650/X-2 89 650sx issues

B

burley910

Location
North Carolina
just picked up the ski about a month ago. Ive been having fuel issues and cant figure out the problem. when its on the trailer, the ski doesnt want to turn over. in the water, however, if you prime it 3 pumps it will start up and go. it will run like this as long as the throttle is about full butt once it lowers rpm's, it bogs out. pump it 3 more times and it will get going again. rode if for about 2 hours yesterday like thise. once i pulled the ski and hooked it to the hose, it started up after having to prime it and at mid throttle it was cutting out. sounded like the noise when its "dolphin'ing" out of the water. stock single mikuni with a mariner pipe. no other mods. any ideas on whats happening?
 
B

burley910

Location
North Carolina
carb is clean. jets are clean. it's a KeiHin single carb with a 125 main jet and 48 idle jet. not sure if these are the stock jets for the carb? also the low was turned out 1.5 and the high was turned out 2 rotations.

the diaphragm looked to be fine, however the circular metal plate was coming off and it seemed to be sitting higher on one side than the other. not sure if that means the diaphragm is bad even though it is not ripped.

the reeds weren't brittle or cracked but there was a gap at the top where they weren't seeting right. figured that may cause more of an idle issue than anything which isn't the problem at hand.

checked compression and its 150 in both cylinders. did notice also that the plug on the front cylinder had a crack completely through the ceramic part which is still baffling me how that would have happened as it wasn't tightened too much.

not sure where to go from here. any input?
 
Last edited:
Wilke

Wilke

X2 stole my life
Location
Indialantic, FL
carb is clean. jets are clean. it's a KeiHin single carb with a 125 main jet and 48 idle jet. not sure if these are the stock jets for the carb? also the low was turned out 1.5 and the high was turned out 2 rotations.
Click to expand...
125 main / 48 idle is the stock jetting, but the screws are set much too rich for a basicly stock engine. Start with the low 1 turn out and the high at 3/4 turn out. It will most likely take additional tuning from there to get it dialed in. This is a good read on carb tuning... http://www.groupk.com/tec-carbs98.htm.

the diaphragm looked to be fine, however the circular metal plate was coming off and it seemed to be sitting higher on one side than the other. not sure if that means the diaphragm is bad even though it is not ripped.
Click to expand...
The plate should sit flush and the diaphram doesn't have to rip to be bad, if it gets stiff and a little brittle it needs to be replaced. Does your carb have an external fuel pump or is the pump built into the carb?

did notice also that the plug on the front cylinder had a crack completely through the ceramic part which is still baffling me how that would have happened as it wasn't tightened too much.
Click to expand...
That is a new one for me, never seen that. you should put some new plugs in regaurdless, use NGK BR8ES.

Sounds like your problem is all related to the carb and tuning, get that sorted out and I think you'll be good to go.
 
B

burley910

Location
North Carolina
Yah the fuel pump is external. The diaphragm isnt hard or stiff but ordered a new one anyways. Also got plugs and adjusted the carb. Had to get a new throttle cable as well. Flipped reeds over so they are now seeting at the top. Should know by tonight/ tomorrow how it is running
 
You must log in or register to reply here.
Top Bottom