1984 OMC 3.0 will not crank!

[mjs0815]

I have a 1984 SeaRay Seville with an OMC 3.0 Sterndrive. I've replaced the rotor button, spark plugs, ignition coil, and replaced the points with the Pertronix electronic conversion. The engine will turn over, and try to fire, but will not fully crank. After sitting overnight, it may crank up and run terribly! Then it will die and not crank back. I've replaced with a brand new Rochester 2B carb as well. I had it running the other night and cut it off, now it won't crank. I've tested with a spark tester and am getting fire. The timing appears to be correct, but I've adjusted the distributor slightly as well. Any help is much appreciated!!

 

[Scott Danforth]

welcome aboard

it wont crank, or it cranks and doesnt run?

stop throwing parts at it.

with the pertronix conversion, did you change the supply wire?
I personally never had luck with pertronix (having had multiple failures), and ended up back with points in my 3.0

by your comment on "timing appears to be correct". is it correct. did you set it with a timing light?

 

[mjs0815]

I haven't set the timing with a light yet. That will be this evening's project. It will turn over but sputters like it's trying to fire up. Then it won't do anything but turn over. I was going to put the points back in, but I apparently threw the old breaker plate away. There is a supply wire from the postive side of the coil to the pertronix. There is also a new positive wire directly from the ignition switch, or from the starter I'd have to check. The gray wire to the positive has not been changed.

 

[southkogs]

If you had them all off ... confirm the order of your spark plug wires. Not that I've ever put 'em on wrong before

 

[Scott Danforth]

Grey wire is tach and goes on negative side of coil. So wire it properly

New wire should be from ignition switch to coil.

No longer need wire from I terminal on starter

Never throw away your point plate. The pertronix instructions tell you to keep everything in the glove box in the event the pertronix module fails

You cant set timing without a timing light, however you sure can mess up your motor attempting to

Running to much advance on a 3.0 leads to holes burned in pistons