Mercruiser 140 timing & points

[RandyJ]

I'm kinda guessing at things with this 1976 Merc 140 since my stern drive book doesn't cover this older model. What is the correct timing setting BTDC? What is the correct point gap specification? This is my first inboard or i/o. I love the boat but it is giving me fits. First time out the point hold down screw stripped & I had to improvise with a larger screw in the same hole. Next day I spun out a coupler. I finally got it all together after a few other problems and it was doing great. Went fishing last night and apparently left the live well pump running while I went indoors for 2 hours. SUNK THE **** Thing. Now I've still got to get the water out of cylinders, distributor & oil pan... I got 3 gallons of water out of the gas.... bummer.

 

[Trent]

Re: Mercruiser 140 timing & points

The 140HP is 6 Degrees BTDC @ 650-700 RPM. Plug gap is .035. Breaker point gap is .022 and dwell is 28-34 degrees. Breaker point spring tension 19-23 OZ. Preliminary Idle mixture 1.25 turns.<br /><br />Pull the plugs NOW. Spray oil in the cylinders!! Drain the oil. Spray WD40 all over the place! Hope the starter is not toast? Good luck!!

 

[RandyJ]

Re: Mercruiser 140 timing & points

Thanks for the reply Trent. Fortunately I never attempted to crank the baby before going to work on it. I got 3 gallons of water out of the gas tank added some STP gas treatment, drained the oil pan which had another 2 or 3 gallons of water in it. Pulled plugs, cranked it over and plenty of water rocketed out of it. Without reading this post I squirted WD40 in the cylinders and bumped it over a few times before winding it over several times. I added some STP and cheap motor oil to take it out for a run in the next couple of days. I put it on a hose pipe and it took quite a bit of cranking but once it hit more and more it finally cranked without much problem, just a little starting fluid. Once it got going it now cranks with just a bump of the starter and runs fine. I think I saved the baby without much trouble and after a good run on the lake and new oil filter & oil change will be ready for the rest of this season. I'll probably be on the lake in November if the water is not too low. Here the water fluctuates 30 ft on Smith Lake, but it is super good water for recreation.