i have outboard 83' mercury 135 v6 2 stroke and i am completely out of ideas. it started at the begining of this season first trip to the lake after i replaced the impellor which seemed to be working fine in my driveway. on the lake it would only pump water at a low idle, if i pushed the throttle any farther the check stream would stop and only steam would blast out untill returned to idle.i went home and replaced the impeller again and double checked everything and replaced the thermastats which i found one was missing and the other was seized. the new thermastats seemed to help a little could now idle slightly higher before water would cut out and even when stream was present it was weak. so i checked the impeller again and rebulit the pressure release valve replaced all hoses and checked for blockages using compressed air which seemed to have no problem blowing thru. i put everything back together and this time left both the thermastates out. now it had a strong stream and would increase when throttled up. took the boat to the lake today all seemed well till i went full throttle and again stream stopped and steamed untill i pulled throttle back a little then strong stream came back. SOMEONE PLEASE HELP I DONT KNOW WHERE TO GO FROM HERE!!!!! anyone with any input would be greatly appreciated cause i dont think there is anything left to fix haha at least nothing i can find in the manual.
