Logo

Carburetor adjustment question

kentrx1

Member
1987 Yamaha 70 hp. Never could get carbs that were with engine when I got it to run well at mid throttle. Put on a set from a 1989 70 hp Yamaha. Runs really well at mid and open throttle now. Trying to adjust idle mixture screws and set at 1 5/8 as manual for 1987 says. Can tell any difference on any three of carbs turning one full round in or out at idle. Only time I hear rpm increase is when screw almost alway in—maybe 1/2 round out. Always heard to never run lean so I have left at about 1 1/2 out. Any thoughts or suggestions? To the ear it does sound a little rich to me there, but never cuts off and idles ok. In gear at idle a tiny bit sluggish till I bump throttle up but does not choke out.
 
Back
Top