Hope Now I Will NOT Blow Up

[BigDaddy]

Piston 1 is where the "tick" sounds like its coming from, 125 psi.
Other 5 pistons are at 135 psi. I syphoned all 50 Gallons out and have mixed 10 Gal worth. I was told to put an ounce of oil in each cylinder and turn the engine over (to circulate the oil) after doing that 3 times the "tick" has gotten quieter, but still I worry.

[THEFERMANATOR]

Sounds like a smeared piston. Reduced compression with a tick is a sign of a smeared pistom in the ring area. Haven't ever been in one of them old YAMAHA's, so I'm not sure if you could snake it out without splitting the case. If you could get it out without splitting it, you could do a light honing to clean the aluminum off the cylinder and replace the one piston to get it running again for awhile. On an old outboard like that I wouldn't personally sink alot of money into it since you don't know the history on it. Could be able to do just a piston for $200-300 if it isn't in that bad of condition inside. If it's all slated up from years of saltwater useage, then it can get expensive when you have to hot wrench everything apart.

[macojoe]

Been there done that!! I had 1989 Yamaha 175 and the injection pump let go, sounds nasty when you are going along!!
I really nursed it along to get home, just idle all the way! Comression in one cylinder was junk and needed one pistion. I sold the motor and bought another.

fix it and get rid of the oil injection!!

[bradford]

Another case showing the merits of premixing.

[BigDaddy]

Well the first thing I did was rip out the oil tank. Second thing I did was syphon out all the gas (50 Gals), mixed it up and poured it back in. I shot some video with sound last night so you could hear what it sounds like. Im gonna start a new thread with the video tonight.
Firm believer of B.O.A.T (break out another thousand)