Timing Advance on 2000 3.0 with EST

[RaceCarRich]

New guy here says hello. Just got my first boat and am learning all I can. Was giving my used boat a once over and tune-up before taking to water. Noticed the following:

Timing in Base Mode: 2 ATDC like posted on flame arrestor = COOL
At Idle (out of Base Mode): 11-12 BTDC = COOL
Full Advance (out of Base Mode): 20 BTDC @ as high as 2800. = NOT COOL???

Everything I have read says it should be 27 BTDC all in. Also, most of what I have read would indicate it is common for base spec to be 1 ATDC unlike what the stock (I know the original owner & he didn't change it) flame arrestor specs of mine.

Do you think the issue is in the module? Is this a common failure mode? Does my engine have a slightly difference advance curve from the more common ones I've read about and, if so, what is the full advance spec? How concerned should I be?

Thanks in advance

 

[Bondo]

Ayuh,.... Welcome Aboard,..... I ain't got yer answer, but I'll bump this back to the top,....

 

[Fun Times]

I've seen two different reports as far as timing specs with these ignition modules. One says 23 and the other says 27.,,,,Should you decide to check the advance curve while under mid acceleration (load), there's a chance the advance numbers will go up some. And come to think of it, I've seen these same modules lower themselves to the 19 degree range at WOT so you may not have an issue per say. If the engine performance is lacking from possible under timed, then it's time to try a new module.

The cost efficient way to test for a problem is to buy a new module. But while the latest Mercruiser part number is 811637001 at a cost of around $190.00 the same part from AC-Delco part number D1965A can be found for around the $40.00 $66.00 range online or probably an auto parts store too. Here's two examples, http://www.ebay.com/sch/i.html?_from...1965A&_sacat=0
http://www.rockauto.com/catalog/rafr...ktemplate=true

Forum member fishrdan did some past digging and testing on this himself,
http://forums.iboats.com/forum/engin...advance-enough

Also I believe the 27 degrees total advance that we are reading in the service manuals is possibly a misprint since the chart and specs show/say 23 degrees total.
MCM 3.0L, 3.0LX (S/N 0D504542 and Above) With EST
Module Part Number: 811637 Module Advance: See Notice Initial Timing: 1? BTDC Total Advance: 23? @ 2800 RPM: NOTICE
Advance curve includes initial timing. DO NOT add initial timing degrees to total advance degrees.

 

[RaceCarRich]

Thanks a bunch. I found another manual online that shows the same exact graph as page 6 of the bulletin linked on fishdans post (showing full advance 21min. - 24max) but with accompanying language printed that said full advance was 27. I think its a typo and I should just run it.

Also find it strange that all info on web always refers to base as 1ATDC and my flame arrestor states 2ATDC. That 1 degree could be the difference between 21 and 20 all in when using the same module.

 

[Fun Times]

Yes the timing has bounced around a little bit between 1 & 2 degrees with this style ignition system. The older systems were more in the 8 degree range.

They had a few problems with keeping up along he way,
MCM 3.0L Flame Arrestor Decal
MCM 3.0L Flame Arrestor Decal
3.0L Engines with Blown Head Gasket
Ignition Advance Curves and Point Setting

 

[fishrdan]

2 questions, what was the engine RPM at idle while checking the timing (SB 650-700RPM) and how did you check the full advance at 2800RPM, with an advance timing light?

If your spark arrestor says 2* ATDC, that's why your full timing at 2800RPM is at 20-21*. Different years of the 3.0L had different initial timing (1* BTDC, 1* ATDC, 2* ATDC, due to how the engine was built, compression, head, etc. etc... The timing on your engine was retarded a bit, and this is not necessarily bad as some engines that experienced blown head gaskets had the timing retarded. I wouldn't worry about it and run with what you have as it sounds like it's within spec.

My engine is a bit different as I'm running an EST ignition on an old 1973 140HP (3.0L) that's built different: lower compression, different pistons and head, and those differences would allow for more timing. Plus the gas was better back then, non-ethanol. Even though my engine could most likely handle more total timing (no way to do it with the EST unless I played with different modules) it still runs just fine with the EST giving around 24* total timing.

So.... If your timing is correct and you're getting 20* plus timing... I wouldn't worry about it.