Re: 1974 Mercury 115hp 6 cylinder running rough
They may have disturbed the throttle setting when they installed new control cables, or got the adjustment wrong. You do have to remove the throttle cable from the motor in order to get at the shift cable for replacement.<br /><br />Your motor should have a belt-driven distibutor on it. There are 3 screws on the front of the distributor, on a plate which is attached to the dist. with 2 bolts.<br /><br />One of the 3 screws says "idle stop" or words to that effect. This is the adjustment for idle speed. Don't touch the other 2 screws, one is the throttle stop and the other is for spark advance or "timing stop".<br /><br />If you loosen the locknut on the idle stop and turn the adjusting screw in (clockwise), it'll increase the idle speed.<br /><br />Note that after you adjust idle speed up or down, you may have to adjust the throttle cable for the correct amount of slack in the cable. When adjusted properly, the throttle cable should just barely push the distributor into the idle stop when the control lever is in neutral. You should be able to pull up on the fast idle lever then return to the stop when you put the lever down.<br /><br />You may also need to adjust the idle mixture on the carbs in the water, 1-1/2 to 1-3/4 turns out (ccw) from fully seated on the idle mix screws is a good place to start. Adjust for best idle quality, warmed up and in gear. If the motor bogs when taking off, richen (ccw) each screw 1/8 turn then try again.<br /><br />A compression check might be in order just to make sure everything's OK inside. And check the discussions about decarbonizing, Seafoam sometimes works wonders in that area. I'd run it thru the fuel system also, it could help.<br /><br />BTW, any self-respecting repair shop worth its salt would check the idle speed and shift action in a test tank after replacing control cables. I don't think I'd have them do any more work. Get a Seloc manual and you'll be able to do it yourself.<br /><br />HTH and Good Luck..............ed
