1967 Merc60 6HP - Where is Tell Tale

I'm sure this question has probably been answered a million times by you guys, but I couldn't find it in the archives. I'm new here, so that probably says a lot. lol.

I recently bought a small flat bottom with a 67' Merc60 6HP motor. The motor cranks well, but will only idle/run for short times. Sometimes 30-45 seconds, and sometimes a minute or two. If I keep fuel primed every 15 seconds or so it'll run for longer, but inevitably shuts off. I replaced the fuel primer bulb, and ran the motor again in a tank but noticed no water coming out of the exhaust (is that the tell tale?).

Any ideas or information would be great as I bought this boat for my son, and would love to get him out on the water in it.
If I left any information out, just lemme know.
Thanks!

Re: 1967 Merc60 6HP - Where is Tell Tale

I removed the "flush" plug and found it full of sand. I picked the sand out and stuck a water hose to the flush hole until I had a steady stream of water coming out of the prop. Is there a way to access the copper tube or whatever tube the water travels in to make sure the whole system is cleaned out?

Re: 1967 Merc60 6HP - Where is Tell Tale

Full of sand = new impeller BRFORE starting up again.When you have the lower off for the new impeller the water feed line is there,flush it out. I would rebuild fuel pump and see if that fixes your idle/run time.

Re: 1967 Merc60 6HP - Where is Tell Tale

Thanks mr 88,
Is the tell tale on the back of the motor just below the cowling? Looks like a little exhaust port? Also, is there a good way to flush old oil out of the lower unit other than just pumping new gear lube through it over and over?
Thanks!
Chris