Re: Replacing stator wires on a '79 90HP Mercury
You should be able to find a good used stator off eBay, these are quite common and any stator from a distributor-fired 99 C.I. motor should work.
The reason you don't want to use a jaw puller on the flywheel is you can break the 'flex plate' which is the thin, tempered steel part that joins the center hub and outer ring together. This type of flywheel typically dampens vibrations better than a solid flywheel but needs to be handled with care in order to prevent damage.
If you pull (2) bolts opposite each other and use an automotive harmonic balancer puller (along with Grade 8 or better 5/16"-NF bolts), you should be able to pull it right off. If you have an Autozone nearby, they rent free (with a refundable full-price-for-the-tool deposit) this type of puller.
The center hub is threaded for the factory-style screw-in puller which is also available aftermarket from a number of places (including here and on eBay to name a few). These work very well and usually "pop" the flywheel with little effort.
I'd like to suggest one more way, which, if you're careful, will also work: remove all the bolts holding the flex plate to the center hub and you can get the stator off without pulling the center hub.
Note that you need to make some very accurate match-marks on the flex plate and also on the hub, so you can bolt them back up in the exact position they were in prior to disassembly. Otherwise, you won't be able to check/adjust timing as the flywheel will no longer line up to Top Dead Center.
Before pulling everything apart you'll want to position the flywheel; run it around until the "TDC" mark is aligned with the timing pointer.
DO NOT move the flywheel or crankshaft after you've positioned it. As a safety, make additional match marks to relate a tooth on the flywheel to a stationary point on the block.
After than you can remove flywheel bolts then the flywheel assy (sans hub).
Once you've pulled the flywheel assy, there are (4) screws or allen-heads holding the stator to the bearing end cap. Install the replacement stator with a drop of blue Loctite on each screw/bolt.
Reinstall the flywheel, with a drop of red Loctite on each bolt. Before reefing on the flywheel bolts, reinstall the timing pointer to its original position.
Torque the flwheel bolts to approx 25 ft-lb. I couldn't find a torque spec in the manual but if you check an SAE chart that's about average for a Grade 8 fine-threaded 5/16". The red Loctite will assure the bolts don't loosen up.
Note that if you were to inadvertently move the flywheel and lose the position of the pointer in relation to the flywheel, there's a procedure in the manual to reset to exact TDC.
HTH and G'luck with the repairs.........ed