Carb settings for 71 40hp

[foxjohnc03]

My 71 Rude 40 is not running right and has a miss at idle which I believe is caused by a gummed up carb. I am going to take it off and clean it up but have a few questions before doing so. The carb has no high speed rich-lean adjustment, right? The plate on the front of the carb has the writing on it but there is just a hole. Also, what is the correct # of turns for the low speed mixture? I know that you have to tweak it but there has to be somewhere close that I can set it to get it running. Also on the carb bowl there is an adjustment screw. What does it do? I have no clue. Thanks a million.

 

[foxjohnc03]

Re: Carb settings for 71 40hp

Also, how much will a carb rebuild kit set me back for this motor? Took apart the carb and found one clogged up passageway after another. I browsed the forum and found a message from someone that said like $14 for a rebuild kit, Is this right. I believe that it was Sierra marine which is a division of NAPA. Do they keep them in stock or would I have to order? I really want to get out on the water this weekend.

 

[foxjohnc03]

Re: Carb settings for 71 40hp

anyone have a clue?

 

[Joe Reeves]

Re: Carb settings for 71 40hp

You Betcha.... More than a clue.<br /><br />(Carburetor Adjustment - Single S/S Adjustable Needle Valve)<br />(J. Reeves)<br /><br />Initial setting is: Slow speed = seat gently, then open 1-1/2 turns.<br /><br />Start engine and set the rpms to where it just stays running. In segments of 1/8 turns, start to turn the S/S needle valve in. Wait a few seconds for the engine to respond. As you turn the valve in, the rpms will increase. Lower the rpms again to where the engine will just stay running.<br /> <br />Eventually you'll hit the point where the engine wants to die out or it will spit back (sounds like a mild backfire). At that point, back out the valve 1/4 turn. Within that 1/4 turn, you'll find the smoothest slow speed setting. <br /><br />When you have finished the above adjustment, you will have no reason to move them again unless the carburetor fouls/gums up from sitting, in which case you would be required to remove, clean, and rebuild the carburetor anyway.<br /><br />Carb kit price is about right, and they should be in stock.

 

[foxjohnc03]

Re: Carb settings for 71 40hp

Thank you very much, I have the carb kit and will be on the water in a few hours.