Hi, My son has a '97 Seadoo GSX 787 that he lost a rod bearing in. We've replaced the crank, bored the cylinders, camfered the ports, machined the power valves and re-installed everything, including new WSM Platinum pistons at .50mm over.
We really questioned the direction of the arrow on the piston. This engine has the intake and exhaust on the same side. Our Clymers manual said to point the arrow to the exhaust side of the motor, but then had a picture of the pistons with the arrow pointing away from the rotary valve. We installed the pistons like in the picture.
We got it all together and ran it for 1/2 hour in the shop and it was running great. We had added a quart of injector oil to a full tank of gas as the manual said for break in, and had used a lot of extra lube during reassembly, so it smoked a lot for the first 5 minutes or so, but straightened out and was running really well.
When we put it into the water and tried to give it throttle, it just quit. There was no compression in the front cylinder. When we removed the head, we saw that the top of the piston had failed and the ring was destroyed.
I've got all the pieces of ring out of it and the cylinder wasn't damaged and it's been honed again. A new piston is on its way. My question is, did I install the pistons in the wrong direction and have that cause the problem? Which direction should the arrows be pointing? Toward the intake/exhaust or away?
Thanks in advance.
We really questioned the direction of the arrow on the piston. This engine has the intake and exhaust on the same side. Our Clymers manual said to point the arrow to the exhaust side of the motor, but then had a picture of the pistons with the arrow pointing away from the rotary valve. We installed the pistons like in the picture.
We got it all together and ran it for 1/2 hour in the shop and it was running great. We had added a quart of injector oil to a full tank of gas as the manual said for break in, and had used a lot of extra lube during reassembly, so it smoked a lot for the first 5 minutes or so, but straightened out and was running really well.
When we put it into the water and tried to give it throttle, it just quit. There was no compression in the front cylinder. When we removed the head, we saw that the top of the piston had failed and the ring was destroyed.
I've got all the pieces of ring out of it and the cylinder wasn't damaged and it's been honed again. A new piston is on its way. My question is, did I install the pistons in the wrong direction and have that cause the problem? Which direction should the arrows be pointing? Toward the intake/exhaust or away?
Thanks in advance.
