ECM location...

[harbormaster]

I have a 1995 18 classic with 350 mag.
How do you differenciate between the different models of ignition, Thunderbolt 4, 5 etc.?

Would this model have an ECM? If so where is it located??

Does anyone out there burn new ECM's

[Tidbart]

If yours is similar to mine, 1996 350 mag MPI. 1995 was the first MPI, but the EFI is very similar.
Just right of the plenum is a black box that the top opens. Inside is the ECM and interface. The ECM is a module about 3x6x1, roughly, with some multipin connectors to it.
If you need more info, I have the service manuals and just got the Merc videos on EFI.
Actually, give me all your engine info and I'll look it up tonight.
(350 Mag MPI Gen+ Bravo, SER OF06****)

Here is another option, I use this site all the time to find parts and prices, etc.

http://216.37.204.201/mercruiser_oem/mercruiser.asp?Type=11&SubType=111

See if this helps. If yours is an MPI, click on Electrical Box after you click on the right engine. Explore to find the parts.
An ECM costs over $1000.00 OUCH. Better not screw that one up.

Bob

[Tidbart]

Oh yah,
In answer to your other question, 'Does anyone out there burn new ECMs?'.

This guy does http://www.donzi.net/photos/cringerzf.jpg

Sorry, couldn't resist. :D

Bob

[harbormaster]

Thanks for the help Bob. My engine is carbed and not injected. I will post numbers shortly.

[Tidbart]

Scot,

Did some more homework for you. Here is what I can tell you about the two ignition systems

T-bolt IV - 2 variations, 1 had ignition module mounted on the exhaust bellows, the other had it mounted on the side of the distributor body.

T-bolt V - 1 type, it had an ignition control module and a knock control module mounted together, piggybacked on the side of the distributor body. The ICM has 8 wires, the KCM has 4.

All are the exact same distributor!!!

The only other way I can see of differentiating is by the Timing and RPM listed on the motor.

T-bolt IV - 650-750 RPM in forward gear with 8 deg BTDC timing.
T-bolt V - 650 RPM in neutral with 10 deg BTDC timing.

Note: T-bolt V has a special procedure for setting the timing. You can't use conventional methods.

Also, looks like the carbed versions, Tb IV has an Ignition Module (IM), TB V has an Ignition Control Module (ICM), and the fuel injected has the Electronic Control Module ECM). Big difference in price.

Hope this helps with all your questions. :D

Bob