Springs on mechanical advance ..... different?

libellav15

Petty Officer 2nd Class
Joined
Jul 3, 2010
Messages
177
Hi guys

I am getting close to solving my issue with my timing problem.

Info - 1972 Mercruiser 120 - GM in line 4 with pre-alpha leg.

If you check my other threads you will see that i have had an issue with the timing advance.

With pot 1 at TDC (compression stroke) the timing mark on the balancer and the zero position on the block match up perfectly.

But then every time i try to set 6 degrees btdc at 600 rpm in forward gear the timing mark on the balancer was about 2 inches too far to the left - ie mega advanced. On trying to turn the dizzy to bring the balancer mark to the 6btdc mark she would stall before i got even close.

However.....

And any advice on this would be appreciated.....

I have pulled the distributor off, and checked the mechanical advance weights and springs for corrosion, damage, unfastened etc etc -

cleaned everything up and all nice and smooth action again but i noticed on re-assembly that both springs are really very puny ones.

even by spinning the cam by hand i can make both weights go to max out position.

I believe they are supposed to be one small and one chunky - is that right?

and where would i find the weight/tension of the springs i need - are they just standard for the engine/distributor type?

out of interest - how exactly does the weights moving outwards advance the timing?

cheers

adam
 
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