Hey guys, I have a 1970 Merc 800 Thunderbolt and I started it up for the first time since I bought it and did not see any water spitting out above the waterline. I had the engine on a stand using ear muffs, I didn't run the motor long at all, I am hoping that the water pressure didn't get high enough where it didn't exit out of the water outlets. If my water pump is toast, can I just reverse the pump and use it? I have heard that from a few people. Thanks
Re: 1970 Mercury 800 Thunderbolt water pump question?
Do not reverse the impeller. It will surely fail if you do that. Replace the impeller, wearplate and the two gaskets. Also change the gear oil.
On the flusher device water should exit the gratings above and behind the prop, as well as thru the prop. Water may also come out the square holes at the base of the powerhead. The telltales clog easily.