Evinrude 6 HP 1979

"My Evinrude 6hP twin cyl star

"My Evinrude 6hP twin cyl starts and runs fine at mid to high speeds but the low rpm is quite rough running. I have mixed fresh fuel at 50:1, compression tested( both cyls at 110 pulling over by hand) and replaced the plugs, gapped at 0.040. The plugs are NGK BS6 I think although the manual reccommends Champion plugs with a fancy code. I am not a fan of champion as I have had loads of failures but will give them a try if you think its worth it. i overhauled the carb which was as clean as a whistle. I say overhauled but mean cleaned it out ( no new gaskets ). The only thing is that the mixture screw can be adjusted right in and the engine runs a bit better but does not die. If I disconnect the fuel, the engine runs a lot smoother and the revs pick up as the fuel runs out which seems to me like the carb is at fault. Any suggestions most welcome. Thanks."

Normal carb adjustment with th

Normal carb adjustment with the mix screw is to screw it as far in as possible to where the engine has the highest and smoothest running at lowest possible throtle setting. Then back it out aprox 1/8 turn and check that the engine does not stall or hessitate when accelerating. It seems that either your needle or seat is damaged. Try to replace the needle.

"Graham I just wanted to let y

"Graham I just wanted to let you know that the Gap should be .030 I have the same motor as you and I just checked my Owmers Manual (Original Manual) and it calls for .030

Also I would buy Champion Plugs Either of the following part numbers should be fine # L86C or 5933. These engines are extremely finicky if you try to put a plug in there that should be. "Q-Series" inductor types (used in Copper Plus & Premium Stainless) are the only OMC approved replacement plugs for engines specified. Use of other types may cause engine misfire.

If I were you I would go to www.sparkplugs.com and use the drop down menus until you get to your engine and purchase a few directly from them. Thats what I do but only because I cannot find those exact plugs around where I live anywhere.

Hope this helps."

"Thanks for the info so far. I

"Thanks for the info so far. I'm going away next week and although I am fairly confident that it won't let me down, it's nice to know its working efficiently."

"Just one more question, when

"Just one more question, when I take the short reach plugs out of my engine you can see that the threads carry on as if there should be long reach plugs in it. Is this correct? The plugs installed at present are NGK BS6 which I know are wrong but on a picture of the correct Champion Q plugs shows short reach as well???"

"Just to update, I fitted Cham

"Just to update, I fitted Champion plugs of the correct type and re ran the engine. It seems a bit better but was still not right. I took the low speed needle needle valve adjustment screw out and found that it had been sharpened up to a pin type point for about 8mm. I think this is not shutting down thw mixture sufficiently so have ordered a new adjuster. will post an update when it arrives."

New adjuster arrived and measu

New adjuster arrived and measured it with original which was about 10mm shorter. fitted new slow speed mixture screw and engine is running sweet. Someone for some reason decided to grind the original down...