But just to answer your question, about 1 1/2 turns open from lightly seated will at least let it run till you can fine tune it on a boat in the water. The needle is for the idle mixture and has very little to do with high speed or starting.

However, on the bottom front of the carburetor is a hex plug and down deep in the hole behind it is the high speed orfice plug. Now THAT has to be absolutely positively squeeky CLEAN!! That could be your starting problem if you are sure you have good spark and compression.