1971 50hp johnson

[dubzzz]

I Have Compression I Have Spark./ But It Will Not Start. Last Summer I Had Some Issues With The Top Idle Screw (needle valve) Vibrating loose. This Year It Will Not Start For ME At All Is THere A Test Or A Way To Get The Needle Valve(s) Set In The Right Spot? Or Just Keep Tweaking And Adjusting Until It Starts?


http://www.boats.net/parts/search/BRP/JOHNSON/1971/50ESL71S/parts.html

Thanks Everyone!

 

[jbjennings]

Re: 1971 50hp johnson

There should be a nylon stop that the low speed needle screws into and expands, causing the needle to be swedged into position and not move. Do you have that?
I'd GENTLY screw the low speed needles all the way in, back off about 1 1/2 turns, and then gently tighten about 1/16 of a turn at a time until I got them all where they need to be for a smooth idle. If the low speed needles aren't in ball park of correct, then it will likely not idle at all, or start and run.
Have you cleaned the carbs and replaced with new kits?

Last of all, could you specify how you checked for spark? If simply grounding the plug to the block and looking for a spark, that's not at all a reliable test for spark.
There's a handy article in the "top secret thread" at the top of this forum by Joe Reeves which more clearly outlines the proper procedure for tuning carbs.
Good luck,
JBJ