Appreciate all of the input...The saga continues. I was getting 62MPH (on digital speedometer)...that slowly became 58, 55, 50MPH. I pulled back into the dock, idle was low, loss of power and a knocking in the motor. Checked compression - 125 in the front cylinder and 101 in the rear. This engine was just rebuilt under a no fault warranty because the front cylinder had failed. I also had the motor and carbs installed and everything gone over by a local shop (that is very good). I am at a loss for what to do. Do I send it back for a 3rd time of go somewhere else. Any other ideas? I can not do the work myself anymore.
if your engine was just rebuilt, compression should be 150psi or better. Check the O-ring on your compression gauge, Hand tight should be good, but if in doubt, get a good grip on it, or snug it with a wrench, and Always use anti-seize with aluminum heads.
yes, adding 2-stroke oil to Your fuel will make it rich, and plugs will be wet & black, so will your exhaust manifold and exhaust System be, just like your plugs. And how did you add the oil to your fuel? The correct way is to put 2.6 oz full synthetic per gallon, in your gas can first, then at the pump, add fuel, the exact amoun, shake well and pour in tank. If you just poured the oil directly into your tank, it’s not going to mix well.
With a mirror and a light, check your injection pump calibration. The lines should line up perfectly.
your low idle could be from weak spark, due to fouled plugs from too much oil. I would double check that compression, (both plugs out and wires grounded on the posts bombardier puts on their engines just for this purpose)
and if it IS, as low as you claim, take it back to the shop. one more thing...
when you pull plugs to see how it’s running, ride it, wide open first for 5 min or so, then shut it off and pull the plugs. If you have to idle through the harbor at 5mph for 10 Min to get to the launch ramp, you’ll get black oily plugs every time. Take a spark plug socket, or 13/16” open end wrench with you, and slide the seat back and do it while onboard the ski. You will get different results, but as long as you have pre-mix in your tank, it’s going to run too rich.
