Evinrude 1999 4-stroke 9.9. Trying to get this to run of the boat. On the boat it was electic start and hooked into the boat. Noticed the plug from the boat had a mating plug which was intended for this purpose. Plugged them in and used a charger to fire it up. Started up and idles but whenever I tried to open it up it will not rev up. Is there some reason it will not run out of the boat? Seems the spark may be weak or some other limiting factor.