old johnson motor questions

[Marcus]

I have an early 70's 35 HP johnson motor I am trying to get running. Me and a buddy worked on it for a bit but we are stumped. When I take the spark plugs out and try to turn it over it spins over no problem , but when we put the plugs in I could neither pull (which i usually can) or cannot get the electric start to start the motor. Feels like too much compression? really like to get this figured out

[Skipper]

 your exaust may be plugged tight. Mud sand and clamshell bits can do it.

Engines either sieze or loose compression at the end, I have never seen one gain compression.

I have the service manual for '73 to '90 Johnson-Evinrude 2 to 40 horse if you need specs

[geothefisher]

Your engine should have a compression release mechanism on it.  It usually rides in a track on your manual starter, and moves a lever left and right to operate poppit valves that are on the cylinder head.  This unit only operates while starting the engine, and releases the compression, making it easier to start.  Check your engine and see if it has this item.  If it does, check its operation to see if it is operating properly and actually opening the little poppit valves.  If you have any questions, PM me.  I have been working on OMC products for around 30 years, and will give you all the help I can via email.