1993 Merc/Force 90 Sport Jet

[juanrs]

Hello, everyone, I'm new to boating and to this forum. I recently got a 1993 sea rayder and I bored the cylinders to .040" oversized(they were already bored to .030" when i got the boat) I cannot get the boat to idle no matter where my idle adjustment or the air fuel mixture screws are set. Do the carbs need to be rejetted for the larger pistons? It has new fuel pump, pump diaphragm fuel filter, gas, gas pickup screen, voltage regulator, rev limiter is disabled, red stator, cleaned carbs, new plugs, good compression. With the throttle above idle she stays on and also runs good at WOT (around 30mph) but feels like I can get a little more out of it. Also one of the magnets in my brand new fly wheel cracked and fell off, does anywhere here have a magnet that I can buy from them? Thanks for your help in advance.

 

[Frank Acampora]

You can not get an engine to run correctly unless the timing is set correctly AND the carb opening is synchronized to the timing advance. So, re-set the timing to factory specifications and watch the sticky video on synchronizing timing and carbs.

Even at .040 overbore,the added displacement is only around 1 cubic inch. The engine and carbs will never notice the added airflow and re-jetting should not be necessary.

 

[pnwboat]

With a missing magnet, you won't generate the proper stator voltage to operate the ignition system.

 

[jerryjerry05]

If you have gapped plugs.
Run the boat at WOT for a 5-10 min.
Then turn the key off. Don't slow down or move the throttle.
Remove the plugs and check the burn.
Color of the plug.s?