my 18 hp merc wouldn't idle without stalling. It ran rough and used up too much gas. I adjusted the idle screws but there was only 1 screw. is there only supposed to be 1? also, it didn't want to start while in idle after i adjusted the screw. it idled when i adjusted it, but if i killed it and tried to restart it it wouldn't stay started. i had to start it at full throttle. is it just a matter of getting the settings right or is there a larger prob. i already changed the plugs.
