late 70's/80's Johnson 9.9 carb tuning

[59Ford]

Recently got a Johnson 9.9 outboard, I think it's late 70's to mid 80's, it's all white and has the idle know on the port side and carb tuning knob by the choke.

Anyone know the stock carb settings, if I pull the plastic knob off and turn the screw all the way in, how many turns out is the factory setting. Also is there a low speed needle on the carb too? It runs pretty good but not quite perfect, just want to reset anything the previous owner might have messed with.

Thanks

 

[Vic.S]

Re: late 70's/80's Johnson 9.9 carb tuning

Tell us the model number and we will tell you the exact year.

The adjustment you see on the carb is the slow running mixture.

The basic setting is to gently seat and the come out 1.5 turns.

See Joe Reeves' instructions on the Engine FAQs board to properly adjust the mixture screw.
http://forums.iboats.com/showthread.php?t=167352

See Leroys Ramblings on the side bar HERE for practically everything you need to know about the 9.9 hp engines

 

[59Ford]

Re: late 70's/80's Johnson 9.9 carb tuning

Thanks, I'll check those out.

Model #: 10RL77A
Serial #: E4641801

 

[59Ford]

Re: late 70's/80's Johnson 9.9 carb tuning

Also what should the plug gap be. It seems like it misses every so often when idling slow and when we had it in the water(on a boat) running WOT every 30 seconds it would cut out for a slit second then keep going like normal.

 

[Vic.S]

Re: late 70's/80's Johnson 9.9 carb tuning

that model number makes it a 1977 model.

Plugs should be QL77JC4 or QL82C gapped at 0.030"