Johnson 3hp running on one cylinder

[newvintageusa]

Hi All
Long time lurker 1st time poster!
I have read this issue before on several forums and the thread just goes dead so either the problem was resolved without results or thank yous or the poster just gave up. I will definitely follow up.

62 Johnson 3 hp. Pretty nice clean unit picked up from a family friend. Did the usual new coils, plugs, points, rebuilt carb, good fuel flow. 79/81 PSI compression.
Spark good on both cylinders. Will jump a 1/4" gap.
Motor starts and runs only on the top cylinder. I determined this by disconnecting the top and bottom plug wires to see which one it was running on.
So now to figure out what is going on before tearing into this thing. It seems like the lower cylinder is not getting any fuel. Plug is not dry as a bone but definitely not flooded. Tried a little fuel in the cylinder still won't fire on the bottom cylinder maybe not enough at in there? Seems like spark but it's good when checking it.
I was thinking it's the reeds? Does each cylinder have its own separate reed? I was going to start there and then the head gasket even though good compression.
Any help would be appreciated.
Thanks
Mark

 

[racerone]

The 2 cylinders are seperate as far as processing air is concerned.----Remove carburetor to check reeds for the lower cylinder.---Could be something in there holding one open.

 

[newvintageusa]

Thanks should have dug in there when the carb was off. I'll start there.

 

[newvintageusa]

Reeds looked OK. Did some cleanup and will re-install tomorrow night hopefully.

 

[newvintageusa]

Cleaned up the manifold and reeds. Lasered out some gaskets. Carb started leaking took care of that. Did a few pulls and started up but will have to wait until after work tomorrow to run on the lake to see what we have.

 

[newvintageusa]

No Title

Chip in the lower cylinder at the corner, see pic. Good compression but no vacuum. The top ring mist have been sealing the cylinder on the way up and then pulling away on the way down. What a head scratcher until we pulled the head off.

Now we need to find a piston....