Another Jetrib Victim...

[CMJ]

Yup, another Avon Jetrib with the 'swollen tunnel' issue which has caused the impeller to lock solid in it and I've read much great advice on here on how to fix it - problem is, how do I get to the offending part?!

BTW it's a 2006 seasport sc320 (2-stroke).

So, I've removed the steering/reversing bucket bits at the back and then I've undone the 4 long M6 bolts that hold the sandwich of 4 castings together, and the 4 short M10 bolts that anchor two of the castings to GRP BUT I can't split the Aluminium castings due to corrosion between them (not helped I'm sure by the absence of some sort of gasket). I've bashed and bashed them pretty hard with a hyde/copper hammer but to no avail.

So any advice would be great on how to split these before I end up putting some holes in them with my hammer (either unintentionally or not )
Cheers

 

[aquapower]

Yup, another Avon Jetrib with the 'swollen tunnel' issue which has caused the impeller to lock solid in it and I've read much great advice on here on how to fix it - problem is, how do I get to the offending part?!

BTW it's a 2006 seasport sc320 (2-stroke).

So, I've removed the steering/reversing bucket bits at the back and then I've undone the 4 long M6 bolts that hold the sandwich of 4 castings together, and the 4 short M10 bolts that anchor two of the castings to GRP BUT I can't split the Aluminium castings due to corrosion between them (not helped I'm sure by the absence of some sort of gasket). I've bashed and bashed them pretty hard with a hyde/copper hammer but to no avail.

So any advice would be great on how to split these before I end up putting some holes in them with my hammer (either unintentionally or not )
Cheers

This was a big problem with Kawasaki jet skis with early models, There is a good machine shop in sheffield who I have used a few times and its probrably best to give Alan a call as his advise is allways good and you can send the pump to him for repair.

www.jetshed.co.uk

Tel 01142 477141

 

[jfm]

Yup, another Avon Jetrib with the 'swollen tunnel' issue which has caused the impeller to lock solid in it and I've read much great advice on here on how to fix it - problem is, how do I get to the offending part?!

BTW it's a 2006 seasport sc320 (2-stroke).

So, I've removed the steering/reversing bucket bits at the back and then I've undone the 4 long M6 bolts that hold the sandwich of 4 castings together, and the 4 short M10 bolts that anchor two of the castings to GRP BUT I can't split the Aluminium castings due to corrosion between them (not helped I'm sure by the absence of some sort of gasket). I've bashed and bashed them pretty hard with a hyde/copper hammer but to no avail.

So any advice would be great on how to split these before I end up putting some holes in them with my hammer (either unintentionally or not )
Cheers

Only just seen this Chris and you've prob fixed it by now. But FWIW I have done this repair on both the 2 and 4 strokes, though my memory of it is a bit patchy

In the 2 stroke, there is inside the sandwich of 4 castings a stainless steel liner tube isn't there? I think the aluminium corrodes against this liner, pushing it in, so you get high spots on inside of the jet tube and a jammed impeller. That's my rough memory of it anyhow.

I bodged it. I decided that I couldn't get the sandwich apart and remove the liner, and that if I did the problem would recur. So I just removed the impeller/shaft out of the tube and angle ground 2mm off the tip of each impeller blade. It then worked fine. Of course you lose some thrust because this bodge allows vortexing at the impeller tips but it felt like less than 10% to me and I didn't care, and the repair lasted ages.

When grinding the tips I suggest mark/scribe them carefully first with a tool made up for the job, with a guide that runs along the blade tip. Then you are sure to take off the near-exact same 2mm off each one. Don't guess it!

 

[CMJ]

Only just seen this Chris and you've prob fixed it by now

Not yet actually John.....yep I remember how you fixed yours but still thought you had to split the sandwich (so to speak!)......didn't realise you could get the impeller out otherwise.

I want to replace (or repair) the bit with the s/s liner in it (your memory serves you well and it makes sense what you've suggested in the past about the Al casting swelling due to the corrosion and then causing the liner to bulge)...I'm hoping I'll be able to remove the liner myself (by chucking relevant bit of sandwich in oven knowing Al expands quicker and then knocking s/s bit out) and then tidy up the casting before popping back in.

I'm a bit of a speedfreak and had already noticed a slight drop-off in performance
Well, a-hem - I say speedfreak but I haven't had the balls yet to launch it into a 360deg spin at top speed yet as you've said you have - just working up to it

The drop in performance before it seized totally was prob due to the impeller beginning to rub on the housing - I could hear it on start-up! As I'm keen to get the performance back I'm not too keen on filing the tips of the impeller - although as you say, any fix will probably be temporary anyway due to such a crud design.

Anyway, just trying to get hold of the engineer at Ron Hale who I hope will be able to advise me on how to split the sandwich - if not I'll contact the guy aquapower recommends above.

Thanks for your post BTW - was hoping you'd reply having read your previous experiences!

 

[CMJ]

This was a big problem with Kawasaki jet skis with early models, There is a good machine shop in sheffield who I have used a few times and its probrably best to give Alan a call as his advise is allways good and you can send the pump to him for repair.

www.jetshed.co.uk

Tel 01142 477141

Thanks for your contact and I'll give Alan a call if Ron Hale can't help

 

[aquatom]

Yep the castings are a ba*%#$rd to split. I've always managed to split them with a hammer.

The stainless steel liner won't come out when you heat it all up as there are lugs on the outside and the casting is made around this. The last one I did was anyway. If you remove the liner you loose the power to pull up a skier and cause some cavitation.

The best bet is to fit a new section and remember to flush it with fresh water every time it is used.

 

[jfm]

I think (again rough memory) you can get the impeller out without splitting the castings sandwich and liner. I think you remove the grate over the inlet, on bottom of boat, then undo the bearing unit which is somehow bolted to the GRP hull, and the bolts you've already mentioned, then the whole impller/shaft/ castings unit comes out. I think. The shaft just slides off the flywheel - splines. Then you can pull the impeller out of the tube on a bench unless it's incredibly badly jammed, which my two haven't been.

If you want to be perfectionist then don't trim the blades, but I think you then need to buy new parts. I don't see how you can really cure the bulges in the liner, easily, and the problem will likely recur. As Tom says it must all be rinsed in freshwater after each use, though 'scuse me for preaching and I'm no angel on that score myself! I didn't suffer any cavitation or vibration or bad performance drop off (maybe I lost 3 mph) with a careful 2mm off the blade tips

Ron Hale have probably done hundreds of these so they'll know what to do. Meanwhile, I'm still firmly in the no-jets camp. Fairline have deleted (and credited me) the Williams 385 that should be on my new boat and I'm just about to order a RIB with outboard engine! (Yam or Merc 50; haven't decided which)

 

[CMJ]

Ok, update:

I didn't have much luck with RH (surprisingly as normally excellent), so spoke to Alan at Jetshed and he was brilliant – basically he advised me where I need to whack the casting so as to remove most of the pump and offered an improvement to the original design that he’s come up with (basically bore out the pump housing oversize and then fit a liner twice as thick as original with some magical Loctite stuff that’ll hinder corrosion in future – and then realign the impeller somehow) – all for £200+vat. Sounds good to me so will go with that I think assuming I can get it off the rib!

Thanks to aquapower for the recommendation

 

[jfm]

That sounds an excellent mod!

Aquatom, not Aquapower

 

[CMJ]

That sounds an excellent mod!

Aquatom, not Aquapower

I thought I was going nutttts for a min but it was aquapower (post #2), although aquatom also posted - too many aqua's I reckon - actually not enough as both very helpfull thanks

A quick fred-dwift....I too am tempted to go the outboard route and seen it debated here a few times - only thing stopping me is I don't think I'd get the buzz off an outboard jobby (please correct me if I'm wrong)...but apart from that, it's prob much better for what it's supposed to be (tender) and much lighter...the Jetrib is too heavy for the boat really and a bit of a nightmare to launch when choppy....an no good at slow speeds around rivers and marinas.....

 

[Nick_H]

I say speedfreak but I haven't had the balls yet to launch it into a 360deg spin at top speed yet as you've said you have - just working up to it

I tried this, the RIB dug in, and I split my chin open on the console. Let us know how you get on!

You're right, you don't get the same buzz from an outboard powered RIB, but they are better in all other respects.

 

[aquapower]

That sounds an excellent mod!

Aquatom, not Aquapower

Its cos we both called Tom

 

[aquapower]

Ok, update:

I didn't have much luck with RH (surprisingly as normally excellent), so spoke to Alan at Jetshed and he was brilliant – basically he advised me where I need to whack the casting so as to remove most of the pump and offered an improvement to the original design that he’s come up with (basically bore out the pump housing oversize and then fit a liner twice as thick as original with some magical Loctite stuff that’ll hinder corrosion in future – and then realign the impeller somehow) – all for £200+vat. Sounds good to me so will go with that I think assuming I can get it off the rib!

Thanks to aquapower for the recommendation

Good to know Alan can help, I had just bought a brand new seadoo rxp and stopped to help another skier who had sucked in his rope and was ok with just me but as he got on back the seadoo was a lot lower in the water and I sucked in a stone, this slightly damaged the pump and performance was down, its critical these have the correct gap round impeller to perform and seadoo's have a nylon pump insert instead of your stainless one which is meant to be the weak spot but I ended up needing new liner and rebuilt impeller After Alan recieved my pump he phoned to ask if I wanted it standard or re-pitched, normally I hate modyfying things and like to keep them original but he assured me I would notice the difference and would improve the mid range acceleration which I am pleased to say it did and so made it £200 well spent instead of wasted. Alan realy does know his stuf and is behind most of the succesfull racers.

 

[jfm]

I thought I was going nutttts for a min but it was aquapower (post #2), although aquatom also posted - too many aqua's I reckon - actually not enough as both very helpfull thanks

A quick fred-dwift....I too am tempted to go the outboard route and seen it debated here a few times - only thing stopping me is I don't think I'd get the buzz off an outboard jobby (please correct me if I'm wrong)...but apart from that, it's prob much better for what it's supposed to be (tender) and much lighter...the Jetrib is too heavy for the boat really and a bit of a nightmare to launch when choppy....an no good at slow speeds around rivers and marinas.....

Oops sorry, my mistake! Sorry Tom, both of you

Nope you wouldn't get the same buzz off an outboard, though a 3.2m lightweight with a 30hp is still pretty fast. But as Nick says in all other respects the o/b is better. Better people carrier, lighter, better at slow speed, none of these awkward breakdowns, incredibly quiet esp at idle, less fuel burn, much cheaper when new, and so on. Stick with the jet so long as you like it - I loved it and thought they were better than o/boards for about 6 years till I switched horses!

 

[Jahlive610]

would anyone know where to purchase a replacement impeller and housing for this model? I just purchased a 2006 320 DL with the 80 horsepower inboard and it locked up while awaiting launch. I can’t seem to find the correct housing anywhere and figured it would be prudent to try and get both.