2002 Mercrusier 5.0 MPI alpha drive service bulletin & jumper wire going to the ECM

[Corbinsc35]

2002 Mercrusier 5.0 MPI alpha drive service bulletin & jumper wire going to the ECM

Hello,

I have a I/o 2002 Mercruiser 5.0 MPI alpha drive in my Pontoon.

Does anyone know where to find the service bulletin or manual for the motor? Do you have a link?

&

Also i'm having problems with my motor randomly shutting off once I put it in gear. It idels fine and sounds great, but it dies abruptly and without warning once its in gear. It will die at any RPMS. It shuts off out of no where without any beeping or anything. Iv started a process of elimination trying to fix the problem, but no luck.

Looking at an article I found on here, it looks like a guy named Dubie had the exact same problem as me. Except he didn't really explain what he did to fix it. He had no pictures or videos explaining how he did this. Here is the forum link.

https://forums.iboats.com/forum/eng...l-mpi-2002-merc-engine-cuts-out-for-no-reason

He apparently installed a jumper wire is on the shift interrupter switch to the ECM. Im not sure what hes talking about or what Jumper wire he's referring too. Does anyone know exactly what he's talking about or can anyone help me?

Iv already started a process of elimination trying to fix this motor for the past two weeks. Iv changed a lot of parts and even had a mechanic look at it and brought it to a boat shop. Everyone seems to be stumped by it. Here is my original forum I posted about my problem.

https://forums.iboats.com/forum/eng...shuts-off-while-driving-in-my-2002-jc-tritoon


I really think it's the Shift interrupter from what Dubie experienced with his. I need help!

Thanks!

 

[Fun Times]

Corbinsc35 , I'll be assuming you have an Alpha Stern Drive for me posting this info beforehand but here is a link to your question regarding what Dubie did to his alpha drive, https://manualzz.com/doc/23430314/service-bulletin---marinemechanic.com

Dubie jumped the wires between A and C of the engine side wiring harness going to the shift interrupt switch...He also mentioned he left the jumper wire in place instead of buying a new ECM or having it repaired or trying one other recommendation once mentioned by Mercruiser service tech support that I can share should you find the need to try it after the test.

Please know while leaving the jumper wire in place may have seemed to have worked for him at the time but it is very, very dangerous to leave the wire in place and not use the shift switch as the shifting becomes very difficult to use while going in and OUT of gear especially around the docks as you use it the most, plus loading the boat on the trailer and around other people all doing the same...Add some wind gusts and high current flows, at some point he may get into a bad situation...Then add in the extra force of binding on the shift cables, shift linkage to the drive, inner damage to the stern drive gearing systems, that could add up to the cost of a new ECM or more.

Here's the highlight of that bulletin
Warning: When performing this test, the boat must be in the water. The drive unit will be difficult to get out of gear so do the test in an area that will allow the engine to be shut off in gear after the test so that the shift interrupt switch can be reconnected to the engine wiring harness again before proceeding back to the dock.

Step # 3. MCM V6 and V8 MPI Alpha engines only: If you have an Alpha engine with an engine miss-fire or if the engine shuts off above 1200 rpm, the problem may be caused by the shift interrupt switch. To determine if the interrupt switch is the cause, disconnect the switch from the engine wiring harness. Use a small jumper wire to go between the A and C terminals in the engine harness connector.

 

[Searay205]

Why not just disconnect the switch on the manifold. Fine for a test but sucks to live with that switch bypass. What you will find is you will pull so hard to get out of forward it will go straight to reverse. you will learn to live in gear because pulling out of forward always takes to reverse UNLESS you are idling for 45 plus seconds or going as slow as possible then you can pull it into neutral. Real fun when coast gaurd does a safety check and your circling like a shark...

 

[Corbinsc35]

Corbinsc35 , I'll be assuming you have an Alpha Stern Drive for me posting this info beforehand but here is a link to your question regarding what Dubie did to his alpha drive, https://manualzz.com/doc/23430314/service-bulletin---marinemechanic.com

Dubie jumped the wires between A and C of the engine side wiring harness going to the shift interrupt switch...He also mentioned he left the jumper wire in place instead of buying a new ECM or having it repaired or trying one other recommendation once mentioned by Mercruiser service tech support that I can share should you find the need to try it after the test.

Please know while leaving the jumper wire in place may have seemed to have worked for him at the time but it is very, very dangerous to leave the wire in place and not use the shift switch as the shifting becomes very difficult to use while going in and OUT of gear especially around the docks as you use it the most, plus loading the boat on the trailer and around other people all doing the same...Add some wind gusts and high current flows, at some point he may get into a bad situation...Then add in the extra force of binding on the shift cables, shift linkage to the drive, inner damage to the stern drive gearing systems, that could add up to the cost of a new ECM or more.

Here's the highlight of that bulletin
Warning: When performing this test, the boat must be in the water. The drive unit will be difficult to get out of gear so do the test in an area that will allow the engine to be shut off in gear after the test so that the shift interrupt switch can be reconnected to the engine wiring harness again before proceeding back to the dock.

Step # 3. MCM V6 and V8 MPI Alpha engines only: If you have an Alpha engine with an engine miss-fire or if the engine shuts off above 1200 rpm, the problem may be caused by the shift interrupt switch. To determine if the interrupt switch is the cause, disconnect the switch from the engine wiring harness. Use a small jumper wire to go between the A and C terminals in the engine harness connector.

Can I just buy a new interrupter switch? Will that fix the problem

 

[Corbinsc35]

Yes, its an alpha stern drive

 

[Corbinsc35]

Corbinsc35 , I'll be assuming you have an Alpha Stern Drive for me posting this info beforehand but here is a link to your question regarding what Dubie did to his alpha drive, https://manualzz.com/doc/23430314/service-bulletin---marinemechanic.com

Dubie jumped the wires between A and C of the engine side wiring harness going to the shift interrupt switch...He also mentioned he left the jumper wire in place instead of buying a new ECM or having it repaired or trying one other recommendation once mentioned by Mercruiser service tech support that I can share should you find the need to try it after the test.

Please know while leaving the jumper wire in place may have seemed to have worked for him at the time but it is very, very dangerous to leave the wire in place and not use the shift switch as the shifting becomes very difficult to use while going in and OUT of gear especially around the docks as you use it the most, plus loading the boat on the trailer and around other people all doing the same...Add some wind gusts and high current flows, at some point he may get into a bad situation...Then add in the extra force of binding on the shift cables, shift linkage to the drive, inner damage to the stern drive gearing systems, that could add up to the cost of a new ECM or more.

Here's the highlight of that bulletin
Warning: When performing this test, the boat must be in the water. The drive unit will be difficult to get out of gear so do the test in an area that will allow the engine to be shut off in gear after the test so that the shift interrupt switch can be reconnected to the engine wiring harness again before proceeding back to the dock.

Step # 3. MCM V6 and V8 MPI Alpha engines only: If you have an Alpha engine with an engine miss-fire or if the engine shuts off above 1200 rpm, the problem may be caused by the shift interrupt switch. To determine if the interrupt switch is the cause, disconnect the switch from the engine wiring harness. Use a small jumper wire to go between the A and C terminals in the engine harness connector.

Thank you for responding Fun Times, I appreciate it. Especially with useful information.

Do you know if I can just replace the sensor? Will putting a new interrupter switch on there fix the problem?

 

[russvanatter]

I had a similar issue on older MCM. Turned out to be a cracked negative battery terminal. Tried everything up to that point and when removing battery, terminal feel apart. New battery cable and problem solved.