Help!! 2004 Mercury 60 HP 4 Stroke EFI very fast idle

[jerseyljn]

I have a 2004 mercury 60 hp 4 stroke EFI outboard. Engine was fully serviced, tuned, and run up before storing for the winter. Dropped the boat in over the weekend and immediately experienced a major issue that has never happened before. The engine is idling somewhere between 2800-3200 rpm, and occasionally drops down to about 1500 runs rough for a split second then cranks back up to the range listed above. I was able to get the boat in gear, and it is trolling very fast (2000 rpm), and runs fine at WOT. I have eliminated all of the basics and beleive that it is one of the sensors or the IAC. I do not have a merc computer reader and would like to see if anyone has experienced a similar issue or could offer some advice on how to troubleshoot the IAC, TPS, or other sensors that it might be. I am feeling like the issue is the TPS but I would rather not just start replacing things.

Thanks!

 

[jerseyljn]

Re: Help!! 2004 Mercury 60 HP 4 Stroke EFI very fast idle

I have a 2004 mercury 60 hp 4 stroke EFI outboard. Engine was fully serviced, tuned, and run up before storing for the winter. Dropped the boat in over the weekend and immediately experienced a major issue that has never happened before. The engine is idling somewhere between 2800-3200 rpm, and occasionally drops down to about 1500 runs rough for a split second then cranks back up to the range listed above. I was able to get the boat in gear, and it is trolling very fast (2000 rpm), and runs fine at WOT. I have eliminated all of the basics and beleive that it is one of the sensors or the IAC. I do not have a merc computer reader and would like to see if anyone has experienced a similar issue or could offer some advice on how to troubleshoot the IAC, TPS, or other sensors that it might be. I am feeling like the issue is the TPS but I would rather not just start replacing things.

Thanks!

Bump. 99 views and no one has any advice? Thanks!!

 

[Jeep Man]

Re: Help!! 2004 Mercury 60 HP 4 Stroke EFI very fast idle

I have a 2004 mercury 60 hp 4 stroke EFI outboard. Engine was fully serviced, tuned, and run up before storing for the winter. Dropped the boat in over the weekend and immediately experienced a major issue that has never happened before. The engine is idling somewhere between 2800-3200 rpm, and occasionally drops down to about 1500 runs rough for a split second then cranks back up to the range listed above. I was able to get the boat in gear, and it is trolling very fast (2000 rpm), and runs fine at WOT. I have eliminated all of the basics and beleive that it is one of the sensors or the IAC. I do not have a merc computer reader and would like to see if anyone has experienced a similar issue or could offer some advice on how to troubleshoot the IAC, TPS, or other sensors that it might be. I am feeling like the issue is the TPS but I would rather not just start replacing things.

Thanks!

Had a similar situation with mine ('02 efi 60 hp after being serviced. Turned out to be the throttle / shift cable connections. Maybe a stupid question, but have you checked to see if the problem is still there with the cables unhooked.

 

[tazrig]

Re: Help!! 2004 Mercury 60 HP 4 Stroke EFI very fast idle

I do not have a merc computer reader

Can you even get one? I was told that unlike cars where you can just get an ODB-2 code reader, Merc's software is all proprietary so only they have the readers and will only sell them to the dealers.

 

[steven b g]

Re: Help!! 2004 Mercury 60 HP 4 Stroke EFI very fast idle

i have a 2006 mercury 60hp efi 4-stroke doing the same thing and i'm curious if you ever found out what was the problem?

 

[jerseyljn]

Re: Help!! 2004 Mercury 60 HP 4 Stroke EFI very fast idle

i have a 2006 mercury 60hp efi 4-stroke doing the same thing and i'm curious if you ever found out what was the problem?

Hi Steven - yes I figured it out - responded to your pm with more details. It was a vaccum line that fell off from the IAC. Let me know if you figure it out.

Lucas

 

[SwampAngler]

Re: Help!! 2004 Mercury 60 HP 4 Stroke EFI very fast idle



Hi Steven - yes I figured it out - responded to your pm with more details. It was a vaccum line that fell off from the IAC. Let me know if you figure it out.

Lucas

Hi Lucas, wanted to let you know that even nine years after your original post, the problem is still happening and your solution is still helping. I have a 2019 Mercury 50 HP that suddenly had a very fast idle after starting. Had visions of having to haul it to the dealer, being without the boat for weeks while problem was diagnosed and fixed, and spending Big Bucks. Then I came upon your post. Sounded like it was worth a try. Searched under the cowling. Found separated rubber hose section and plastic tube. Plugged the tube into the hose and, VIOLA, idle back to normal. Thank you so much for sharing your solution.
Bruce