Stalls and surges 350 mag mercruiser mpi

[ChipR]

I have a 2004 crownline 202lpx with the 350 mag mpi, been having issues when coming off of plane to a slow idle it will run great but when I try to shift to neutral it will start to surge and not come out of gear and die, I restarted the boat and it’s in neutral and idils high at about 1k rpm but hole shot and driving on plane it’s runs flawless. When I first put boat in the water it will run great but after it gets warm isnwhen this happens Any suggestions?

 

[alldodge]

idils high at about 1k rpm

I'm assuming you have an Alpha drive and if so idling at 1K is to high (even to high for Bravo). When shifting to neutral the shift interrupter signals the ECM to misfire so the clutch in the drive will unload. Being at a high idle, this will be an issue.

Idle needs to be at 600 rpm for this to work correctly

What is the motor serial number?

 

[ChipR]

Yes I have a alpha drive. When it is first put in the water it idles right at 6-800 rpm and wholeshot and driving it’s great. Just only when slowing down to trolling speed to neutral it was surge and when I try to rev it up in neutral, it’ll still be in gear until it dies so once I start it back it’s in neutral again I’ll get the serial number when I get home

 

[alldodge]

Could use a scanner to see if there are any codes, but I thinking about the IAC

Might just need cleaning

 

[ChipR]

The serial number is OM667448. Will this help any?

 

[alldodge]

Serial number helps, thanks
I woul remove and look at item 16 (IAC)
Use some soap and water, and soft brush

https://www.mercruiserparts.com/bam/subassembly/31748/8093/85

Also remove and clean IAC muffler item 6 with same soap and water

 

[ChipR]

I just took mine apart and noticed I do NOT have the item #6 in mine..... is that the muffler part tissue "square piece"? Do you have to have that?

 

[alldodge]

Its best to have it because it keeps larger pieces of crud from getting stuck, or clogged in the valve. It could be that since its gone, this could be why (if it is sticking) for the trouble

 

[ChipR]

Okay. Thank ya. Gonna get it and see if it’ll work