The Magnums have a fairly TIGHT tuning range.

I've found that on a new engine 3/4 turn takes you from full rich to full lean and anything outside of that results in no starts, just an occasional ignition stroke as youve described.

They really do need long four stroke plugs as stated...

Set the needles to slightly more open then recommended.


- Flip the engine over and make sure that fuel gets into the carb...

- Watch to see if the fuel siphons back into the tank ( it should not, or it should do so very slowly at worst ).

- Then try to start the engine.

- If after 2 to 3 attempts it does not start, lean the LS needle in by 1/4 turn and try again.

Rinse lather and repeat until the engine starts at high idle and then work on the HS needle.