Hi, I have a 1995 Kawasaki STS 750 with a new SBT engine. It way past break in, and while it runs smoothly, it is way short on power and will barely make 5600 rpm at wot.
New sbt carb kits, rebuilt fuel pump, clean tank ect. This ski struggles to get out of the water with two medium size riders, and something in clearly wrong.
While I am no expert, I rebuilt a Polaris slt 700 (3 seater, about the same size ski and engine) at the same time, and it screams, has good piston wash, responds to tuning, nice brown spark plugs, and so forth, with virtually no tuning.
Clues:
To get something that looks like piston wash, and avoid a low speed hesitation, I am turning the low speed screws out 1 1/4 and the high speeds out about 3 turns-way over factory specs. If I use the factory settings It sure does not seem like I am getting enough gas though it, the piston crowns seem dry and carbon coated. The single fuel pump has been rebuilt, ski starts like a dream with just a bit of choke.
Pop off: well I tried to adjust this, used some lighter springs, and the ski would not do anything but idle. I put the stock springs back in and it runs and starts great, just low on power and rpms...
Plugs: I noticed some light gray coloring on the insulators, but for the most part they stay pretty clean and wont do much of anything worth looking at. I have changed them, done plug chops, and pulled and adjusted the carbs so many times I cant even count them, the ski just does not seem to respond much to what i do.
Pump: I have noticed some vibrations when I turn one direction under power that the Polaris does not do. I have not done much but look at the impeller, looks clean and not beat up, but I do wonder if some condition can exist with a pump that soaks up a lot of power and rpm from a ski? I have assumed that a worn out pump usually means a ski that revs high but just does not go forward like it should My Kawasaki hooks up and goes, just seems weak.
Fuel Pump: Is there some test for these pumps, like measuring output on the return lines?
Anyway, I am thinking a pressure test of the engine is my next move, any other ideas?
thanks for any help.
New sbt carb kits, rebuilt fuel pump, clean tank ect. This ski struggles to get out of the water with two medium size riders, and something in clearly wrong.
While I am no expert, I rebuilt a Polaris slt 700 (3 seater, about the same size ski and engine) at the same time, and it screams, has good piston wash, responds to tuning, nice brown spark plugs, and so forth, with virtually no tuning.
Clues:
To get something that looks like piston wash, and avoid a low speed hesitation, I am turning the low speed screws out 1 1/4 and the high speeds out about 3 turns-way over factory specs. If I use the factory settings It sure does not seem like I am getting enough gas though it, the piston crowns seem dry and carbon coated. The single fuel pump has been rebuilt, ski starts like a dream with just a bit of choke.
Pop off: well I tried to adjust this, used some lighter springs, and the ski would not do anything but idle. I put the stock springs back in and it runs and starts great, just low on power and rpms...
Plugs: I noticed some light gray coloring on the insulators, but for the most part they stay pretty clean and wont do much of anything worth looking at. I have changed them, done plug chops, and pulled and adjusted the carbs so many times I cant even count them, the ski just does not seem to respond much to what i do.
Pump: I have noticed some vibrations when I turn one direction under power that the Polaris does not do. I have not done much but look at the impeller, looks clean and not beat up, but I do wonder if some condition can exist with a pump that soaks up a lot of power and rpm from a ski? I have assumed that a worn out pump usually means a ski that revs high but just does not go forward like it should My Kawasaki hooks up and goes, just seems weak.
Fuel Pump: Is there some test for these pumps, like measuring output on the return lines?
Anyway, I am thinking a pressure test of the engine is my next move, any other ideas?
thanks for any help.
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