Reply
 
Thread Tools Search this Thread Display Modes
 
Old 07-26-2009, 10:53 PM   #1
Lt. JG
 
Join Date: Apr 2009
Location: Loch Lomond Scotland
Posts: 31
Default Intermitant Fault with mag 350 MPI

Hi & Help, bought 1st boat couple of months ago, Maxum 2700SCR (2003) only 60 hrs on engine, been fun up to a few weeks ago, now 74 hrs on engine

Problems-
1) Notice leaving marina at idle engine missed a beat every now and again, put on plane @ 3500 revs and seemed fine, out for a hour or so returning on plane felt it miss again, came into marina and ticked over fine
2) Went out from marina and the odd miss again, just onto plane @ 4000 revs when dies, heavy smell of fuel, tried to start would occasionally fire but then splutter to a halt, towed home, back at marina fired up and ran for 15 mins at idle no problem
3) Replaced fuel/water separator filter, on draining fuel from old filter it was very dirty – no water, changed inline fuel filter as well and again really dirty from inlet side, took boat out and tested for an hour ok at all revs, thought problem fixed
3) Went out for weekend, no issues at 1000-2000 revs to destination, stayed the night, next day headed for supplies, all well for 30 mins while waiting to dock spluttered to a halt again, wouldn’t start, 1 hour later got started, running really rough, using high revs to keep running sounded like missing on a few cylinders starting and stopping then all ok, limped back to destination between 700-1000 revs never missed a beat, fired up a couple of time during the night all well, fired up in morning for 30 mins before heading home again all well, loaded up kicked in reverse and spluttered to a halt, tried over an hour to start, would occasionally start but splutter and die, towed home again
4) After being towed back tried to start at marina and wouldn’t so hey hopefully find the problem now, an engineer looked at it and she still would not start, he checked fuel pressure - ok, removed plugs pretty dirty so cleaned and re-gapped - engine now fires up but would shut down after anything from 30 seconds to 2-3 minutes, purring away then just shut off as if you switched the key off, then he phoned back to say engine now running for last 15 mins and not shutting off- arghhh
5) Decided to get Mercruiser dealer to run diagnostic test, he did with no fault codes or issues, he checked the fuel pick up wasn’t blocked says engine running away with no faults and seems to be fine, thinks sea trials required to find fault or breakdown again etc
6) Was down last night, ran engine myself for 20 mins revving etc and purring away nicely – so frustrating

Sorry for the long story but I have lost all faith in her and had the embarrassment to be towed in twice now from the same park rangers, there is clearly something not right and I guess the more information the better so any ideas guys??
__________________

gentlemanglobetrotter is offline   Reply With Quote
Old 07-26-2009, 11:55 PM   #2
Admiral

 
seapuppy's Avatar
 
Join Date: Nov 2005
Location: Everett Wa
Posts: 4,681
Default Re: Intermitant Fault with mag 350 MPI

well..more data would help....what sized engine and is it carbed or mpi??....might be either a filthy carb from the statement on filters....or an intermittent bad coil.........but that's only a guess since I'm not there to hear it miss or die..........


welcome to the zoo by the way..

SP :hello:
__________________

__________________
Don't compare your life to others. You have no idea what their journey is all about.
------------------------
SSN683 Association member
Par Excellence
------------------------------
2008 Bayliner 340 - "Wild Whim"
--------------------------------------
I live in my own little world....but it's okay-they know me here!!!

Avid practitioner of the martial art: KLIK-PAO.
Tap-Rack-Bang

Anyone that sez "Size doesn't matter" has never owned a boat!
seapuppy is offline   Reply With Quote
Old 07-27-2009, 08:42 PM   #3
Lt. JG
 
Join Date: Apr 2009
Location: Loch Lomond Scotland
Posts: 31
Default Re: Intermitant Fault with mag 350 MPI

Quote:
Originally Posted by seapuppy
well..more data would help....what sized engine and is it carbed or mpi??....might be either a filthy carb from the statement on filters....or an intermittent bad coil.........but that's only a guess since I'm not there to hear it miss or die..........


welcome to the zoo by the way..

SP :hello:
Hi i was thinking there was a clue in the subject header "Re: Intermitant Fault with mag 350 MPI" lol
gentlemanglobetrotter is offline   Reply With Quote
Old 07-27-2009, 09:55 PM   #4
Admiral

 
seapuppy's Avatar
 
Join Date: Nov 2005
Location: Everett Wa
Posts: 4,681
Default Re: Intermitant Fault with mag 350 MPI

DOH!!...i should try and get some caffiene in the morning before I answer these things....dang......



SP
__________________
Don't compare your life to others. You have no idea what their journey is all about.
------------------------
SSN683 Association member
Par Excellence
------------------------------
2008 Bayliner 340 - "Wild Whim"
--------------------------------------
I live in my own little world....but it's okay-they know me here!!!

Avid practitioner of the martial art: KLIK-PAO.
Tap-Rack-Bang

Anyone that sez "Size doesn't matter" has never owned a boat!
seapuppy is offline   Reply With Quote
Old 07-28-2009, 12:56 PM   #5
Admiral

 
seapuppy's Avatar
 
Join Date: Nov 2005
Location: Everett Wa
Posts: 4,681
Default Re: Intermitant Fault with mag 350 MPI

man..that just sounds strange.....so...places to check in my mind..since no codes showed up.....check the huge plug that connects the engine to the harness....check all connections to the module and computer....make sure they are tight...check the connections to the interrupter switch....then check the connector to the throttle assembly....then there's the switches that your lanyard connects too to shut the engine off..this is an electrical problem and about the only way to find it is to trace everything down.....sorry can't point a finger at it..but these are a real pain..
someone else hopefully will toss a few ideas in here...


SP :hello:
__________________
Don't compare your life to others. You have no idea what their journey is all about.
------------------------
SSN683 Association member
Par Excellence
------------------------------
2008 Bayliner 340 - "Wild Whim"
--------------------------------------
I live in my own little world....but it's okay-they know me here!!!

Avid practitioner of the martial art: KLIK-PAO.
Tap-Rack-Bang

Anyone that sez "Size doesn't matter" has never owned a boat!
seapuppy is offline   Reply With Quote
Old 07-28-2009, 01:16 PM   #6
Lt. JG
 
Join Date: Apr 2009
Location: Loch Lomond Scotland
Posts: 31
Default Re: Intermitant Fault with mag 350 MPI

Quote:
Originally Posted by seapuppy
man..that just sounds strange.....so...places to check in my mind..since no codes showed up.....check the huge plug that connects the engine to the harness....check all connections to the module and computer....make sure they are tight...check the connections to the interrupter switch....then check the connector to the throttle assembly....then there's the switches that your lanyard connects too to shut the engine off..this is an electrical problem and about the only way to find it is to trace everything down.....sorry can't point a finger at it..but these are a real pain..
someone else hopefully will toss a few ideas in here...


SP :hello:
Hi SP, yes going to have to go over them all with a fine tooth comb, i had a guy on the boat doing a tonage meaurement to do with registering with the shipping act etc, anyway i never met him, his wife phoned asking for access to the boat, she mentioned without keys as long as he could get access to the engine which of course he could, funny problems started after his visit, thinking did he accidently knock a cable or something while he was down there in the engine bay - possible i guess, will keep you posted
gentlemanglobetrotter is offline   Reply With Quote
Old 08-11-2009, 09:30 PM   #7
Lt. JG
 
Join Date: Apr 2009
Location: Loch Lomond Scotland
Posts: 31
Default Re: Intermitant Fault with mag 350 MPI

Update - Had the boat out all weekend on the plane giving it plenty, would appear the gremlins have disappeared for now anyway
gentlemanglobetrotter is offline   Reply With Quote
Old 08-11-2009, 09:52 PM   #8
Admiral

 
seapuppy's Avatar
 
Join Date: Nov 2005
Location: Everett Wa
Posts: 4,681
Default Re: Intermitant Fault with mag 350 MPI

well..that's great news....any idea what changed??...


SP irate:
__________________
Don't compare your life to others. You have no idea what their journey is all about.
------------------------
SSN683 Association member
Par Excellence
------------------------------
2008 Bayliner 340 - "Wild Whim"
--------------------------------------
I live in my own little world....but it's okay-they know me here!!!

Avid practitioner of the martial art: KLIK-PAO.
Tap-Rack-Bang

Anyone that sez "Size doesn't matter" has never owned a boat!
seapuppy is offline   Reply With Quote
Old 08-17-2009, 08:12 PM   #9
Ensign
 
Join Date: Aug 2009
Posts: 1
Default Re: Intermitant Fault with mag 350 MPI

Hi

I have had a similar problem with one of mine 350 MAG MPIs - It was the fuel pressure regulator - wich regulates the fuel pressure and also increases it when vaccum in carb. increases.

Sometimes the engine ran great... but sometimes it smelled a lot of fuel and black smoke, when idleing for a while it died... and was very hard to start. I had to clean the spark plugs... and held the cable from the ignition coil ~aprox. 1 cm above distributor(use gloves and keep your hand high up on the cable fram the dist.

You should also check the vaccum cable when engine running for leaking fuel...

I changed the pressure regulator.. and it ran great - you should also be able to identify this fault by using a fuel pressure meter.. on the rail.

As the fuel pressure regulator is fully passive it won´t show up any fault codes.

Good luck!
Cobalt293 is offline   Reply With Quote
Old 08-17-2009, 08:57 PM   #10
Lt. JG
 
Join Date: Apr 2009
Location: Loch Lomond Scotland
Posts: 31
Default Re: Intermitant Fault with mag 350 MPI

Quote:
Originally Posted by seapuppy
well..that's great news....any idea what changed??...


SP irate:
Still convinced it was dirt in the fuel lines, think maybe its finally been fired through, in reality the only two things that were done were inline fuel filter & water seperator/fuel filter were replaced and the plugs were removed, cleaned and re-gapped
gentlemanglobetrotter is offline   Reply With Quote
Old 08-17-2009, 08:59 PM   #11
Lt. JG
 
Join Date: Apr 2009
Location: Loch Lomond Scotland
Posts: 31
Default Re: Intermitant Fault with mag 350 MPI

Quote:
Originally Posted by Cobalt293
Hi

I have had a similar problem with one of mine 350 MAG MPIs - It was the fuel pressure regulator - wich regulates the fuel pressure and also increases it when vaccum in carb. increases.

Sometimes the engine ran great... but sometimes it smelled a lot of fuel and black smoke, when idleing for a while it died... and was very hard to start. I had to clean the spark plugs... and held the cable from the ignition coil ~aprox. 1 cm above distributor(use gloves and keep your hand high up on the cable fram the dist.

You should also check the vaccum cable when engine running for leaking fuel...

I changed the pressure regulator.. and it ran great - you should also be able to identify this fault by using a fuel pressure meter.. on the rail.

As the fuel pressure regulator is fully passive it won´t show up any fault codes.

Good luck!
Hi,

I had a fuel pressure gauge on to check pressure all seemed ok, and def no fuel leaks in or arround the engine, but i'll keep it in mind if the gremlins reappear, cheers
gentlemanglobetrotter is offline   Reply With Quote
Old 08-26-2009, 12:38 PM   #12
Ensign
 
Join Date: Aug 2009
Posts: 1
Default Re: Intermitant Fault with mag 350 MPI

I've been having the same problem all summer. I have the same motor in my boat. I had a mechanic tell me it was fouling cylinders and arcing off of the block. I did some routine maintenance on the ignition system as it is ten years old now, replaced plugs, wires, cap, rotor, ignition sensor, but it didn't work. I am now looking at the fuel system. I checked the fuel pressure last night and it read 23psi, is this proper?
rteebo is offline   Reply With Quote
Old 08-26-2009, 09:14 PM   #13
Ensign
 
Join Date: Aug 2009
Posts: 14
Default Re: Intermitant Fault with mag 350 MPI

mine would do it too. 5-10 minutes and then she'd begin sputtering and crap out on me. 1/2 later, she'd run again.
found it late at night when running it in the driveway... when it started to sputter, i could see little blue lightning bolts under the engine cover...
the coil tower was cracked allowing it to arc to the secondary wire..... killing the ignition. when the coil cooled, the crack shrunk and she'd be fine until hot again..

$54 coil and all is well.
__________________
2001 2300sb. 350 efi bravo3 with docking assist
Dodgezilla04 is offline   Reply With Quote
Old 06-27-2010, 01:35 PM   #14
Lt. JG
 
Join Date: Apr 2009
Location: Loch Lomond Scotland
Posts: 31
Default Still issues

Hi all, well nearly a year down the line and still have this intermittent problem just back of the water today where I went out and ran at 1500rpm for approx 1 hour then as I approached a jetty for docking down to 700rpm she stalled.

Fired up 1st time and headed away from jetty, 5 minutes later started to splutter I was at 2000rpm where she would cut out down to 1200rpm then re spark back to 2000rpm did this a few times then finally chucked it

Got her started again and decided to gun it home got onto plane then she spluttered a little so I came of plane, waited 1 min then put back on plane and headed home without another blip even had her at 5500 WOT

Some history since my last post I have had another engineer look at her with all the up to date diagnostic gear where he connected up the laptop but still showing no fault codes, when he was looking at her she would not fire up so he traced this to the distributor which we removed and cleaned although I suspect when he was not getting a spark at the plugs this was because it was not sparking from the coil but as its intermittent when he then tested the coil it seemed ok, I mention this as the weeks have passed I have broken down a few times and when I try to start her and she just cranks over and does not fire I have proved 3-4 times that I do not have a spark coming from the coil when cranking over

So having seen no spark from the coil I decided either the coil or module was away so in rip off Britain I paid 220 for a new coil and module thinking at last I have fixed this and it was probably a dodgy ignition module but you cant buy them separately over here as I said rip off Britain

Unfortunately when I went down under the hood and removed the ht lead from the coil on the distributor connection to check for a spark today there was hence she fired up so next up is the ecu/ecm???

My local mercruiser dealer thankfully has a spare 350mag now with a cracked block so I have access to all the electrical bits and pieces.

As I have seen the no spark from the coil side what else can cause this I mean what all is in the electrical circuit to check or replace that can intermittently stop the coil from sparking, arghhhhhhh
gentlemanglobetrotter is offline   Reply With Quote
Old 06-27-2010, 02:40 PM   #15
Admiral

 
seapuppy's Avatar
 
Join Date: Nov 2005
Location: Everett Wa
Posts: 4,681
Default

bout the only things you have are the coil...ignition module...ignition switch..a breaker...and a key.........so..if your not getting spark at certain times...one of those items may be intermitten...now one other thing to check..you should see a huge connector on top of the engine...pull that apart and clean the contacts...re-grease it with dielectric grease and re-connect.....

keep us informed...and thanks for posting back on this one..

SP
__________________
Don't compare your life to others. You have no idea what their journey is all about.
------------------------
SSN683 Association member
Par Excellence
------------------------------
2008 Bayliner 340 - "Wild Whim"
--------------------------------------
I live in my own little world....but it's okay-they know me here!!!

Avid practitioner of the martial art: KLIK-PAO.
Tap-Rack-Bang

Anyone that sez "Size doesn't matter" has never owned a boat!
seapuppy is offline   Reply With Quote
Old 06-28-2010, 01:28 PM   #16
Admiral

 
ss3964spd's Avatar
 
Join Date: Jul 2009
Location: Fairfax Va
Posts: 1,512
Send a message via Yahoo to ss3964spd
Default

Since no one can find the exact cause you are reduced to throwing parts at it. Can't quite tell if you actually replaced the ignition control module and coil or not. If not, do so. I've seen the ignition modules run just fine when cool, but act up when hot.

Also, if you've not done so, get a copy of the wiring schematic, so you can trace the entire ignition circuit. Definately do what Dodge mentioned above - start the engine, get it warmed, and open the engine cover - at night, the darker the better.

Finally, check your ground connections, especially the one that is probably bolted to the rear of the block.

Dan
ss3964spd is offline   Reply With Quote
Old 06-28-2010, 11:07 PM   #17
Lt. JG
 
Join Date: Apr 2009
Location: Loch Lomond Scotland
Posts: 31
Default

Quote:
Originally Posted by ss3964spd View Post
Since no one can find the exact cause you are reduced to throwing parts at it. Can't quite tell if you actually replaced the ignition control module and coil or not. If not, do so. I've seen the ignition modules run just fine when cool, but act up when hot.

Also, if you've not done so, get a copy of the wiring schematic, so you can trace the entire ignition circuit. Definately do what Dodge mentioned above - start the engine, get it warmed, and open the engine cover - at night, the darker the better.

Finally, check your ground connections, especially the one that is probably bolted to the rear of the block.

Dan
Hi Dan

Yes i did replace ignition coil & module

Any idea where to get a copy of the wiring schematic from as i want to check every connection here

Will go down at night and have a look

Cheers
gentlemanglobetrotter is offline   Reply With Quote
Old 07-03-2010, 10:51 PM   #18
Ensign
 
Join Date: Mar 2008
Location: mexico
Posts: 4
Default

So here it goes..I had the same problem with one of my 350 mag mpi motors.I was at the point of ripping off the fuel injection
and going with carbs.I had the advantage of swapping parts from the good running engine.I finally swaped ECMs and found out that the ECM was acting up when it warmed up. New ones cost to much so I installed a bilge exhaust fan and ducked the air over the ecm.Problem solved.If I forget to turn on the fan she will act up.I know I will need to replace the ecm soon.But, untill then this works.I hope this helps.
captainron is offline   Reply With Quote
Old 07-05-2010, 08:13 PM   #19
Lt. JG
 
Join Date: Apr 2009
Location: Loch Lomond Scotland
Posts: 31
Default

Quote:
Originally Posted by captainron View Post
So here it goes..I had the same problem with one of my 350 mag mpi motors.I was at the point of ripping off the fuel injection
and going with carbs.I had the advantage of swapping parts from the good running engine.I finally swaped ECMs and found out that the ECM was acting up when it warmed up. New ones cost to much so I installed a bilge exhaust fan and ducked the air over the ecm.Problem solved.If I forget to turn on the fan she will act up.I know I will need to replace the ecm soon.But, untill then this works.I hope this helps.
Interesting Captainron as that is next on my list, i am lucky that my Merc dealer has a spare Mag 350 with a cracked block (insurance replaced) so i now have access to all the bits i need to try, i have the ecm, the HT lead for the coil also another switch for being in gear or somethingto try

As the spark is intermittent and as far as i'm aware the ecm takes the inputs from sensors ie crank sensor etc and then must output to at least the coil or ignition module to tell it when to spark then this is my next diagnosis that the ecm is breaking down and i so so so hope your right mate although if it proves to be i may try your fan idea as i see they are approx $1100 to $1400 for new, try $2500 in rip of Britain
gentlemanglobetrotter is offline   Reply With Quote
Old 07-08-2010, 01:28 PM   #20
Lt. JG
 
Join Date: Apr 2009
Location: Loch Lomond Scotland
Posts: 31
Default

Changed ECM along with start neutral safety switch & HT lead from coil, problem still exists so hoping to get crankshaft sensor and power relay to change over

I think after that its then down to a dodgy connection
__________________

gentlemanglobetrotter is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
alpha 1 problems ? keith66 Engines 6 11-29-2009 04:06 PM

Powered by vBadvanced CMPS v3.2.3

All times are GMT. The time now is 12:16 AM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2020, vBulletin Solutions, Inc.