1972 Evinrude 25202R 25 HP Flywheel question - # magnets 1 vs. 2, does it matter?

[jjb996]

I recently picked up a 1972 Evinrude 25202R 25 HP outboard. It didn't run so we pulled the flywheel which was stuck and cracked in the process. We removed the rest of the broken flywheel base off the shaft with a dremmel where the key was so it didn't damage the shaft. Looking for a replacement I see the same part number being used all over the place yet they look different than what the diagrams call for. The original flywheel that was removed has only one magnet, some show two in pictures and the one that we ordered from salvage came with two. Will the one with two magnets work? The motor has two sets of points, condensers, and coils. Part number on the drawings shows flywheel 580866. The broken one has two markings, one on the casting underside 581060 and one on the teeth 315840. the salvage one sent to me that has two magnets doesn't have any casting markings I can find, someone wrote on the top with pain pen 73E20 which I assume to be year and HP. Please help!!!

 

[jimmbo]

I think is has to do with whether or not you engine has the single magneto coil ignition system or the older more common 2 ignition coil ignition. A single coil system needs two magnets, while the two coil system uses only one magnet
The 72 used the two coil system, and in 73, OMC changed it to the single coil system. Both systems use 2 sets of points and condensers. When I say single/two coils, I am referring to the number of coils under the flywheel. The single coil system also has two coils on the block/cylinder head from which the spark plug wires originate from

Whether or not the later flywheel can be used on the earlier motor, I can't answer that. F_R might be able to answer that

 

[F_R]

As far as I know, the two-magnet flywheel can be used on motors with two coils under the flywheel, but not the other way around. Disclaimer: I've never actually done it, but see no reason why it won't work.

JFYI, older system was the OMC Universal Magneto and had two coils under flywheel and one magnet in flywheel. Then in 1973 the OMC Lo-Tension Magneto appeared on select model(s) and had one driver coil under flywheel and two magnets.

 

[jjb996]

Thank you for the replies. New points, condensers and two new coils were installed. We now have spark where we didn't previously however we still can't get the engine to want to start. No hint of it wanting to start. We have fuel, verified that, and as I said spark. Not sure if the issue is related to the flywheel with two magnets or not? I would think if we had spark it would catch and if there was a problem it would at least attempt to start or run just possibly not properly. Any ideas or anyone out there who has used a 2 magnet flywheel on a setup like this where it originally had one magnet on the flywheel?

 

[54bobby]

did you link and sync the carb? points at 020? and installed correctly?

 

[oldboat1]

Measure the spark:

 

[lindy46]

Measure the spark:

Spark must jump 1/4" gap in the open air. If you just checked spark at the plugs in open air, not good enough as compression in the cylinders changes things. By the way, did you check compression?

 

[RCO]

Earlier this summer I swapped in a universal magneto to a 1974 25hp that had the low tension setup with two magnets. It ran perfectly using the original two magnet flywheel with the old style coils like yours .