Low Speed Adjustment Screw

[RNispiros]

I have a question on adjusting the Low Speed Adjustment screw on a Mikuni 38BN for my two 94 GTS carbs. When pulling the carb on one of the GTSs to check the internal filter, I moved the adjustment for the LSA screw when removing the nut securing the carb to the manifold. I have a manual and reset the screw to the initial setting, checked the idle in the water and set the idle speed to spec and then set the LSA.

My question is how can I determine if I set the adjustment too lean? It does not appear to be running rich and seems smooth, but I wonder if it's set too lean. How can I check/confirm?

Thanks!

Rich

 

[seadoosnipe]

Mixture...

If you set them at 1 to 1 1/4, then you don't have to worry about being lean. At the bottom of this post, there is a link to my "korner". There you will find a page with spark plug pix on what they look like from lean to rich!...:cheers:

 

[RNispiros]

Thanks!

Very informative reference, thanks! I'll back them out a bit as I believe they are at about 3/4 and check them as documented.

Thanks Again!

Rich

 

[RNispiros]

Confirmation - LSA

Well, just checked my original settings and found I set them at 1 turn on one and 1 1/8 on the other. I'll leave that way till the end of the season then start again after i rebuild them both.

Thanks!

Rich

 

[seadoosnipe]

adjustments.........

Both carbs should be adjusted equally.

The low speed settings of the carbs are hard to run lean. It's running lean at wide open throttle that damages an engine. The low speed jets are used from idle to about 1/3 of the way open, then there is a transition period where the both main jet and pilot jet work together, then, your on the main jet at WOT. That's the most important time to read the plugs........

At WOT, run for about 5 minutes, pull the lanyard while the carbs and engine are at max.........then pull the plugs and give them a look see.......:cheers: