I have a 96 Mercury 150xr6. Once air temps are above 80 my motor is hard to start and has trouble idling. I have to open the throttle for the engine to start.Seems to get worse the warmer it is. I appreciate any feedback.

I have a 98 Johnson 150 hp. I have the opposite problem. The colder it gets the tougher it is to start. The only thing that works is to hold the choke down all the way and keep it down, otherwise it will flood. Eventually, after enough choking and winding, it starts up. Once it is warm, no problem. The throttle position seems to make no difference. Obviously it is absolutely necessary to have a well charged battery. I think both motors are female. Only thing I can think of.

Your idle air screws are out of adjustment. Run all in then back out 1/2 turn to start with. Back them all out at 1/8th increments until running right. Bait956 check for correct sparkplugs. Champion only. Try the pump up the bulb, turn key just to on, hold choke in to a count of 10, start it. Some times it is necessary to quickly bump the choke in when it tries to die.

Thanks Gary I appreciate your knowledge.