Need help diagnosing issue bogging down Monsoon 325

[notaloser]

Hi all,

I’m looking for some help diagnosing an issue with my Monsoon 325. Engine is only 2 years old but I’ve been battling issues with rain water seeping through the cover and considerable corrosion in the engine compartment.

After about 30 minutes from cold start (consistently), upon launch the engine bogs down as I start to get up on plane, and RPMs drop to about 2k - sounds like a deep growl.

I finally poked around today and cleaned all of the spark plug, distributor cap and ignition coil contacts - no corrosion observed. I did find one spark plug cable that does not reliably latch onto the spark plug, and had a friend hold it in place to ensure contact, but the issue still occurred. I’ll be replacing all of the plugs and cables, as it’s time anyway. 
 

After poking around today, the issue occurred on the first launch. 
 

I will post a video shortly - unfortunately you can’t hear the engine noise as well as I had hoped, but oh well. 

Any suggestions?

[Steve B.]

Does it run good during those first 30 minutes?

Steve B.

[Eagleboy99]

Dropping to 2K RPM sounds like limp mode.

[notaloser]

 

[notaloser]

Before today (after I’ve messed around with ignition components) and it lasted 30 min, it ran without issue.

Can you help me understand limp mode? Relevant to CEFI3?

Edited September 26, 2020 by notaloser

[Eagleboy99]

Limp mode could because of... low voltage.  Low fuel.  Bad battery.  Low fuel pressure.  Et cetera...  You need to scan the engine and see if there are stored codes.

[dlb]

Did you change the fuel filters?

Also, what about bad gas or water in the gas?

Edited September 26, 2020 by dlb

[wdr]

A bad oil pressure sensor will induce limp mode also. Mine was running great, then went limp, then ran fine, then wouldnt... This doesnt sound like what I experienced, but who knows with electrical gremlins. As @Eagleboy99 suggests best to pull the codes before you start throwing money at it.

[notaloser]

Thank you, all! Sounds like the next step is to pull codes. I’ve never had any luck finding “official”  documentation on MEFI - Anyone know if service or tech manuals are available?

I did check and change the racor fuel filter first. Could be bad gas, but I buy from a very reliable marina which serves the entire river and haven’t heard of any others having issues. 

[Eagleboy99]

Pretty sure @justgary posted  a MEFI manual.  Search is your friend.

[UWSkier]

No beeps. Does the beeper work on startup? I'd check fuel pressure before digging into the ECM. 

[Nitrousbird]

I'm not sure if there is a limp mode of the CEFI ECU.  

Break  out a few bucks and get the scanner cable from MEFI Burn.  At least you can view sensors before and after the issue and see what has changed.  Should help clue you in to the cause..