Re: Mariner 150hp v6 (early 80s) piston
#1 piston doesn't travel?<br /><br />You're lucky there isn't a new hole in the block to look into and see why. I hate to be the bearer of bad news, but bro. you need to clear off the work bench for another tear down of that powerhead.<br /><br />///<br /><br />The hole in the water pump body; it is to secure a old style rubber gromet that holds the metal tube running down inside the mid-case in some applications. <br /><br />If your water pump body doesn't have a gromet (new ones will work, but don't have the little 'nub' that fits in the hole), or 3-4" plastic tube that guides the metal tube into it--<br /><br />you've got trouble. that is what seals the water coming out of the pump and sends it up through the 1/2 inch or so metal pipe to the powerhead for engine cooling. <br /><br />If water isn't coming up (under pressure) from the pump into the powerhead, but rather is just blowing out into the mid section and then finding it's way out the prop hub with the exhaust gases, that would be a good place to look and see why you're blowing up or burning out the powerhead.<br /><br />If you don't have a real firm pressure of hot water coming out the peeee hole or bypass vent--<br />within a few seconds of the engine being started, that may well be your problem.<br /><br />Something I've done more than once was to just miss getting the metal tube set into water pump body. I caught it before I blew an engine--- but its easy to do never-the-less.
