Why not a motorhead catagory ?

Anyway - any body into boat motors ?

I was helping a friend with his twin 305 1989 Amerosport I/O Boat. His one motor stopped firing - it has new plugs - new coil, rebuilt carb, clean fuel and separator filter, electronic ignition module.

There is no visible reason for it not to start/ignite .

No we have learned there's a spark interrupt system that momentarily stalls the motor when shifting. Its called a "Over stroke system" - we believe ! We checked all the switch's and they seem to function properly.

Yes, strong spark, engine turns freely, fuel flow adequate, compression in range - highest cylinder 150psi - lowest 130psi.

Any suggestions or advise would be appreciated.