Fx1 power fade.. ?

[mk1]

Hey guys , my ski has developed intermittent power fade when wave jumping or pushing it hard in to the turns etc. It has the standard carb & engine setup. I fitted new plugs , stripped & cleaned the carb + fitted a carb rebuild kit , but this did not make any notable improvement. It only loses power for 2-3 seconds , but that's enough to lose balance and splash... ! Anyone have this problem , & how did you sort it.... Thanks.

 

[amitchell]

From the SBN manual

The "Left Turn Syndrome"
You will find in all instances that your watercraft will turn more easily to the right than to the left. The reasons are basically simple. First, engine torque constantly places pressure on the hull to turn right. If your engine's performance is marginal, you can notice a dramatic falloff in power in a hard turn. This power falloff can't always be blamed on the engine, being over-propped can also cause the engine to slow enough to fall off its power peak. An engine with a peaky power curve is especially susceptible to a very dramatic power loss in a hard left turn. Most recently, with the increase of Sport and Runabout racing, there has been a marked improvement in hull design with a dramatic increase in "G" forces encountered while turning: over 2.5 G's. In some instances such a hard turn can cause momentary loss of power due to fuel starvation in the carbs. Jetting changes cannot correct this situation, the best solution is to rotate the mounting of the carbs 90 deg, so that their throttle shafts are perpendicular to the crankshaft axis rather that parallel. To date, this solution to the problem has been 100% successful.

 

[mk1]

From the SBN manual
The "Left Turn Syndrome"
You will find in all instances that your watercraft will turn more easily to the right than to the left. The reasons are basically simple. First, engine torque constantly places pressure on the hull to turn right. If your engine's performance is marginal, you can notice a dramatic falloff in power in a hard turn. This power falloff can't always be blamed on the engine, being over-propped can also cause the engine to slow enough to fall off its power peak. An engine with a peaky power curve is especially susceptible to a very dramatic power loss in a hard left turn. Most recently, with the increase of Sport and Runabout racing, there has been a marked improvement in hull design with a dramatic increase in "G" forces encountered while turning: over 2.5 G's. In some instances such a hard turn can cause momentary loss of power due to fuel starvation in the carbs. Jetting changes cannot correct this situation, the best solution is to rotate the mounting of the carbs 90 deg, so that their throttle shafts are perpendicular to the crankshaft axis rather that parallel. To date, this solution to the problem has been 100% successful.

Ok , but that throws up a few questions. Are they suggesting that the carb is rotated 90 deg. clockwise or anticlockwise. Is there a mounting kit available for same , as throttle & choke cables will have to be re located , air intake will be lower & on the side of the carb. (water intake issues) , + will the old mikuni carb. be happy to work on its side... ?