1990 Superjet lost acceleration after a small wake jump

[misuperjet]

Hello all! Newbie to standups here.

I recently purchased this ski, 1990 superjet. My first standup and first Yamaha. Mostly stock but has an aftermarket ride plate, aluminum pole, aftermarket intake grate.

It ran great for about an hour. I was going in a straight line without doing anything dynamic, went over a 6" wake, ski landed and I heard a light clunk noise. After that it would not accelerate past idle speed. The motor revs up (louder than usual with more vibration) but will not accelerate. It almost feels like a wear ring that is bad (I ride a lot of sit down skis and seems like the same feeling). Once I got it back on the lift, the motor had no problem reving up to clear out the exhaust. From looking at other threads, I was thinking of checking the mid-shaft, impeller, and impeller gap to wear ring. Anything else I should be looking for or checking?

I have not taken anything apart on a Yamaha or a standup before. Only restored 2 97 seadoo GTXs. I know a little bit but sorry if I am not familiar with normal lingo here. TIA for your help!

 

[WFO Speedracer]

Check to see if you sucked something up into the jet pump , but yes it could have stripped the midshaft also

 

[hornedogg79]

Check waterbox for broken baffle.

 

[misuperjet]

Thank you! I will check on those things and respond with what I find

 

[misuperjet]

Just to update everyone on the situation, I took off the mid shaft cover to inspect, looked at the mid shaft bearing and housing, jet drive, impeller, and wear ring (while still on the ski) and nothing! Only some small dry rot on the mid shaft housing rubber. I put it back in the water and it ran just fine. Weird! My neighbor helped me and said he has had that happen before where it will work just fine once you get it out of the water and restart it.

 

[WFO Speedracer]

I still say it must of sucked something up and it spit it out or fell out later. I had a guy bring one in one time and said his buddy rode it and it ran great , so great that it blew his hat off , he turned around to try and find his hat but couldn't , then all of a sudden it stopped pulling , I crawled under it after they left and found the issue , when I called him back I said tell your friend I found his hat .

 

[misuperjet]

That is pretty much what my neighbor said too. Must have spit it out when I started it after I docked it. I have a floating lift so once I got it on the lift I started it to blow out the water and see what the issue was. Must have cleared out from that.

 

[Myself]

Real common. Get some weeds or a small stick up in the pump and lose thrust. When you pull out of the water, the debris just falls out with the water movement from the pump.

 

[WFO Speedracer]

i Had a Seadoo that sucked up a pine cone and it stuck between the blades where you couldn't see it, as soon as I pulled the pump I found it.

 

[mikeljeffon444]

I had bad wheels for mine

Sent from my SM-G965U using Tapatalk