ESA identification help

Hello all,
I have done quite a bit of searching over the last few days and have come up with a ton of awesome information. What a cool site. I need a little help with finding a part number, as I don't have any tech manual yet. I have a boat with a 1981 OMC 140STHRCIF I/O. I am looking to upgrade to a new distributor and am having a tough time identifying the original part number for the ESA on this boat. Things are further complicated by the fact that the boat is stored quite a distance from my home, so I can't just pop over and take a look. I do have a list of 8 potential numbers, but have no idea which one should be used on this particular engine. Any help would be great.

Dave

Potential Johnson/Evinrude part numbers:
987740
987739
987738
986837
984730
982774
982755
982749

I looked and NONE of the parts diagrams I've seen doen't have any moduals listed???

1981 boats did not have ESA modules. The ESA system was introduced in 1982. Many earlier boats were retrofitted with a new lower unit and ESA system after the fact.
Regardless, just buy an aftermarket CDI unit for about 1/2 the price. Then, if you ever upgrade to electronic ignition, your CDI module will support it.

Hystat - I don't know which one to buy. There are a few to choose from and I just don't want to screw up and buy the wrong one.

Dave

123-9898P will work just fine. You may have to cut a couple wires to adapt to the style of connector on your boat, but it's straight forward and CDI will help too if you phone them.