This is kind of a follow-on to Lennky's 7/5 post, and Chris1956's reply, but with an "occasional" twist. Pardon the long history -I thought it might be important.<br /><br />I just completed a tear-down of a 1969 Merc 500 (acquired last year on eBay - never had it running) to see why it would not run - died when giving it gas. I replaced piston #3 (stuck rings) with a used one, and replaced the broken reed valve (also #3 piston). I also replaced fuel pump, rebuilt carbs, and replaced the impeller and lower unit seals. Whew - I've never done anything like this before - it was an interesting experience!<br /><br />Initial testing went well - the motor ran well on a 10-mph limit lake, at various speeds up to the lake limit.<br /><br />Two days later I tested on a larger lake - started a little hard but ran nicely thereafter. I eventually worked up to full speed - it ran as expected at all throttle positions.<br /><br />A couple hours later I tried again - initially it would die moving from idle to any speed, but after a few tries it worked fine, and I could even pull my kids on skiis, which I then did for a half hour or so with no issues. They enjoyed the faster speeds of this motor (as compared to my 40 hp Mark 55).<br /><br />A couple hours later I went out again - it took many attempts to get out of idle, but when it did, it ran fine. Until the skiier fell, then I could not get it to go out of idle without it dying.<br /><br />Next morning - it ran fine at all speeds - I ran it for about 15 minutes, trying various speeds. <br /><br />A couple hours later, I tried again, and could not get it out of idle. Period. Engine would start fine, but would die when giving it gas. I tried many times.<br /><br />The high-speed carbs are fixed jet, the low-speed are adjustable. I did not think to adjust the lo-speed, since the idling worked fine, but based on Chris1956's response to Lennky's post, maybe I need it richer?? Could I have messed up on something with the reed valve/piston replacement? But why would it then work fine sometimes and not others? Any hints on what I need to be looking for? <br /><br />I should also mention that I did see water coming out the telltale the whole time, though not as strong as on my Mark 55. The hose and nozzle are not plugged, and the impeller and pump seal are new. Don't know if there is a problem here or not.<br /><br />Thanks for any input.
For me, things like the kitchen sink dripping always seem to get the priority.