04 Merc 115 hp 4 stroke efi idling problem

jherm

Recruit
Joined
Oct 2, 2009
Messages
2
My motor will not idle the last few times I have run it. It starts fine and will idle for about 20 seconds, then die. I can start it back up with no problems and once I quickly push the throttle to get the rpm's up a little bit, the motor runs just fine. When I go back down to very low rpm's or idling, the motor stalls out. I replaced the spark plugs when this came up and have always winterized it with fuel stabilizer, fresh oil, etc. I recently put a cleaner in my gas and have run the boat at about 2200 rpm's for 30 minutes, but that doesn't seem to have helped. Any ideas of what I can try?
 

sdsaw

Petty Officer 2nd Class
Joined
Aug 19, 2007
Messages
188
Re: 04 Merc 115 hp 4 stroke efi idling problem

Try cleaning the idle air control valve with some carb cleaner
I'm not sure if Mercury was still using the Yamaha powerhead in 2004, but here is a picture of my 2001 IAC valve that I've had to clean every now and then when I start having idling issues

IdleAirControlValve.jpg


It's the round thing and you will have to pull a few hoses, the connector and remove the screws to lift it out.
I shoot the cleaner on the tip and let it soak a bit and the blow it out with compressed air
 

jherm

Recruit
Joined
Oct 2, 2009
Messages
2
Re: 04 Merc 115 hp 4 stroke efi idling problem

Thanks. I tried your suggestion but it did not work. Brought it into the dealer last week (after winter storage) and you were right - it was the idle air control valve. However, it was shot so that is why just cleaning it didn't work. Had it replaced - along with some throttle adjustment - and it runs great.

Also, I changed my spark plugs in mid '09 thinking that might have been causing the problem. I had them in for only 25 hours of engine run time and they were already shot when the mechanic looked at them. The mechanic that worked on it (very good friend of mine from high school) said that happens when these idle air control valves are either dirty/plugged or are not working properly. Just another something to look for if anyone is having similar problems......

Thanks for the direction Sdsaw. If the valve had only been dirty, your suggestion would have had me up and running.
 

Sunsetjerry

Cadet
Joined
Nov 29, 2021
Messages
14
where is the IAC valve is on a

Mercury 2003 115 4-strokeEFI​

 

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