Set timming 80s tower power 90, merc.

[stevehendo34]

I saw how to do this on youtube statically.


Set primary pickup idle advance

1. Remove idle stop plate
2. Remove spark plug # 1 put it by ground
3. Set to timing mark ATDC 5 degrees
4. Twist distributor cap bank and forth
5. Listen or watch for spark on # 1
6. Look for black arm on distributor to just touch carb butterfly arm
7. If no loosen distributor screws on top and twist and adjust until # 5 true
8. re-install idle stop plate.

Can this just be done at idle with a timing light and marking 5 degrees on flywheel? What RPM should motor be at. Where do you hook a tachometer up to can yo use a one made to tune a car somehow?

Setting spark advance screw

1. Set to timing mark ATDC 20 degrees
2. Twist distributor cap bank and forth
3. Listen or watch for spark on # 1
4. When here or see spark set advance screw there

Can this just be done at idle with a timing light and marking 20 degrees on flywheel? What RPM should motor be at for full advance? Where do you hook a tachometer up to can yo use a one made to tune a car somehow?



The rest for my notes:

Set secondary pickup in back of distributor that's turns top portion of distributor?secondary pickup:

1. Rotate distributor back
2. When the base of the distributor stops set screw at that point.

Set throttle stop screw,(top one):
Pull on distributor arm aft
Set screw when its all the way aft + a bit more to let throttles open up completely.

 

[stevehendo34]

SOLVED:
figured out the link sync think and

 

[Chris1956]

Gee, That is not even close to what the factory recommends. Second, if you have a distributor, that motor is 1979 or older.

The correct link and synch is: Set #1 piston to .464" btdc, using dial indicator or steel ruler, micrometer etc. Adjust timing pointer to read .464 " BTDC, and lock it down.

Install #1 spark plug and wire. Remove spark plugs 2-6, and ground wires to block. Crank motor and adjust throttle until timing light reads 4-6* BTDC. Stop cranking and loosen set screws and adjust brass color on distributor until the plastic covered finger just touches the carb opening lever. Advance throttle to max, and crank motor. Adjust max spark advance set screw to read 12*BTDC. Make sure carbs are fully open by adjusting throttle stop to stop carbs from hitting their stops.

 

[stevehendo34]

Ok thanks found a manual that describe exactly what you are saying and yeas it is a 78-79
I have dial indicator and timing light
You made sound easier--less wordy than the manual--THANKS

"Adjust timing pointer to read .464 " BTDC, and lock it down."
That's a weird step unlike a car that you time from TDC to BTDC. not from .464 BTDC to 5 BTDC
​I think this it what you are telling me to do?
I wonder why they did that?

 

[Chris1956]

IMO, Mercury chose .464 inches BTDC to set the timing pointer, because that is a single point, and will force accurate timing. Remember, the flywheel moves 1/8 in or so, while piston is at TDC. If you set the timing pointer at TDC, are you setting it at the middle of TDC, the first part of TDC or the last part of TDC? It is hard to tell, and it will make a difference in the timing.

Once you have set the timing pointer, idle pickup timing is 4-6*BTDC, like a car engine.