sj not hooking up

[chrisdoc0608]

last weekend i rode for abt 5 hrs (2 tanks of gas) as i was pulling back to the ramp, i gave it one more wot before the no wake zone, and i suddenly started to free rev with little foward movement. after pulling the ski out i noticed my reduction nozzle was badly damaged, so i just got a metal one from a friend. i took it out abt an hour ago and went to hit it from idle and it did the same thing, so then i tried easing into it and once i got on a plane i could run at wot no problem. it is the equivalent to burning out down a race track, just not hooking up unless i ease into it. when i pulled it out of the water i looked at the impeller and there is a gap between it and the wear ring all the way around abt the size of 15-20 peices of computer paper (sorry thats the only thing around me that i can use to compare right now) so i am thinking that something like a stick or some trash on the water went through and messed up my wear ring and nozzle. i have a skat trak impeller on it right now, do i need to buy a wear ring for that specific impeller if thats what is wrong?

 

[chrisdoc0608]

here are some pics of the impeller through the back of the ski, notice the gap?

 

[Jr.]

The pump seals on the older SJ's were 2 piece. ( rubber outer with Metal inner ring) Those would seperate & cause an air leak. I'm guessing that is what happened to yours. You will need to update to the newer style seal.
If course there is always the posibility of other damage you didn't see from the first incident.
Best course of action is to remove the entire pump assy & the damage or cause will defintely show it's self!

ski ya, Paul

 

[chrisdoc0608]

i had the entire pump assembly off. i didnt see any damage, what seals are you talking abt? the only seal i saw was a rubber one that went inbetween the intake grate and around the outside of the impeller housing

 

[chrisdoc0608]

ok i pulled the pump again and here is what i am seeing. there are dings on the cutting edges of the impeller, the seal is good, and i believe the space in the wear ring is ok. im going to try and knock down the dings a little with some light grit paper and see what happens.

 

[SuperJETT]

It definitely sounds like a pump seal problem. You need to really look at the seal, see if it's dried out, or possibly you weren't able to get the pump far enough forward for it to seal against the pump shoe. I've also had a cracked pump shoe before.

One way or another, you're sucking air from the pump cavity into the front of the impeller and it's hard to find the problem sometimes because you're looking at pieces, not seeing it while running.

 

[chrisdoc0608]

so you guys dont think that it is the dings in the impeller causing cavitation?

i just rode it for abt an hour after grinding down a little on those dents, it seemed to help a little. it ran ok as long as i had it above abt 1/3 throttle, but bottom end still sucked ass

were can i get the pump seal anyway? if its the thing that goes between the pump and the pump shoe, it looks fine to me...

 

[chrisdoc0608]

bump... what is the pump seal and where can i get one? you guys sure that the dings in the impeller couldnt cause cavitation? they are on the cutting edge...

 

[stanton]

your impeller looks pretty trashed!
did you take off the pump shoe yet?

 

[chrisdoc0608]

isnt the pump shoe like glued to the hull? it doesnt appear cracked anywhere though.

 

[sfab]

i got the same bottom end problem right now and my impeller too have a gap of 0.04-.05" from tip of blade to wear ring. it should be at max 0.02". it dosnt hook at all off idle but pass 1/4 throttle, yes. my seals are in good shape too, so im pretty sure its the impeller. anyway i got a new skat-trak swirl on the way, hope it will cure the problem!! :biggthumpup:

 

[onesojourner]

your impeller looks pretty trashed!
did you take off the pump shoe yet?

??? take off the pump shoe? the pump shoe is not something you take off unless its is broke. its a huge pain. look and make sure its sealed up good but don't take it off. grease the packing when you put the pump back in. thats the rubber that goes between the shoe and the pump. that prop does not look that bad. I would not think it would cause what you are experiencing.

 

[chrisdoc0608]

ok well if i dont see any broke areas on the pump shoe, and i am pretty convinced that my packing as you called it is good as well, do i use just waterproof grease on it? if these problems are not caused by my impeller, then what the hell could be causing them? everything was fine b4 i blew that reduction nozzle to peices..... any help would be greatly appreciated, i would like to fix this b4 the weekend so i can hit the beach with it.

 

[stanton]

idk looked like it was held on by 4 screws

noticed any new vibrations?
maybe your impeller is tweaked

 

[onesojourner]

its help in by 4 screws and lots of glue. provided its stock. look for anything that could be sucking air in. the pump shoe should be all sealed up. double check that. I am no expert on props but those little nicks I could not see doing anything extreme. is the prop installed correctly?

 

[chrisdoc0608]

here are more pics:

notice the ding on the stator vien

and another ding on the stator vein

is this the seal you guys were talking abt? there was one mark on it where it had a little wear, not torn all the way through though, just a knick (right below my thumb)

wear ring and the seal installed, i believe this is the correct way, it fit a lot better than the other way...

here is a pic of the new nozzle mounted, it matches fine with the veins.

as for the pump shoe, i looked it over top to bottom and didnt see any cracks anywhere... should i just silicon it up at all the seams just to say i did?

Thanks for the help guys

 

[sfab]

if you can stuff 15-20 sheet of paper between the impeller and wear ring, then its out of specs. 15 sheets equal to 0.045" and the limits is 0.025". you should replace your impeller and/or wear ring. chk the image ive included

 

[chrisdoc0608]

thanks for the specs, i am going to go measure the clearance in just a minute. this would verify what i thought happened if it is out of spec. i know i sucked up something nasty bc it absolutely destroyed my nozzle, so i think it may have grinded down the wear ring as well, but i will find out soon enough.
thanks man

 

[chrisdoc0608]

wow! i really missjudged that. i just measured the gap, and it is less than .016 almost all the way around, there a was one point where the .017 fit. so i guess that is good.... should i try to silicon my pump shoe?

 

[chrisdoc0608]

bump to the toppppppppp i just need to know if siliconing my pump shoe is a good idea, i will be trying to get another seal to try out tomarrow bc i cant get one on order until friday.