The last two times i have been for a ride my ski has been a bitch,the first time i thought it may have been water in the tank not so, i get to a point (about 1/2 - 3/4 of a tank of gas) where i can keep it just above idle or full nana in between i can only keep it going by pumping the primer.The first time it came right but this weekend a freind had to tow me home with his house boat.THEN i was flushing it out and the revs picked up pulled the lanyard of it still reved so pulled the spark plug leads off still reving its nuts off stoped the bitch of a thing by putting my hand over the intake.The front cylinder (going from the plug)was lean as hell pulled the carbs down but nothing looked amiss.Does anyone have any ideas aside a bomb.?????
dunno bout running on, tho a leaking fuel tap (off - on res) has caused my carb to 'lean out', seemingly unexplainably before...can't fix them only replace
The engine is preigniting the fuel, I have have had this before in one of my previous super jets and one of my mates has the problem now with a JS 550. It could be caused by a small drop of water in the carb which allows fuel to flow even though you werent giving it any throttle. What happens is the small amoutn of fuel causes it to get so lean and the explosion so intense in the cylinders that the heat pre ignites the fuel causing it to rev its head off. You cant stop it using the spark plugs because they are not causing the ignition, the only way to stop it is to suffocate it. Also it will only do it when it is on land as there is too much engine load when it is in the water for it to pre ignite on the small amount of fuel it is getting. You may not be able to see the water in the carb as it could be the smallest drop doing the damage but a good clean out of the carb, filters and tank may well fix the fault. It fixed it on my SJ.
sj Make sure there is no air leaks around carb and reed gaskets etc. I have had i happen on a few skis if to lean it can do it to. Pump primer or choke it, even opening throttle will kill but dont let it run like that as its revving with little to no gas so leaning out big time so if premix you can damage the engine.
check your timing I had this problem and the timing was way advanced. It justed reved to the moon.one day your engine will go bang.
Thanks guys I did find the smallest amount of water in the carbs along with a bit of poo i guess when i cut the filter open and the element was flopping around inside may not have helped the cause. Also did find a couple of shadows on the gasket faces on the manifold?? and I'm going to check the timing even though I'm sure it was an air fuel jobby. Just thought i would ask cause you can never stop learning cheers.
iv had that happen b4 aswell on my old sxi scared the shit outa me when ya cant stop it!! i ended up backing it back into the water, it idled for 20seconds or so then stoped and wouldnt start again.
Its an airleak and you need to find it if you dont then you are allowing un metered air into your engine and i will do damage in time
