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1990 seadoo sp pistons
- Thread starter lilpain
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Dr Honda
Well-Known Member
If the engine was cold (and I assume it was) yes... your pistons will have some pay in them. There is at least 0.003" clearance, and since it's an old engine... it's probably higher than that.
The Knocking.... was it at an idle? Or did it get louder as you gave it throttle? Also, was the ski in the water?
2 things... the pumps are known to knock at low RPM's since there isn't enough pressure in the pump to load the impeller.
AND... there isn't much room at the top of the old hulls, and if you have a knock at idle, it could be that the pipe is hitting your seat or hull if your idle is rough or you have a ripped motor mount.
If you have a knock from the engine... it would be from the lower end. (crank and connecting rods) Piston slap is more of a rattle sound.
The Knocking.... was it at an idle? Or did it get louder as you gave it throttle? Also, was the ski in the water?
2 things... the pumps are known to knock at low RPM's since there isn't enough pressure in the pump to load the impeller.
AND... there isn't much room at the top of the old hulls, and if you have a knock at idle, it could be that the pipe is hitting your seat or hull if your idle is rough or you have a ripped motor mount.
If you have a knock from the engine... it would be from the lower end. (crank and connecting rods) Piston slap is more of a rattle sound.
Does the oil tank go down as you ride? always mark the tank the first tank of gas each season - no harm in running some premix the first time to give time to verify the oil drinking. also sometimes the duel air box hits the hull but if it is all the time I think a rework is coming your way soon read here as much as you can and get comfortable with 2stroke service before you remove pistons.
Dr Honda
Well-Known Member
I just pulled the spec on the 587 engine, and a fresh rebuild is 0.008" clearance. (that's huge) and if that engine is pushing 20 years old... you probably have 0.012" or more. Yup... they are going to "rattle", but they wont "Knock."
If you are worried about it... remove the pump and the driveshaft, and then start the engine to see if the noise goes away. Unfortunatly... if it is the engine, it's just time for a rebuild, and as I said before... a "Knock" is going to come from the bottom half... not the top.
If you are worried about it... remove the pump and the driveshaft, and then start the engine to see if the noise goes away. Unfortunatly... if it is the engine, it's just time for a rebuild, and as I said before... a "Knock" is going to come from the bottom half... not the top.
Dr Honda
Well-Known Member
The best thing is pack the crank hole with shop towels to hold the needles from falling into the rotating lower end, on a 650 there will be 34 of them you put into a sandwich bag and move the towels to the other hole, a magnet will be your friend to catch them all.
The pins slide out pretty easy and then you hear the clinkety clink, measure your rod ends cause there are 2 sizes used on the mid 90 650, the 580 may be the same, have you remove the rv cover? you can use a car heater hose clamp to hold the disk in position, marker pens seem to rub off right away.
The pins slide out pretty easy and then you hear the clinkety clink, measure your rod ends cause there are 2 sizes used on the mid 90 650, the 580 may be the same, have you remove the rv cover? you can use a car heater hose clamp to hold the disk in position, marker pens seem to rub off right away.
im in california. im sure its my pistons slaping against the cylinder walls . itook the cover of to take a look a the pistons and move the impeller shaft im not sure whats it calld but it made the pistons go up and down and yes i heard the slapping noise.im not sure what to do. should i just buy the pistons or should i plso buy new sleavs.
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