Synching carbs and ignition on 1972 85 hp V4

[amuller]

I still had trouble understanding what to do, given that nothing was quite right. This is what I did,in order of doing. Errors?

Adjusted links to sync choke and throttle flaps.
Adjusted timing pointer with dial indicator, etc.
Adjusted max timing advance to 28 deg. BTDC (Static, not running).
Adjusted "idle" timing to 5 deg BTDC with "idle speed screw." (static).
Adjusted throttle cam so upper mark bisects pin by turning yoke on threaded link.
Adjusted pin/roller on throttle cam.
Adjusted full throttle stop so as to not "preload" throttle shafts.

[fleetwin]

OK, so the TDC indicator is OK…
But, you can not adjust timing on these engines statically….To adjust the WOT timing, the engine must be in gear and running at WOT, best to use a test wheel for this procedure…
Once again, there is some confusion about "idle timing". There is no spec for idle timing on this engine…The 5 deg BTDC spec is for the "pick up timing". The pick up timing is checked/adjusted while the engine is running with the upper mark on the cam bisecting the throttle roller, which is usually an off idle setting….
The idle speed is adjusted simply by turning the large idle stop screw in/out while the engine is running in gear (in the water with prop installed). Do not attempt to adjust idle speed while the engine is running on a flushette…Keep in mind that the gearcase oil pump puts a load on the engine while it is in neutral, even more of a load while it is in reverse….This isn’t much of an issue on the V4 models, but can cause frustration while trying to adjust the idle speed on the 3cylinder models.
Perhaps it is just the terminology that is confusing here and we are saying the same thing…. But, if you set idle timing to 5 deg BTDC, the engine will probably be idling way too high. As I recall, perhaps incorrectly, you are using a generic service manual, perhaps this is causing the confusion.
I think I have the correct OMC manual for this engine at home, but won’t be home for a few days….
And yes, that second/lower mark on the throttle cam is confusing, I don’t believe there are any sync adjustments using this mark.
Once I find and post the OEM sync instructions, I would be happy to discuss these procedures with you by phone…These procedures are not difficult, but tough to describe using the written word….
Finally, I am not sure I understand what you are describing when you say: "adjusted throttle cam so upper mark bisects pin by turning yoke on threaded link"……The throttle cam pick up is set by adjusting the throttle roller using the set screw on the roller. The pick up timing is set by turning the yoke on the threaded link rod. Again, my confusion might just be due to terminology….

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