Greetings! I have a 1988 Mercury ELXPTO (With a Sea Ray cowling) 100 hp 4 cylinder - this one runs on 2 cylinders at idle and doesn't have a 'head' per se - the back of the motor has the cylinder that comes to a dome with the spark plug inserted into the dome - no access from the top of the piston there. From the story I can piece together original users water skied with it for about 10 yrs then parked it for the last 20. All 4 cylinders has #120psi compression when I bought it. I rebuilt the fuel pump and accelerator pump - corrected a few fuel & oil lines and it started and ran good on the mufs in the driveway. After rigging it for fishing I took it out for the first time. It started better in the water than the driveway - tatletale worked, sounded great, would like the idle slightly lower but very happy! Took it out for a nice BIG circle gradually increasing speed etc. Turned it off and fished. At the end of the day - figured we'd go for a victory lap - hit the throttle (the wife eventually wants to ski behind it) according to the GPS we got up to 40mph and was still gaining speed (I was Sooo Happy!) when It shut down - acted like it ran out of gas (my old boat's fuel coupler would often come un-done if someone moved belongings around - so I'm familiar with that feeling!) but everything was hooked up - we could not get it to fire anymore. We used the trolling motor to get back to the dock. Home inspection - good amount of fuel, fuel pump working, good spark at all 4 cylinders. #1,3, & 4 cylinders 120# psi #2 cylinder 0# psi! 3 plugs looked shiny & new - #2 plug was black with soot. I won't have time to inspect it for another week but I thought I'd pick your collective brains in the mean time.
Looking at the manuals, on the compression side there's just the reed block and it's gasket, so that leaves the rings and the block that could have failed? From what I've read - it's seldom if ever the reeds. I'm a fairly accomplished automobile mechanic but relatively new to 2 stroke OBs. Do the reeds actually hold the 120# psi or is the compression in the block less? Would the consensus then be that it's probably the rings or cracked block? Any recommendations on further investigation? I believe I read you can remove the exhaust side plate and rotate the crank until the rings are visible via the side ports?
Thanks in advance for your advise!
Looking at the manuals, on the compression side there's just the reed block and it's gasket, so that leaves the rings and the block that could have failed? From what I've read - it's seldom if ever the reeds. I'm a fairly accomplished automobile mechanic but relatively new to 2 stroke OBs. Do the reeds actually hold the 120# psi or is the compression in the block less? Would the consensus then be that it's probably the rings or cracked block? Any recommendations on further investigation? I believe I read you can remove the exhaust side plate and rotate the crank until the rings are visible via the side ports?
Thanks in advance for your advise!
