1997 seadoo gtx 787 motor.

[randy3489]

my name is Randy, i have a 97 seadoo with a 787 motor, i recently acquired this ski and replaced the wear ring, very shortly after it burned the number one cylinder up (#1 meaning closest to magneto) due to a frayed oil injection cable. now 4 weeks later after the oil block off and one trip to break it in. my second trip to the lake it ran terrible and finally after the struggle keeping it running it just quit like the lanyard just came out, it would no longer turn over or anything. after 20 mins sitting on the water my friend showed up with a boat and it just decided to turn over again (no start)???????

i have replaced the plugs, cleaned carbs, no grey fuel lines, oil bath is correct as far as i know. the motor is excessively noisy when turning over, i have fire but doesnt seem to be great, 140psi #1, 145psi #2, engine spins fast. i cant get it to crank with starting fluid with the spark arrestor removed. i cant get a beep when i attach the lanyard "most of the time". and fuel is good condition. sorry for grammar i was in a hurry. all help is greatly appreciated. i beleive i have covered pretty much everything i am just trying not to remove the engine again, lol.

 

[Dr Honda]

Well... the "Sometimes" beep is probably from a bad beeper. I've replaced them on every ski I've owned.

When the new engine was installed, did it run properly at all? If not... the rotary valve could be set up wrong. Also, since you are running an oil block off... how are you feeding oil to the rotary valve gears?

 

[brandon32689]

What he said and also starter fluid is not good for 2 strokes.

 

[randy3489]

i still have the oil tank in the ski with the lower line connected to the engine case below the carbs. and other line is blocked off.

 

[brandon32689]

Well on the other side of the engine is supose to be the rerun line going to top of oil tank if that's missing it would just poor all the oil out into hull.

 

[Dr Honda]

Well on the other side of the engine is supose to be the rerun line going to top of oil tank if that's missing it would just poor all the oil out into hull.

Sort of...

I think he is saying the return line is plugged.

If that is correct... you may not have any oil in your rotary gears. (or very little) The rear port is higher than the front. SO... you would only fill the rotary valve gear case to the top of the bottom port, and trap an air bubble in the cavity. AND... since the gears are on the top half of the case... It sounds like you are running the gears dry, and I have a bad feeling that you destroyed the gears... and that's why it's not running.

The feed, and return lines need to be hooked up to the tank to keep the gears lubed, and cool.

 

[randy3489]

i have a bad motor from my parts ski, if i pull the motor out of this, would i be able to swap these rotary gears? no special tools/ knowledge, ect...?

 

[randy3489]

by-the-way you are both a great help! thanks a lot!

 

[Dr Honda]

If you chewed up the gears... the engine will need to be split, and cleaned out. So... yes... you will need some special tools, and a factory service manual.

BUT... before you condemn the gears... check them. (since we aren't there, we can only guess at things) Pull the carbs, and look down at the valve. Make sure it's rolling smoothly with the engine.

 

[randy3489]

just pulled the carbs off, the valve started to turn but it quit. is there anything i should know going into a rotary valve motor i am very familiar with outboard marine motors but i haven't seen an RV system before, it doesn't seem to be very intimidating. any thoughts would be great. i wont be working on this until saturday so please don't be shy. Thanks in advance!