1976 mercury 1150 motor.<br />while trying to get my motor to idle below 900 rpm I notice that the bottom carb adjustment screw has no affect on the motor. I can screw it all the way in or all of the way out and the motor does not change. If I idle it down to 800 rpm the motor will die. Carb is tight with no leaks. motor runs great at wide open just wont idle down the way it should. any info will be appreciated.
<br /><br />Then One (or combination) of three things is going on here: in order of ease to fix.<br /><br />1. The low speed circuit in the bottom carb is clogged or the float needle is leaky and flooding the bottom 2. Needs cleaning either way.<br /><br />2. The reeds / reed blocks are tired. This 1st shows up as difficult idle. That said the idle needles usually have some effect anyway thus the "combination" answer.<br /><br />3. The bottom end-cap seals are bad and again contributing.<br /><br />If I were you I'd clean the bottom carb and make sure it's OK. Past that, you might wanna live with an idle of 900. Going in to do the reeds gets expensive.<br /><br />-W