Merc 175, I messed somethin up.

[jdp8488]

Yesterday I took the boat out. Stopped at a fishing hole, dropped the trolling motor, when I went to restart the merc, it kept stalling. Got it home, fuel was spraying out of the bottom carb. One of the needles on the floats was stuck. Took care of that, ran great, just has a high idle. Idles about 1100 rpm. How do I adjust this, If I put pressure on the plastic bar that connects all three carbs, it will idle fine, I do not know how to get it to permanantly stay like that. Thanks for any help. I didnt mess with anything other than that one float and needle..

 

[CharlieB]

Re: Merc 175, I messed somethin up.

In the process of cleaning that carb you didn't realize that the throttle linkage as NOT exactly as it was.

Even if you didn't change anything on the linkage the carb position may be a few thou off from its last position simply due to the slop in the mounting bolt holes.

You need a service manual and follow the procedure to sync the carbs then link the throttle linkage to the timing linkage, to ensure perfect operation of your motor.

 

[jdp8488]

Re: Merc 175, I messed somethin up.

I got it, when I pulled the carb, I took the pin out last that connects to the plastic bar that syncs all 3 together. I guess it pulled a little bit out, and the butterfly on the bottom carb was slightly opened. We loosened the screw and and popped back into place. Got to water test it to make sure. I still couldnt find any kind of idle adjustment screw. Do these carbs just not have them?

 

[CharlieB]

Re: Merc 175, I messed somethin up.

No idle speed adjustment on the carbs. Idle speed is set by adjusting idle timing.

If you just cleaned carbs you should not have to change it.

Idle air is fixed by the factory drilled hole in the butterfly.

Idle mixture is set at idle IN forward gear while on the water. Adjust to best idle PLUS about 1/16 turn out (richer). If on the hose set to best idle plus 1/4 turn until you can recheck when on the water.

Test adjustment by slamming throttle wide open in forward gear. Any hesitation or bog then readjust idle mixture richer about the width of the screwdriver slot. Retest WOT.