Hard starting 1966 20 hp Johnson

[manitoba1]

"I have a 1966 20 hp Johnson w

"I have a 1966 20 hp Johnson which is extremely hard starting cold. Once running, the engine runs well but getting it going initially is hard. Often it'll backfire with full choke. I haven't had it long and don't know the engines history. Seems to have good spark and plenty of fuel. Any suggestions as to what I can do to get it starting properly (less than 50 pulls)?"

 

[jwbmarine]

"clean/rebuild carb,make sure

"clean/rebuild carb,make sure u have no water in fuel,..make sure your throttle roller is not half gone away,..make sure your handle is staying in the start position,not moving on u..u of course,should run a spark gap test,and compression test,just to verify things there are ok."

 

[manitoba1]

I made up fresh fuel in a new

I made up fresh fuel in a new tank and ran a whole bunch of Seafoam through the carb. I believe the handle is remaining in the start position. Not familiar with the throttle roller? What kind of gap should be on those plugs. Haven't checked the compression but it takes a pretty good pull on the started rope to turn it over and it would appear to have decent compression.

 

[jwbmarine]

"put some j6c champions in it,

"put some j6c champions in it,and gap at .030"

 

[ko4nrbs]

"The roller rides on the magne

"The roller rides on the magneto cam.
There is a diagram at this web link.
Look here:
http://www.duckworksmagazine.com/06/columns/max/index12.htm
Bill"