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cribbageboy

40 horse Johnson

3 posts in this topic

I've got a 1973 or '74 40 Horsepower Johnson Outboard that seams to have some carb problems. There is a small brass pin maybe about 3 inches long witht threads on it that slides into the front top of the carb. I dont know what it does, but it seams to vibrate its way out (or in) and makes the engine run like [PoorWordUsage]. It will start occasionally, but wont stay running and seems to have a mind of its own when it comes to RPM's. There is a knob on the ouside of the engine with a label below it, but 30+ years have worn that to the point of not being able to read it. Could it be some type of idol adjustment? If so, how do I keep it from changing itself after i set it? Any info would be greatly appreciated.

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That there would be the low speed idle mixture screw. The reason it is backing out is because the packing is shot, or the packing nut is loose. There is a packing nut that the needle goes through. Turn the needle in until it lightly seats, back out 1 1/2 turns. Use a 7/16 open end wrench and tighten the packing nut lightly. This only needs to be tight enough to feel enough friction on the needle to prevent it from backing out. You may have to replace the packing. I have never tried to buy just the packing. I usually rebuild the carb and it comes with the kit. If it runs ok other wise and does not warrant a rebuild, ask a shop if they have the packing left over from a kit (most kits cover a wide range of carbs and it often isn't needed). I know I have lots of it so if you have a problem shoot me an e-mail and I'd be glad to send you some.

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Thanks for the help. I tried that yesterday right before my post. The packing is fine and the low speed idle screw isn't backing out any more. The problem Im having now is that it seams to flood way too easy. I try cranking it for 3 to 4 seconds, and then take out the spark plugs and they are already wet. Float pin stuck?????? Other info that might be helpful. Compression 110lb, and GREAT spark. How much is a carb rebuild if i get it done professionally? How about a new carb? Just looking at different options. Thanks for the help.

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