Omc Ignition Wiring & Swap

[Sugo]

I have a cracked Omc 3.0 , I have picked up a Merc 3.0 long block with perfect compression and am swapping every thing over. My OMC is an 1988 with point style ignition and my replacement block has electronic ignition (1989) Should I swap out the distributor and use all my old stuff or can I use the electronic ign. Do I need any other components to make this work. My wire set was new, can I use the same leads with both style ignitions ? There seems to be more wires to the sides of the coil on the old sys. Does anyone have a link to an OMC wiring diagram that might help me with this.
I have swapped the front motor mount with out changing the adjustment and there is no rear adjustments, do I still need an alignment tool to re-install my cobra leg. At what stage would I need to use this tool (if necessary).
The replacement block has been sitting for a while (14 Months) Fogging oil was used when It was stored, Is there any special procedures I should use during an initial start up ?
Thanks for any help

 

[Fishermark]

Re: Omc Ignition Wiring & Swap

That's a lot of questions!

Someone more versed in OMC will come along shortly.... but I suggest bringing everything that came with the OMC engine over to the new engine. Including the distributor. Then get it running.

Then, if you want to mess around with going electronic you can do it after all the bugs have been worked out. I know that OMC has a different set up for shift interrupt, etc than Mercruiser does, so the K.I.S.S. principle applies.

 

[havasuboatman]

Re: Omc Ignition Wiring & Swap

Is the wiring harness for the new motor complete to the 10 pin connection?
If it is, you should be able to use the motor as is by pluging it into the boat harness.
Yes, alignment is absolutely necessary. You need it, alignment tool, when setting the final height of the front motor mounts. This is critical!!

 

[Don S]

Re: Omc Ignition Wiring & Swap

Is the wiring harness for the new motor complete to the 10 pin connection?
If it is, you should be able to use the motor as is by pluging it into the boat harness.

I doubt the exhaust will line up, and I know the shift interrupt and shift cable setup systems are different between Merc and OMC, and I know the ESA won't work with the DDIS ignition system, plus parts for the DDIS system are expensive and some are NLA. So to prevent a lot of re-engineering, I would suggest using the long block only, and sticking with the accessories from your old engine, including exhaust manifold and carb.

 

[Bondo]

Re: Omc Ignition Wiring & Swap

So to prevent a lot of re-engineering, I would suggest using the long block only, and sticking with the accessories from your old engine, including exhaust manifold and carb.

Ayuh,... The Long Block is the only thing Common between them,...
You need the OMC Package to make the motor run Properly...

 

[Sugo]

Re: Omc Ignition Wiring & Swap

Thanks for the help guys, I did swap everything including the manifold, so I will swap over the electrical as well.
I will be sure to winterize properly next time.

 

[Sugo]

Re: Omc Ignition Wiring & Swap

One more question, when I am installing the distributor in the replacement block how do I determine the correct position. Is it a different method for ESA vs DDIS ?

 

[Don S]

Re: Omc Ignition Wiring & Swap

Have you removed the DDIS distributor yet? If not, turn it up so the rotor is pointing to #1 spark plug wire and the timing mark on the pulley is lined up. Put your points distributor in the same way and make the #1 plug wire in the same place.

 

[Sugo]

Re: Omc Ignition Wiring & Swap

Good tip, That makes it straight forward.
Glad I asked.
Thanks

 

[havasuboatman]

Re: Omc Ignition Wiring & Swap

Let me apoligise for my earlier post, I somehow missed the fact that this was OMC to Merc.