MerCruiser 350 MAG MPI beeps 3 or 4 times then dies.

I have 2000 MerCruiser 350 MAG MPI in my Crownline. It has been a great boat so far except just this week we had to get towed in twice. Anyways both times same thing, we unload just fine, run around for about a half hour, then sit for an hour, then run around for another half hour, then sit for another hour. Then go to start it up and I get 3 or 4 beeps after it turns over then the engine dies. I thought maybe it was a bad fuel gauge (even though it read half full) so I put 20 more gallons in it, put the ear muffs on and it started right up and ran fine for 10-15 min.

Symptoms:

Boat starts up fine and will run for a while.
3-4 beeps at idle then shuts off.
1st attempt to restart and it will idle for 10-15 seconds. When you put the throttle into neutral and give it some gas you can hear it back firing or feeding back. (no beeps)
Repeat attempts to start it and it won't run for more than a couple seconds. (no beeps)
You can hear the fuel pump kicking in so I don't think its that.
All fluid levels are full.
Temp runs 130-150.
Kill switch is not engaged.

I have done some reading and I am not getting the 2 beeps every minute. I have read that it could be a bad sensor, maybe IAC or the IAC valve muffler is clogged, maybe timing?.?...

Anyways I'll most likely be taking it into the shop for a look here shortly but I wanted to see if I am missing anything.

Thanks much in advance.

Tony

Re: MerCruiser 350 MAG MPI beeps 3 or 4 times then dies.

Tony:
I don't have the experience to help much with your problem and it might not be related but if you saying with the engine warmed up the temp is between 130-150, then that's too cold for a warmed up mpi engine.

You don't say whether it's rwc or fresh water cooled but most rwc mpi engines should run in the 170ish range when warmed up and operating properly. Both my 2001 7.4 mpi and 2005 4.3 mpi run in the 170-175 range when warmed up.

Maybe with a IR temp gun you can verify that actual temperature and determine if that is really the temperature or a gauge not reading correctly.

Mark

Re: MerCruiser 350 MAG MPI beeps 3 or 4 times then dies.

Tony1474 said:

3 or 4 beeps

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I'm familiar with 2-beeps at startup, if you get only 2 beeps and all your gauges are within normal ranges it is likely your IAC valve. I have experienced that twice now. Simple fix, approx $100 in parts and 10 minutes to install.

Re: MerCruiser 350 MAG MPI beeps 3 or 4 times then dies.

What you need to do FIRST, before you start throwing expensive parts at the engine, is get a diagnostic computer or a scan tool hooked up... Yes it sounds like a sensor is failing, but without looking up the fault codes EVERYONE is just guessing.... and asking YOU to put your hand in your pocket! It could also be as simple (and inexpensive) as a failing/faulty relay, but without the scan tool.... ???

Chris...

Re: MerCruiser 350 MAG MPI beeps 3 or 4 times then dies.

achris said:

What you need to do FIRST, before you start throwing expensive parts at the engine, is get a diagnostic computer or a scan tool hooked up... Yes it sounds like a sensor is failing, but without looking up the fault codes EVERYONE is just guessing.... and asking YOU to put your hand in your pocket! It could also be as simple (and inexpensive) as a failing/faulty relay, but without the scan tool.... ???

Chris...

Click to expand...

True indeed. Can you recommend a good one that I won't have to take out a loan for

Thanks

Tony

Re: MerCruiser 350 MAG MPI beeps 3 or 4 times then dies.

Here's my exact verbiage from another post a couple hours ago for the Rinda hand scan tool I bought:

Plan on boating for several years to come? Plan on doing some of your own troubleshooting repairs? Want to be the guy with the "special" tool that others want to hook-up with to help them diagnose their beep codes and hopefully they will kick in a few bucks or goodies for use of the tool?

Best $400 l ever spent.....and the 1 time I have used it so far would have cost me probably between $150-$200 had I needed to take it to a shop, do the diags then have them replace the part at retail that I was able to buy through the Internet. Already about 1/3 paid for.

Note that there are some $40 adapters depending on your exact year so read through carefully or just give them a call.

Mark