OMC 5.7 L with EST and without ESA

[ewerhin]

Hi guys

I've been reading through this forum, looking for some advice regarding a shifting problem I'm facing. My OMC 350 5.7 L 1990 does have an EST distributor, but the last owner did not installed the ESA CDI 123-7566.
Now I realized that there is an issue when going back to neutral from FWD and REV, it is very hard, and sometimes it does not go to Neutral at all.
So then I've got 2 questions:

a) Should I install the ESA? is it safe to work without the ESA in this configuration?

b) If it's better to install the ESA, is anywhere a wiring diagram or instructions to check how to connect all the cables? I've found this diagram:
https://www.offshoremarineparts.com/media/documents/CDI-123-7566.pdf

but I cannot understand how to connect the overstroke and cutoff switches, also not sure what "Shift Interrupt switch" is, not sure it's the same than cutoff switch.

Thank you very much guys!

 

[Scott Danforth]

welcome aboard

A - yes, No

B - it grounds the negative side of the coil

 

[ab59]

unless the PO cut the wiring harness there should already be plugs to accommodate the ESA. Just mount it and plug it in. Make sure you ground it , mine is grounded to the mounting bracket for the ESA . Are the switches gone off of the bracket or just sitting there unplugged ? You can buy new ones as they are available from many sources . Myself , I bought another fully dressed bracket with all the stuff still mounted on it. But that of course is used parts and you buy a pig in a Polk when buying used. Ebay have ESA mounting brackets if yours is gone. If you don't already have a Original repair manual get one , you will need it to maintain your boat anyway .

 

[ewerhin]

So you mean that both switches should be conected to the ESA, and the ESA just grounded? If so, how is the ESA grounded, because in the pics I've seen, the ESA just have one connector (for the switches, 4 wires) and that's all.

My switches are still there, but just unplugged.

I appreciate your replies and help, mates!

 

[alldodge]

Your file in your post above has an error, unable to see

The EST distributor uses 12V to interrupt the distributor on the right hand connector. The interrupt switch needs to be changed from applying a ground to have it apply 12V

This is a Merc 4cyl but works the same, and this shows how to set base timing more so timing can be adjusted.

 

[ewerhin]

Hey AllDodge

Thanks, your explanation is very useful to me, I appreciate.

I already ordered an ESA to complete the installation, but with your graphs it is much more clear. Still need to understand completely where does the ESA fits with all this configuration, but I'd figure it out I think.

 

[ewerhin]

I found this diagram which connects all together. Not very readable, but should be enough.