1984 115 HP 6 in line Merc Timing Conflicting Information

[GHBART]

The timing of the the Primary Pick-Up is the subject.
All sources set the IDLE STOP to align the embosed arrow to the embosed line
With this complete, I have three sources of what the ignition timing should be at this point.
I have a SELOC manual that indicates 4-6 degrees BTDC.
I have info from a Forum (I can't relocate that forum, it has pictures marked up with arrows and text on how to do tiiming) that says the following as I quote.
Identify the 4 and 6 degree marks AFTER TDC - NOT BEFORE TDC so counter-clockwise to the 4-6 degreemarks from TDC.
Another source indicates that the engine idles with timing ATDC and as the cam touches the carb roller it would be TDC and then advances BTDC reaching a max of 20 degrees at cranking speed.
This engine starts every time and runs wide open and at all speeds below with one problem.
If I set the idle in neutral, it idles well.
If I set the idle with shift in forward, it idles well
The problem, I can't shift from neutral to forward or forward to netural and not have the engine stall.
It will restart with no problem.

 

[Bob_VT]

Re: 1984 115 HP Timing Conflicting Information

Re: 1984 115 HP Timing Conflicting Information

http://forums.iboats.com/showthread.php?t=168855 This is the information from Clams Canino and he is my inline guru

When I first did it .... I ended up doing the procedure 3 times before I was comfortable it was right.

 

[arsenalpsu]

Re: 1984 115 HP 6 in line Merc Timing Conflicting Information

You are mixing two timing events that are different. PRIMARY PICK timing for that engine is 5-7 ATDC, IDLE timing "is what is" to get your idle where it needs to be.

Primary pickup is when the throttle is advanced to the point where the carbs start to open, when this happens you need to be at the specified timing. Once you set your primary pickup you have to adjust the linkage to get your idle under 1000RPM, too low and your tower will stall when put in gear, too high and you'll beat up your LU (1000 is worst case- 800 is better). When adjusting the idle speed you're really only messing with the timing, the carbs should be closed the whole time.

The "link and sink" from clams on here is pretty general, the CDI 115hp ignition is 5-7ATDC, as per my Mercury factory manual. This varies per HP and if you have a distributor or CDI.

 

[GHBART]

Re: 1984 115 HP 6 in line Merc Timing Conflicting Information

Thanks a bunch. I'm now getting the info I need.
More clarification please.
You said "Primary pickup is when the throttle is advanced to the point where the carbs start to open, when this happens you need to be at the specified timing"
If I understand correctly from info I have I should do the following to be at that point.
1 Align the Arrow on the crankcase with the mark on the throttle cam by adjusting the Idle Speed adjusting screw.
2. Adjust the Carburetor lever so that it barely touches the cam with the carbs fully closed.
If I understand you correctly, with these adjustments made, I should now adjust the primary pickup adjusting screw to fire cylinder #1 at 4-6 degrees ATDC (AFTER Top Dead Center)

 

[arsenalpsu]

Re: 1984 115 HP 6 in line Merc Timing Conflicting Information

That's correct. Once you do this and start her up you may notice that the idle is too fast, when you then adjust the idle stop (and cable linkage) to back down the idle this will retard the timing only so you may be closer to 8 or higher ATDC for idle timing. Each engine differs on idle timing depening on many factors, BUT onces the system hits and starts to open the carbs the timing is the same per model/year/hp...etc.