TOPIC: Timing Question (yet another)

I need to validate my thinking on how the system works and "max spark advance"

As the main throttle handle at the controls is pushed forward the distributor rotates, advancing the timing. The engine picks up revs not because the carbs are opening up with more air/gas, but rather because the timing is advancing (by way of the distributor rotating). The distributor only rotates so far before being stopped (at what should be the specified timing setting). Now, as the main throttle handle continues forward on it's way to max throttle, the "throttle pickup" linkage engages and now the butterfly valves on the carbs start to open. So engine revs pick up based on more gas/air, but the timing stays constant at this point

According to the manual, the "spark advance" on a '63 1000 is .222 BTDC.
Am I correct in my understanding that this means that when the distributor is at it's max rotation, it should be firing a spark at .222 BTDC. So if I have made a mark on the flywheel at .222 BTDC with a corresponding one on the block, when using a timing light, I want to set the timing advance stop such that it stops the rotation of the distributor at the point where the .222 marks line up as seen under the flash of the timing light.

marks should be there as I remember. ground the ignition and you just need to run the starter to do it.

Thanks Dave....

How about my description on how it all works? Accurate?

yes it is . that is why they are called an economizer.

Dave if you ground the ignition how is the timing light going to work?
So if I get this straight you place the timing light on no. 1 cylinder and using thetiming marks on the fly wheel. Mine has 2 of them one is at the 235 degree pt. That is the one I would use on a 1960 Mercury 400. Set the throttle to the full distributer advance point and adjust the max advance or throttle stop bracket so that it flashes on the .235 in my case or .222 in Peters case.
We should be able to do this with just the starter motor.

ground 5 plug wires and hook the timing light to #1 wire. mark should be 222 if it is the correct flywheel.

Hi Peter, Dave, & Tom,
Peter, I somewhat disagree with your description. Dave typically likes to give very short answers, but he definitely knows what he is talking about. However, yes when the distributor is first rotating, only timing is advancing. Then the Primary Pick-Up point (setting) is reached where the carburetor(s) start to open. As the distributor continues to rotate (and advance timing), both the carburetor(s) and timing advance until the Maximum Spark Advance point (setting) is reached. It is true that the carburetor(s) have not opened very much at this point, and that continued rotation until the Throttle Stop point (setting) is reached, is all carburetor(s) opening only. That said, on several Mercurys, the Idle Stop point (setting) will often be effectively set at the Primary Pick-Up point, or very close (below it, never above) to it. In such cases, the result is that both timing and carburetor(s) opening will occur until the Maximum Spark point, from idle up.
Although this has not been part of the discussion, I will also mention propellers here, as the incorrect pitch propeller is also a factor. True, it does not alter the discussion above, but an uncountable number of times, I have heard that "this is the propeller my boat can with", or "I do not plan on running wide-open", so the engine rpms through-out the ignition advance curve are now in error with the incorrect propeller pitch. Certainly, this is more serious with too higher pitch, but can be a problem with quite a lower pitch. For those reading who do not know, unlike a car or many other motors, there is no feature to retard timing when unexpected high load is placed on the engine (like a car driving on level ground, which starts up a hill), as too higher propeller pitch does, so the timing is too far advanced for the engine rpms it is achieving over much of the engine operating range. Serious engine damage is awaiting (the cooling system becomes weaker due to an older water pump impeller; more persons or gear are added to the boat than usual; poorer gasoline is unlucky purchased; etc.).

Regards,
Joe
www.fergusonpoolemarine.com
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Thanks Joe! Your post is perfectly timed. I was thinking about it and thought; "wait, if the throttle pick up is starts at .015 BTDC (per the manual), and max advance is .222 BTDC, then for a period of rotation of the distro, the carbs are opening as well and the spark advancing.

I think.