Help with reserrecting a sunk 350 Mag

[Etzler]

Purchase a sunk 2008 ski boat with a 350 MPI motor. The boat was submerged for five days at a depth of fifty feet in fresh water. I have been able to revive most of the accessories up to the engine. The engine will turn over, but the main power relay isn't working. It has power on two of the four connections with the key on or off, it doesn't matter. Where to begin?

 

[Fun Times]

Purchase a sunk 2008 ski boat with a 350 MPI motor. The engine will turn over, but the main power relay isn't working. It has power on two of the four connections with the key on or off, it doesn't matter. Where to begin?

Being an 2008, what are the colors of all the wires going to the main power relay? I ask due to the small possibility of the wires changing colors slightly between an older service manual that's available online for look up to changes made by Mercruiser starting in 2007 to where MPI wiring diagrams are no longer available in regular service manuals but are now in a special paper format mostly for the dealerships use but should be orderable if requested for your engine model should the need arise. That mentioned, the main relay may have stayed the same color, etc. etc. Just wanted the info to be clear before going to deep because the newer the engines get, the added difficulty of being able to help precisely as we try our best to do.

Knowing the engine serial number might help some of us too.

Have you tried either swapping the relays around or tried new relays to see if they help at all or at least change what seems to be happening?
The manual we'll be referencing off of seems to indicate there are 3 fuses that head to the main power relay...Have you thoroughly checked and cleaned all the fuses found near the ECM? Also check the 50 amp circuit breaker for good 12v power at both ends.

Do you have spark coming out of the coil tower to the distributor cap?
Does the tachometer gauge move up to around 300 RPM while cranking the engine over.

 

[Etzler]

Being an 2008, what are the colors of all the wires going to the main power relay? I ask due to the small possibility of the wires changing colors slightly between an older service manual that's available online for look up to changes made by Mercruiser starting in 2007 to where MPI wiring diagrams are no longer available in regular service manuals but are now in a special paper format mostly for the dealerships use but should be orderable if requested for your engine model should the need arise. That mentioned, the main relay may have stayed the same color, etc. etc. Just wanted the info to be clear before going to deep because the newer the engines get, the added difficulty of being able to help precisely as we try our best to do.

Knowing the engine serial number might help some of us too.

Have you tried either swapping the relays around or tried new relays to see if they help at all or at least change what seems to be happening?
The manual we'll be referencing off of seems to indicate there are 3 fuses that head to the main power relay...Have you thoroughly checked and cleaned all the fuses found near the ECM? Also check the 50 amp circuit breaker for good 12v power at both ends.

Do you have spark coming out of the coil tower to the distributor cap?
Does the tachometer gauge move up to around 300 RPM while cranking the engine over.

First thanks for the reply. Haven't tried to get spark until I get some other electrical worked out,Fuel pumps and such.
The serial number for this OW698323'. You mentioned fuses. There is a cluster of four in a weather tight connection near the distributer they are all good. The wire color for the main power relay. Terminal 86 (red/purple) and 30 ( red/ purple) both have power with the switch on or off. Terminal 85 ( purple/teal) and 87 (Red/blue) never have power. All relays have been replaced.

 

[Fun Times]

The colors seem close in color to the available manual online so manual 36 will help guide you through this process.

Terminals 30 and 86 should always have power so you're good there. Terminal 87 should become powered up only during engine crank or running which is activated when the ECM wire "terminal 85" sends the activation signal either for 2 seconds at key up or when the ECM sees an RPM signal for both engine cranking and or running from ECM pin out number A-22 which is said to be purple/dark green. You may not see power from 85.

You also should have what is known as clean power which is a wire harness from the battery to the engine and there should be a fuse there at/near the battery that needs checked and be sure the connections are clean and tight. See item numbers 24, 25 & 26, http://www.crowleymarine.com/mercury...s/12844_30.cfm

Engine notes:
MIE 350 MAG SKI, 71C 1.0, VDR READY, Model # 33500366S
http://www.iboats.com/350-MAG-MPI-SK...iew_id.1692038

This past topic sort of covers something's that might be of a helpful guide too.
http://forums.iboats.com/forum/engin...i-blowing-fuse

 

[Etzler]

Replaced the ECM, that brought may of the systems back to life. Now cranking the motor I only get a very occasional fire. Replaced plugs, wires, cap, rotor, coil and crank sensor. What other items would cause spark issues? Fuel pressure was around 40 psi.

 

[Oshkosh1]

Replaced the ECM, that brought may of the systems back to life. Now cranking the motor I only get a very occasional fire. Replaced plugs, wires, cap, rotor, coil and crank sensor. What other items would cause spark issues? Fuel pressure was around 40 psi.

"Occasional"...So you ARE getting fire...just sporadic? In that case I'd start looking for a contact issue somewhere rather than something systemic. Still a bad ground or flaky junction somewhere. Don't be stingy on the brake cleaner...I'd be hosing that thing down with a case of it to displace every bit of moisture I could. After that, lots of grease on the wiring.

 

[Etzler]

"Occasional"...So you ARE getting fire...just sporadic? In that case I'd start looking for a contact issue somewhere rather than something systemic. Still a bad ground or flaky junction somewhere. Don't be stingy on the brake cleaner...I'd be hosing that thing down with a case of it to displace every bit of moisture I could. After that, lots of grease on the wiring.

I have cleaned all connections with contact cleaner. Hoping to find another component that may be affecting the spark.

 

[Fun Times]

Cranking the motor I only get a very occasional fire.

Is the spark sporadic coming directly out of the coil or just the spark plug end wires? You need to ensure there is a strong consistent spark coming out of the coil before moving down the rest of the ignition system.

Own a timing light? If so, Put the timing light inductive pickup clamp on the coil wire and watch for a consistent spark flash.

 

[Oshkosh1]

You can also use the timing light on any/all of the plug wires to see if it's limited to a specific cylinder. If the light flashes, there's charge in the wire, if not...it's dead.

 

[Etzler]

Is the spark sporadic coming directly out of the coil or just the spark plug end wires? You need to ensure there is a strong consistent spark coming out of the coil before moving down the rest of the ignition system.

Own a timing light? If so, Put the timing light inductive pickup clamp on the coil wire and watch for a consistent spark flash.

Great idea. I will give it a check..

 

[Etzler]

You can also use the timing light on any/all of the plug wires to see if it's limited to a specific cylinder. If the light flashes, there's charge in the wire, if not...it's dead.

I will check. Thanks

 

[Etzler]

Well,I checked the coil wire with at timing light. Sparking like crazy. Checked other wires and everything seems fine, just seems the timing is off. I call the place where I got the replacement ECM and the only advice they offered was to send the ECM back. Got lucky with them accepting a return, I would hate to buy another one and have the same issue. How hard would it be to convert motor back to carb? Biggest concern would be getting the gauges to work.

 

[Scott06]

Would check the following Before sending back control unit

one did you set the timing? Check number one plug wire with timing light like you're setting the based timing at eight or 10 degrees before top dead center- have some one run starter and check with light. If that is OK spray starting fluid down intake and run. If your ignition is good it should show some resemblance of running on the starting fluid and you need to focus on the fuel.

2. Fuel pressure and are injectors opening when triggered. Not 100% sure how to do this but would find out if 12 v is supplied to each injector or if the computer opens and closes the ground to each injector.

3. Crankshaft position sensor on lower left of timing cover, again don't know how to but I'm sure it's in the manual

4. Fuel pump most likely is powered via the starter during starting and goes through oil pressure switch once running if no fuel pressure check this- is the fuel pressure consistent or are you loosing it

 

[dingdongs]

Disconnect cable that feeds to the rev counter as this may be giving a no start condition if its faulty.

 

[Etzler]

Disconnect cable that feeds to the rev counter as this may be giving a no start condition if its faulty.

Where is the rev counter?

 

[Etzler]

No Title

Pulled all the spark plugs and checked to make sure the firing order is correct Reset the distributor to guarantee it was set up correct. After a very liberal dose of starting fluid it fired off, but still wouldn't run. Led me to believe a fuel issue. Tested fuel pressure. 36 psi. Checked all the injector leads with a noid light. Finally I pulled the fuel rails with the injectors attached and turned the key to the on position for the initial injectors fire. Only two injectors were working. This is what I found. The old ECU melted the injectors.

 

[Fun Times]

I checked the coil wire with at timing light. Sparking like crazy. Checked other wires and everything seems fine, just seems the timing is off.

Since your looking for another component that could affect spark, than you may or may not (50/50 chance) have a CAM Shaft Sensor connected/plugged in mounted under the distributor cap. Check to see if a wiring harness connector is plugged in or not and be sure the harness isn't laying off to the side someplace due to some engine models used the CAM sensor while some did not for your engine year time frame. The parts diagram seems to be saying yours is not used but you don't really know until you have a good look around. Item number 6, http://www.mercruiserparts.com/bam/s...31404/12844/40

I call the place where I got the replacement ECM and the only advice they offered was to send the ECM back. Got lucky with them accepting a return, I would hate to buy another one and have the same issue. How hard would it be to convert motor back to carb? Biggest concern would be getting the gauges to work.

If I read correctly above, you bought a new ECM, and things seemed to be better as more items came alive. How come you wanted to return it if it seemed to help with something? Are you having it retested? Was the old one full of water?

The rev counter should be the tachometer (RPM) gauge. Should it be internally shorted out, it could keep the engine from starting. As part of an ignition test, one of the first things to try is disconnecting the Gray wire behind the gauge as that should be the easiest way to disconnect the Tachometer signal wire running between the gauge and ignition coil especially on your coil design.

You never answered post number 2 if the Tachometer gauge moves up to around 350 RPM when cranking over the engine?.. The more info from you might help us trigger a thought to try elsewhere.

Since you know the coil has spark, now use the timing light on all 8 plug wires to see if the flashes seem consistent as the engine rotates over via the ignition switch key.

While starting fluid is frowned upon here on iboats due to potential damage it may cause, Using just a little bit or better yet, using a little bit of fuel down the throttle body is sometimes a quick way to know if you need to concentrate on, the 12 and 5 volt power systems as you seemed to indicate possible issues with the relays and fuses at the beginning, Or a fuel injector problem whether it be power or fuel flow issues.

Edit: Somehow I missed post number 16 while texting out this post. Looks like 8 new injector are in order. Don't convert to carburation, you should almost be ready to go soon.

 

[scoflaw]

I'd take that Cool Fuel unit apart, checking the 2 pumps and the FPR , before installing the new injectors.. That system upstream of them needs to be spotless. That CF3 is also prone to the flaking paint issue which will plug things up downstream

 

[Scott06]

Check out five o Motorsport online. When I was loooking for injectors for my Seadoo they had both OEM and aftermarket at good prices