evinrude yachtwin 4 HP slow running adjusment knob ??

1stmatevista

Recruit
Joined
Apr 14, 2009
Messages
4
i have a 1989 evinrude yachtwin 4 HP ! Does anyone know how to use or adjust the slow running adjusment knob on the front of the engine ( next to the fuel tap and choke knob?!?! thanx
 

Vic.S

Rear Admiral
Joined
May 4, 2004
Messages
4,719
Re: evinrude yachtwin 4 HP slow running adjusment knob ??

If the carb setting has not been interfered with set it in its mid position !

You can try altering it once the engine has warmed up. Turn it clockwise until the engine just starts to falter then back off until it runs evenly again. Pull the knob off and refit it in its mid position .

For the full explanation of setting the mixture see the first section of http://forums.iboats.com/showthread.php?t=167352

I find with my 6hp that it helps to turn it fully clockwise (to weaken the setting) start on full choke, then turn it fully anticlockwise (enrich the mixture) at the same time as pushing back the choke knob. Then slowly retuning to the mid point as it warms up. But that's me! Once set correctly there should be no need to touch it.
 

film495

Petty Officer 1st Class
Joined
Apr 8, 2009
Messages
285
Re: evinrude yachtwin 4 HP slow running adjusment knob ??

get your motor to running temperature.

run at high speed and set the high speed / rich lean setting so the motor runs at the best / fastest rpm.

then run the motor at a slow idle - and perform a similar operation with the slow speed adjustment, there is a sweet spot where it will run a little better than any other setting. you just turn it back and forth and you will hear the motor slow on each side of the correct setting.

I believe the biggest factor of having the slow speed setting correctly adjusted is the motor will start a little better and you can idle down a little slower before the motor will cut out.
 

Vic.S

Rear Admiral
Joined
May 4, 2004
Messages
4,719
Re: evinrude yachtwin 4 HP slow running adjusment knob ??

set the high speed / rich lean setting
It has a high speed mixture adjustment?
Can you point that out on the parts diagram please?
 
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