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2004 230 5L MPI Engine shows Check Engine Alarm

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robflyn

New member
I have been reading this forum for a while and see there is a lot of experience here. need some advice
i have a 2004 searay 230 with 260hp 5 MFI engine with 200 hours. purred like a kitten until last Tuesday. First time able to run it at 4500 rpm (36mph) on light seas for about 10 min -then *alarm buzzer & check eng *appeared on smartcraft screen. - temp got up to 165F, then idled & cooled to 140F & was able to go slow 20 min to home with alarm going off every 2 min.**
went out today -*Saturday (after non hurricane). same problems!*now it*won’t start unless i release shifter and advance thorttle to 1500+rpm. temp is 135, oil press 50, volts 14.2 volts. *belt is tight. no loose wires.
also now it idles rough at 1500 smooths out at 2000. *stalls in netural at idle. check engine warning appears with alarm buzzer.* What could cause this?* I rebuild sports car engines but this is my first I/O.**Thanks.
only got to put 30 hours on it this year really want to use it the next couple weeks.
some background - I just bought it late July, was in water last year used only a*couple of times - then owner had it tuned up and winterized. when i bought it still had barnacles covering lower unit & stainless prop - could these also have grown in engine blocking cooling system?
 
Re: 5L MPI Engine shows Check Engine Alarm

...could these also have grown in engine blocking cooling system?
Click to expand...

Quite possible to have them blocking the seawater inlet. Seawater pump impeller may be failing. Barnacles on the prop can put it out of balance and cause the vibration.

*stalls in netural at idle.
Click to expand...

Dirty IAC (Idle Air Control). Bad gas--water in the tank and/or dirty throttlebody and/or injectors.
 
Re: 5L MPI Engine shows Check Engine Alarm

guyjg thanks
i sanded off all barnicles before launching this vyear and painted lower unit with anti fowling paint.
took iac off - couldnt see internal valve. read it is a stepping motor driving a needle valve in and out so i sprayed wd40 into it to clean it out and rapped it incase it was hung up then reinstalled. engine idled back down to 500 rpm! Thanks! it surges now between 480 to 540 rpm. could it be a bad iac? is there a way to test iac? could it be a vacuum leak? oil pressure is 50+. temp holds at 158F. i assume its a 160 tstat. do you have a manual is this the right Tstat? i read some where else that some of these engines used 140F Tstats. Alsp Engine guard continues to to buzz "check engine" every 2 min. does this reset itself or is there a switch? Thanks again.
 
Re: 5L MPI Engine shows Check Engine Alarm

probably IAC is bad, thats what the intermittent alarm is telling you,most 5.0's are 160-170 temp that I have seen.
 
Re: 5L MPI Engine shows Check Engine Alarm

I don't have a manual. Listen to gl115 and replace the IAC. Clean cavity with Throttle Body Cleaner; don't use Carb cleaner.
 
Re: 5L MPI Engine shows Check Engine Alarm

It was the IAC! unsuccessfully tried to free up actuator in original. replaced IAC and it ran great! local mercrusier tech says he would keep a spare on hand - replaces lots of these. throttle body looked new, replaced breatheer filter under flame arrester. Guardien alarm reset by itself with new parts. Thanks for the help!
 
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