Winky Blinky

[Double Hook]

I have a 1998 225 two stroke Yamaha pushing my parker and it appears to run rough idling when cold between 1200 - 1600 RPM and when warm drops down to 800-900 Rpm . Would a Winky light tester diagnose if a sensor is out?

 

[DaleH]

Sounds like your carbs need to be adjusted. Get the OB warm and do this ONLY IN the water, not on muffs, as the OB needs the exhaust backpressure.

1. Write down where idle adjust screw is NOW, i.e., #1 = 7 to 1 o'clock, #2 = 9 to 3 o'c, etc.

2. Adjust top most carb facing the motor. Turn IN 1/4-turn, see if RPMs increase or decrease. If she stalls, you may have to turn OUT. The goal is to find where the motor runs at it highest RPMs during the carb adjustment for that carb.

3. Repeat for carbs 2 - 6.

4. Take her out for a spin, put it up on plane and then back to idle. If she stalls or stutters, REPEAT steps 1 thru 4.

NOTE - you cannot adjust one carb independently and think you're done ... anytime you adjust or tweak one, you MUST check all ...

... I just saved you $80 for the OEM manual or $30 for the crap after-market ones ...

 

[TomS]

Is this motor new to you?

I ask because depending on the exact engine you have, some of the larger Yamahas drop 1-2 cylinders at low RPMs and they tend to run rough and shake a bit until you push the RPMs up and all cylinders start firing.

Also pretty typical for the RPMs to run a bit higher with a cold engine and then drop down to your true idle RPM when engine is warmed up.

I'm overstepping a bit here, but I assume that if you are asking about a winky-blinky, you have a fuel injected engine and not one with carbs.

To answer your original question, yes, a winky-blinky will tell you if one of your sensors is not working correctly, but only if the malfunction occurs when it is hooked up. In other words, there is no memory/history to it, it will only indicate a bad sensor reading at the time it happens.

Give us some more background - whether this is something that just started happening after years of working differently, or is the motor new to you and just seems to be running differently than you expected?

-- Tom

 

[Bryan 2530]

Is it an OX66?


If so your O2 sensor and sniffer tube need to be cleaned.

Also what you described is typical for that motor. It is supposed to do that.

How does it run after it warms up?

 

[miky2884]

yes to what Bryan said, that motor will rev upwards of 12-1600 rpm's when cold then if the o2 sensor is working correctly it will kick down to 6-7000 rpm's when warm.

 

[DaleH]

FYI, attached to this post is the article on how to DIY clean the infamous Yam O2 sensor, by the noted OB guru Bill Grannis:

 

[Brent]

Sim has one too
http://www.simyamaha.com/category_s/1841.htm

and

http://www.simyamaha.com/Yamaha_Outboar ... s/1806.htm