Warning alarm comes on after engines start

[jimrobeson]

Just had my spark plugs changed, impellers and fuel filters. Mechanic asked if I had been having trouble running the port engine as it was running rough for him. Suspected the fuel pump was going out. I go down and try to fire the port engine and had no luck until I gave it a little throttle. After that, engine would fire as normal and idle perfect. Only problem was that I had a warning tone every 4 to 5 seconds. All fluids were normal. I am running 2000 350 Mag MFI with Bravo 3's.

So far all I have found is that I might have a faulty gear lube sensor?? Any help on this would be great!!
Thanks.

 

[Fun Times]

Being a 2000 boat/engine you should have MEFI 3 type ECM. Your engine serial number would help confirm things though.

Since you had to or have to keep giving it some throttle before starting plus having a warning beep might be an indication of a failing engine sensor such as the Idle Air Control Valve, MAP sensor or Engine Coolant sensor, Intake Air Temp sensor.

Top off the drive gear lube bottle to see if it helps stop the horn...If not you'll either want to get ahold of a marine scan tool to see if there are any engine codes from the sensors or if you do really have the MEFI type ECM then you could try the following method of a few others to see if a code number pops up..., https://www.youtube.com/watch?v=fSEwwa6D2jM

If the flame arrestor cover is dirty it would give you hard starts. Could try cleaning the throttle body unit and flame arrestor.

 

[alldodge]

warning tone every 4 to 5 seconds

That would be new for a MEFI or even 555, but agree with a 2000 it should be a M3. Serial number would help.

 

[jimrobeson]

Being a 2000 boat/engine you should have MEFI 3 type ECM. Your engine serial number would help confirm things though.

Since you had to or have to keep giving it some throttle before starting plus having a warning beep might be an indication of a failing engine sensor such as the Idle Air Control Valve, MAP sensor or Engine Coolant sensor, Intake Air Temp sensor.

Top off the drive gear lube bottle to see if it helps stop the horn...If not you'll either want to get ahold of a marine scan tool to see if there are any engine codes from the sensors or if you do really have the MEFI type ECM then you could try the following method of a few others to see if a code number pops up..., https://www.youtube.com/watch?v=fSEwwa6D2jM

If the flame arrestor cover is dirty it would give you hard starts. Could try cleaning the throttle body unit and flame arrestor.

Serial number OL363522
Top off gear lube and once I got the engine started never had to give it throttle again. Kind of confusing that I needed to give it throttle to get it to start? Everything you mentioned I have read on the internet so you are spot on. I'm going to have the guy that worked on it check the engine with his computer.

Thank you very much for the advice.

 

[alldodge]

The S/N comes up as a MEFI-1 so should have very few things to alarm and all would be solid. Suggest disconnecting one of the leads to the lube bottle. If this stops the beep then need to clean the bottle

 

[jimrobeson]

The S/N comes up as a MEFI-1 so should have very few things to alarm and all would be solid. Suggest disconnecting one of the leads to the lube bottle. If this stops the beep then need to clean the bottle

Thanks!! I will give that a try. I'm hoping it's not a serious thing. This has been a great boat and up until now haven't had any troubles. 2000 Larson 330 Cabrio. Just a little over 500 hours.

 

[Fun Times]

Yes looks like a MEFI 3 ECM using your serial number, https://www.mercruiserparts.com/bam/subassembly/31746/4848/60

A lot sort of happens when you have to give it throttle to help start the engine on an EFI engine.

One would be the engine needed more air to help bypass the IAC valve due to maybe being stuck or shut off in the wrong position to where the IAC isn't able to work correctly and if the IAC is old/dirty; 'it's going to be moving much slower and can't keep up....Or say if the engine was running to rich and flooding out while cranking the engine over while having a bad reading engine sensor, once you hit a certain percentage of the throttle movement, (which varies on each engine model) the ECM enters a clear flood stage which is designed to shut off the fuel injector pulse width while cranking giving your spark plugs a chance to dry out of too much fuel.

So your event might be a one time thing due to the IAC in an odd position which happens from time to time or it could be a sign of more issues to come and a good cleaning of the air intake system is a good place to start....But that mentioned if the warning horn is still sounding then yes you need to stay on the path of why that is with a scanner or the video posted.

Also now that I think about it I do believe your engine model may have the Low Fuel Pressure Sensor which not all engine models had/used in-turn would sound the warning horn too and create a hard start if low...Yes I see it in your parts guide as item number 14, https://www.mercruiserparts.com/bam/subassembly/31746/4848/120

Since you just had your fuel filters changed you may have had some air in the fuel rail system which sounded the warning horn and making the engine hard to start for the first time or so ?.

 

[alldodge]

Looks like punching in the s/n in BAN doesn't always bring up the correct configuration. You do have a M3 and not a M1 as FT mentioned.

The one beep/tone every 4 to 5 seconds still does not equate to a M3

Will be interesting to find out what the issue is

 

[jimrobeson]

Looks like punching in the s/n in BAN doesn't always bring up the correct configuration. You do have a M3 and not a M1 as FT mentioned.

The one beep/tone every 4 to 5 seconds still does not equate to a M3

Will be interesting to find out what the issue is

Really appreciate all the info. I will definitely post what the outcome was. Especially when at first the guys working on her first thought I had a fuel pump issue. I never once had any sign that I was having a fuel pump issue. She would start every time, all the time. But I do know that things can go sideways most anytime .

 

[achris]

Easiest way to clear up all confusion. Here's a picture of each of the ECUs. Which one do you have?

 

[jimrobeson]

Easiest way to clear up all confusion. Here's a picture of each of the ECUs. Which one do you have?

Not sure. Will have to check when at the boat the next time.

 

[alldodge]

No issue, FT had it correct, no confusion, all of it was on my end