Hi i recently purchased a 1965 evinrude sportwin 9.5 Hp outboard. I got the motor which had supposedly ran the year before however it was obvious it had not ran in years on closer inspection at home. The motor refused to run at all so i did a total rebuild on the carb by cleaning all openings and jets with a small wire than blowing it out with compressed air and finally carb cleaner, everything is in order an working properly. next I fixed a problem where the reed valves were stuck open with debris. I also cleaned and checked the fuel pump which seemed to be immaculate. Finally i put new gas lines all around. The motor started and idled perfectly in a bucket so i was convinced i had it fixed however when i took it out on the seaflea it ran great at slow speed however when the throttle was opened up it was as if the motor was running at half speed, it did no more than 8 of 10 mile an hour. I proceeded to check that the throttle was opening full which it is and that the timing advanced all the way which it also is, i then checked that it was getting fuel by pumping the primer bulb (no change in speed) and finally I made sure the vent was open on the gas tank. The engine gets lots of Sparc however i proceeded to pull the fly wheel. The points were ok however i think the previous owner had gaped them with a dime, I gaped them to the factory .20 the motor still continues to act the same. all i can think is for some reason when it reaches a certain it drops a cylinder (possibly due to a bad coil sparking to the flywheel)? however the coils looked good. the previous owner must have had the same idea as me because all the wires and connections were warped in electrical tape. the obvious next steep is to replace the coils, however that's fairly expensive and before i do id like to now if it is likely the problem. the final thin is iv'e noticed that ir you push the drive shaft side to side you can feel a small but obvious clunk which Leeds me to believe that there's some wear on the main bearings, could the motor me sucking air through there? and would that cause the lack of power? the last thing is the motor has lots of compression. thanks for reading any input is great! all post some pictures of the coils but they do look really good.
