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Does anyone own a 2002 Mercury optimax outboard and are having any problems with the motor cutting out at slow speed and not being able to be restarted. I had a mercury rep look at it and he reprogrammed the computer in it.... Well that didn't work so back to the dealership it goes.
We've got twin 2002 225's on a Boston Whaler. When the engines were new, the port motor stalled out on several occasions while docking (which is no fun). However, we were able to get it restarted. After a couple of visits by the dealership, the port motor worked fine, but then we experienced problems with the starboard motor stalling out in idle. They got that working and the lastest problem was a "fault injector" as the computer read on the dash. New injector and no problems, of course we haven't run the boat much recently, so I'm excited to see what fails next.
Mercury has had a lot of issues regarding the proper computer calibrations on many Optis. My pair of 1999's were hard to cold start. Factory rep changed computers with no success. Problem turned out to be that the air rail pressure was slowly bleeding down because the little schraeder valve wasn't seating properly. Fiddled with the valve stem and all is fine now. If your trained Optimax mechanic ran the DDT scan on your engine and didn't find a trouble code you probably need replacement computers ($800 each out of warranty).Also the rep showed me another trick to get it running. On cold startup you can disconnect the temp sensor wire. The computer richens the fuel mixture and fires right up. The engine will continue to run about 200 rpm's faster than normal at idle until you reconnect the temp sensor wires. Optis are designed to run as lean as possible and incorrectly calibrated computers can make it too lean to run. Plus the air and fuel rail pressures are critical for operation. Optis also have had issues with throttle position sensors.There are two of them (inner and outer). when one fails the engine speed is limited to 3000 RPM and when both fail the engine speed is limited to idle. Are you getting any warning lights and or alarms?
At 1st I got a Speed Comp fault. The dealership reset that. Then it went back for Fault Throttle and Fault Sensor. Now I'm getting no faults at all. I just won't run....
I'll bet that you have problems with the throttle position sensors. What about the instument warning gauge. The check engine light (lower light) should be lit and alarm should be beeping if you have a sensor problem. Optis also need to have a 1000 MCA battery for proper voltage to the ecu. If you can be very specific about you symptoms I will go thru the troubleshooting section of my manual with you. (Engine cranks but no start, engine cranks starts and stalls, rough idle,idles fast or surges up and down, runs rough below 3000 RPM, runs rough above 3000 RPM). Pick a symptom that most describes your problem and I'll see what I can do. These should still be under warranty but not many mechanics (merc guys too) are properly trained on Optis. Maybe we can at least show them where to look.
The symptoms are: I start the motor and let it warm up for 5 minutes or so then I put it into Fwd or reverse. The boat starts to move then it just shuts off. There are no alarms no warning messages nothing. It just shuts off and it won't restart. The mechanic from Mercury re-programmed the computer and that didn't work. The dealership mecahnic checked ann the fuel and air pressures and they are fine. They even ran diagonstics and all sensors check out. I have Smartcraft computer on motor. I called Mercury and they said they have never seen this problem before... I'm very frustrated because I started having problems in the middle of Aug...
Check shift linkage under cowl to see if there is any intereference with wires. In fact make a very thorough inspection of al under cowl wiring. Dont just trust that the mechanic would have seen it. This sounds more like an interupted circuit than anything else, the question is whether it is caused by your moving of the shift linkage or by the vibration of the motor when placed in gear. I have much Opti experience, most of which I diagnose myself. I have a DDT and a service manual and I am dangerous! [img]/infopop/emoticons/icon_biggrin.gif[/img]
Ahoy Jonboater,
Sometimes Opti problems wont show themselves on the DDT. Perhaps it isn't even an engine problem but a bad fuel problem or restricted fuel delivery (anti syphon valve, primer bulb, contaminated fuel, clogged fuel tank pickup). Have you attempted to run the engine on a portable tank with a known good primer bulb and fresh fuel? I would do this first to at least eliminate a potential problem with the fuel tank and plumbing. You may also have fouled spark plugs (they have a history of oil fouling) so clean and regap the plugs too. From past experience however your problem still seems like a mis calibrated ECU or faulty Throttle position sensors.
The service manual describes your symptoms as "Engine cranks, starts and stalls"
The causes for this can be:
1) low air rail pressure
2)low fuel rail pressure
3) high friction in engine
4) air in fuel system or lines
5) TPS malfunction
6) Remote controll to engine harness connection
is poor (inspect and clean connectors)
The wide array of sensors tell the computer how to adjust operations. Any sensor malfunction or disconnected wire can cause problems and some sensor wires are easy to pull loose when installing the cowling. Try the portable tank method and report back to us. One of us Opti gurus should be able to help you.
After discussing this problem with the Consumer Protection Division of Boat US. It sounds like there is a integration problem between the ECM and the motor. I have the dealership that I bought the boat from looking at it now. Hopefully a resolution will come shortly. If it doesn't then I will take action just to protect myself and my investment.
Johnboater,Let us know what you find out.Like I told you in my bmail new plugs corrected my shutting off motors.When yours shut off did you try and pump primer balls to restart.Thats the only way mine would restart.A mech. told me when the motor is not shut off by key is screws something up in computer and thats why Ihad to keep repriming balls.
Good luck.....
When I read any recent post on Outboards-- I am relieved that I use an I/O with a distributor and carb These are easy to work on I will put up with the "hard part" u-joints and boots-- My I/O runs when it is suppose to run and does not eat gas I don't need a tech to make it run-- any person that can read and turn a wrench can keep them running.. Yes it is black and has a orange engine that has been painted BLACK I.E. Chevy small block P.S. All the parts can be found on the floor of any gararge. Once I broke down my water pump when out..My fault.. didn't replace after four years of use.. gave a call on radio.. got a new impeller and replaced the same on the beach.
2002 Mercury Optimax Outboard 
