1976 25hp evinrude flywheel problem

[nick271]

G'day guys hoping someone hear can help me as I haven't been able to find any info on this
I have a 1976 25hp rude running and a 1978 25hp rude spare parts motor
Iv damaged the flywheel on my 76 so pulled the flywheel off both motors the one off the 78 looks slightly diffrent on the inside im just wondering will the 78 flywheel work on my 76 or will it throw the timing off?
And well im hear the reason I was pulling the flywheel off the 76 and damaged it in the process (bastard was stuck on real good) I hit a log on the water jumped the motor hard and it died on the spot when trying to rest start it wouldn't go I have compression, spark and fuel upto the plugs well trying to start the motor it was blowing black smoke out the exhaust and every now and them would backfire out the exhaust this lead me to belive the timing was gone so I pulled the flywheel to check the woodruff key on the crank shaft but the key is still intact would there be another reason for the motor not to start and backfire?
Added note the motor is normally very easy to start

 

[Nordin]

Different flywheels cause different ignition system.
76 has the low tension system with points and a drive coil under the flywheel.
78 has CDI ignition with a power pack.
Sensor coil and a charge coil under the wheel.

 

[nick271]

Cheeres for the info I'm guessing that's a no I can't use the 78 flywheel on the 76 motor then

 

[saltchuckmatt]

I believe you can you just have to swap everything with it.

 

[racerone]

??----Is the taper on the 2 crankshafts the same , yes or no ?-----Is the bore / stroke the same between these 2 motors ?

 

[nick271]

I believe you can you just have to swap everything with it.

Well that sounds like an idea just swap the entire magneto set up might be doable but the 76 is a basic ***** no power pack or power coils I could test the ones on the 78 but from what iv been told it hasn't been running for 20 odd years l snaped it up for 100 bucks thinking the years were close enough looking into everything now I think my 76 was the last of the dinosaurs the 78 seems very different

 

[nick271]

??----Is the taper on the 2 crankshafts the same , yes or no ?-----Is the bore / stroke the same between these

 

[nick271]

I don't belive these old 2 strokes have tappets as for borehole I'm still trying to find out this info aside from pulling them both apart and taking a tape to them im unshore

 

[saltchuckmatt]

Swapped out and modified for a electric start and pull start. Didn't happen overnight.

Much to learn.