Spark Advance 55 HP 1968

[Car Guy Buys Boat]

I have a 55HP 1968 johnson motor 3 cyl 2 stroke. It has the point ignition with electronic amplifier.

I am ditching the distributor cap, electronic amplifier, coil, and converting to coil on plug ignition with a crank trigger. I need to program the spark advance curve.

I have a manual and cannot find the following:

Ignition advance curve profile,
what is the total advance at full throttle,
and for sake of argument, what is the timing at idle to be set at.

A table would be very helpful, for example:

600 rpm = 6 degrees ATDC
900 rpm = 4 degrees ATDC
1200 rpm = 2 degrees ATDC
1500 rpm = 0 degrees TDC
1800 rpm = 2 degrees BTDC
.
.
.
3500 rpm = 25 degrees BTDC
4000 rpm = 28 degrees BTDC
4500 rpm = 28 degrees BTDC
5000 rpm = 28 degress BTDC

Thanks to anyone who might be able to help with this missing info.

 

[F_R]

Re: Spark Advance 55 HP 1968

Lots of luck on that one. I doubt such information was ever published.

You should be able to figure out the full advance by the timing mark on the flywheel.

 

[Car Guy Buys Boat]

Re: Spark Advance 55 HP 1968

No doubt, it will be easy to set the initial timing, by merely confirm TDC on cylinder 1 and it had better line up with the timing marks on the flywheel. Now it is just a matter of finding initial and full advance timing parameters. I guess if it ran reliably, and I could take it on the water and run it WOT and put a timing light on it . . . .

Someone out there must know.

Lots of luck on that one. I doubt such information was ever published.

You should be able to figure out the full advance by the timing mark on the flywheel.

 

[Car Guy Buys Boat]

Re: Spark Advance 55 HP 1968

No doubt, it will be easy to set the initial timing, by merely confirm TDC on cylinder 1 and it had better line up with the timing marks on the flywheel. Now it is just a matter of finding initial and full advance timing parameters. I guess if it ran reliably, and I could take it on the water and run it WOT and put a timing light on it . . . .

Someone out there must know.

Lots of luck on that one. I doubt such information was ever published.

You should be able to figure out the full advance by the timing mark on the flywheel.