200 efi problems. Please help

[Will Seyler]

Serial # OT665171. I am posting this for a friend so I hope I use this forum correctly. Motor is a 200 up efi motor, but it has carburetors. I believe it is a 2003 model. The motor is extremely difficult to start all the time in all weather conditions. Normally this results in the cranking battery going dead and the boat never starting. Also something is draining the cranking battery while the boat is parked. Nothing is staying turned on so I think it could be the power pole. Can't remember what prop he is running but the tach does not work. I will say the motor runs strong when it does actually start. Can someone point me in the right direction before he gives up on this boat? Thanks

[leonreno]

According to the serial number it’s a carb motor. What starting procedure is he using. First, pump the fuel bulb firm. The trim the motor level. Push the key in and hold for 10 seconds (this is the enrichment circuit). Then start the motor. If it doesn’t start right away, then hold button in a few more seconds and try again.

You should also check the fuel lines if they have never been replaced, older lines can deteriorate from the inside due to ethanol. Also, I would recommend cleaning carbs. Also run a check for spark on all cylinders. I have the same motor and mine usually starts on the first or second try if I follow above steps. If it ever gives me a little more trouble then I will open the throttle a little and start it that way, usually on necessary if I flood the motor.

[Will Seyler]

Thanks for the advice. He uses a similar starting procedure. All cylinders have good spark. What cranking battery are you running? Not sure he is running the correct battery. Also forgot to mention that it is easier to start on muffs but not always a guarantee

[leonreno]

I’m using a wet cell marine starting batter, 840 CCA.
I think it’s this one:
https://www.oreillyauto.com/detail/b...y/27ms/4742402
the minimum requirements are far less than that but I think it needs a little more than the minimum. But, you should only use wet cell starting batteries, Mercury states no deep cycle, maintenance free or AGM batteries. It’s bad for the charging system.

Performing a link n sync may also be needed. This makes sure the timing, throttle etc is all set correctly. Best to get a OEM service manual, has the procedure in it, plus about any other trouble shooting procedure.

[ChrisCarsonMarine]

This motor uses a primer to"choke",and you need to see if it works while pushing on the key,Should hear a click,but you will need to be by the motor with the cover off.Sounds like the primer isn't being used,or is not working,Chris

[EuropeanAM]

I would concur with what Chris suggested- need to check the enrichment solenoid, verify it is actuating, test to confirm it's OPENING, and if it is, verify fuel is supplied to the enrichment solenoid.

[leonreno]

Another thing you should check is the regulators, if the tach is not working, it could be caused by a bad regulator. Looked for burnt or melted parts or wires. A bad regulator will cause charging and battery problems.

FYI: the enrichment solenoid is connected to the top carburetor, it’s an electric valve that opens and allows fuel to drain from the top carb bowl into the throats of the bottom two carbs to provided extra fuel for starting. It clicks when the button is put in the on position and pushed in.

[Will Seyler]

Thanks for the help and replies. I can hear the enrichment valve click when the key is pushed in. i'll look into making sure it is functioning properly. Also im almost certain the regulators were replaced around march of this year. what service manual should i purchase?

[leonreno]

The only service manual I would buy is the Mercury one, can be purchased from your local dealer or can order from Don (European Marine), post #6 in this thread, there is a link in his signature to order parts or you can call and order it. It’s easily the best purchase I’ve made for my boat.

[JOE54]

+1

[silvertalon]

I'd look at the Thermal Air Valve located on the Strbd cyl head. It is for enrichment during cold start-up. Be sure the motor is level or tucked under to help fuel gravity feed. Check your intake reed valves for spitback while cranking. You could have a broken reed valve. Also, you can remove the carb cover and try a spray bottle of fuel/oil mix to manually enrich the cylinders. Be sure the spark is strong on all cyls. You are looking for blue/white spark that is snappy and strong while cranking with the plugs installed and battery at full charge. Weak orange/white spark most likely will not fire the plugs and they will be very wet with unburned fuel. , in which you'll need to DVA test the stator for output. Tach-. Swap grey bullet connectors to the other 20A reg/rect and see if the tach works again. A shorted tach will prevent the motor from firing. A regular wet cell battery should reed 13.2 at full charge (2.2V per cell = 13.2). When the motor is running at idle, you should be getting around 14-14.5 V at the battery.

[Merc2.4]

Does the motor run fine at wot? What's wot rpm? Have you lost rpm? Sounds like dirty carbs. Can u post a start and idle video? If have strong spark ,its fuel or compression

[Will Seyler]

Yes it does run fine at wot. I don't know the rpms because the tach doesn't work. The grey wire on the top rectifier is not plugged in and I haven't been able to locate the wire to connect it. I really need a service manual but not sure which one to get. Thanks to everyone for the replies and advice

[leonreno]

To get the right service manual, call or go to your local Mercury dealer with your serial number, and they order the right one for you.