72 johnson 40hp carb rebuild help

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drunkincamper

Recruit
Joined
Jun 8, 2004
Messages
2
I have a 1972 40hp johnson that needs to be rebuilt. I bought the repair kit today(#385356). I bought a manual but for my carb. Theres not too much in detail for my questions.<br /> My first question is how do I set the 1 needle on the carb? I've heard turning the needle in all the way and back it out 1 1/2 turns(finger tight, or tight tight?). Is this setting for my carb also?<br /> My second question is about a couple of silver caps that are included. How do I get the old caps off? Do I need a glue to hold the new ones in?<br /> <br /> My third question is when I last started it, it was leaking oil. I take it, its becuase of the needle setting was wrong. Do I turn the needle in or out to fix that when it happens next?
 
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Paul Moir

Admiral
Joined
Nov 5, 2002
Messages
6,847
Re: 72 johnson 40hp carb rebuild help

Question 1: Finger tight (just seated) and back out 1 and 1/2 turns is your starting point. With the engine warmed and in gear, adjust it in until you begin to misfire, and then wind it out until you reach the highest rpm.<br />Tight tight damages the soft brass needle.<br />Question 2: To remove the core plugs, carfully drill the centers out with a 1/8" drill bit. Be careful that when you cut through, you don't let the drill bit drop and hit what's under the plug. There's only about an 1/8th or so between them. Then carefully pry out the plug with a punch or very small screwdriver.<br />To install the new ones, put a bit of 1000 sealer (or other gasoline proof sealer) on the outside of the new plug, then set it in the hole so the rounded side points out. Then flatten the rounded side with a hammer and punch. That'll push the rim out against the carb body.<br />3) I don't really understand your question. I could see how the carb would flood if it was leaking past the float valve needle, but I'm thinking you mean the low speed mixture adjustment needle. If so, you tighten against it's packing with the packing nut which surrounds the adjustment until the needle is snug and doesn't leak.<br /><br />Hope this helps, and welcome to Iboats!
 
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