Mercruiser 140 Distributor problem

DZ1956Lark

Recruit
Joined
May 10, 2014
Messages
2
I have a 1985 140 Mercruiser. I just put in nw rings, bearings. First time rebuilding. The crank and cam are lined up snd i just set my valve lash, all good. When i took the engine apart I marked the wires on the cap and notched the distributor. My question is where is the rotor supposed to be pointing to when i put it back in. #1 Cylinder is at TDC on compression stroke. Shouldn't the rotor be pointing to No. 1 cylinder. What is the proper way to start to get cylinder 1 to fire. Im so confused what points should be doing at TDC. THANKS FOR ANY HELP!
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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Jul 23, 2011
Messages
47,297
yes, with the motor at TDC on #1, the dizzy should be stabbed in so that the rotor is pointing to #1 lug on the cap. doesnt matter if you have points or electronic ignition.

are you sure your at TDC on number 1?

firing order is 1342


if you are certain you are on #1 cylinder, with the cap and wires removed, a black sharpie mark indicating where the #1 tower sits on the cap drawn on your dizzy, pull the dizzy out slightly until the cam gear dissengages, then rotate the rotor and shaft until it points to the #1 tower (accounting for the helix angle of the cam gear), and re-seat the dizzy. you will need to crank the motor to reseat the oil pump drive.

now install your cap and wires, set your gap and dwell, then set timing.
 

bajuski

Cadet
Joined
Oct 3, 2004
Messages
26
Spark occurs as soon as the points open so they should have opened at 8 degrees before TDC.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
47,297
Spark occurs as soon as the points open so they should have opened at 8 degrees before TDC.

thats a timing function (taken care of after stabbing the dizzy, setting dwell, etc.)
 
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