Hi there. There are many issues that can affect this. Most have been covered here already. The fins do work although I don't like them. 2 up on a 9' should leap up onto the plane in two boat-lengths. It sounds to me like that motor is not putting out its best. (Of course this is considering that you are two normal sized people) Lets say that you weigh in at 160Lbs each, then the above should ring true. Your comment that the fins made no difference worries me. Please check that you do not have water
between your hulls if it is a double bottom. Could be the bung is out, and as the water
drains you get planing.
Next could you please read the pitch
off the prop, should be something lik 9 3/4 x 10 1/2 or close.
Also, check that there are no problems inside the engine cover. I have come across many silly things. Is it an Enduro or SW series? If it is Enduro there is not much tuning.
Ok lets say all the above checks out, its time to look under the hood
Remove the kill cord
Remove the cover.
Observe the linkages on the RHS of the Carburetter, now operate the choke lever, pull and push it, and see that all the pins are engaged in their slots. Sometimes the choke can be 1/3 shut irrespective of push pull position.
Move on to the timing, observe on the engines RHS (Left as you look at it) there is a window in the plastic start mechanism cover. There is a pointer molded into the plastic. Pull the start cord s l o w l y to see the 0 mark, now by hand, turn it back to -5 degrees. Now, look under the flywheel slightly aft of the pointer, and you will see a white pointer, it moves if you rattle the throttle twist grip, (so you can find it) is it lined up with the other line scored in the crankshaft?
Now, put into gear
, and open the throttle full but OBSERVE all the linkages on the engine RHS. Rotate the flywheel again and see if the white pointer lines up with the same score, and the plastic line should be about 30 deg.
Now look at the carburettor, open and close the throttle while you do, and you will see a quadrant rotating driven by a linkage, look closely and see if the quadrant actually gets to its stop, ie is the throttle getting to wide open?
If that all checks out we need to re-think....
If you want to give me feedback or ask questions, please email
me, I can't check the threads that often...