hey guys i have a gp800 waverunner. the ski has done 300 hours and had a new engine put in some 60 hours ago. the ski only goes 70 km/h and has no 'bite' when i go to accelerate. surely these skis are ment to go faster than that !!! anyway impeller seems to be quiet tight in jetunit housing .... anyone have any ideas?? CHEERS
...it's big ski with a little motor? speedos not that accurate with age, use a gps and see how fast it goes
it almost just reves on the spot at full throttle and wont take off fast. i have used a gps and it is still only goes about 70km/H
dont listen to him.......120 horses cant beat my 85..... he has big gap between impeller and housing...... around 2 mm. get off the website.....time to pick up that compressor
Thats it. What your experencing is cavitation my friend. Its like a slipping clutch is the best way to decribe it. I dont know what the yamahas have but the seadoo's have a wear ring that you replace between the impeller and housing. The tolerances on a seadoo are fuk all. I mean feeler gauge styles. 2mm is waaayyyyy too much IMO.
yamaha blaster Manualsays: impeller clearance 0 .3mm - 0.4mm clearence (new)...and says wear limit of 0.6mm probably not too different on a GP
so basicly the jet unit is fucked and needs new impeller and rebuild of jetunit. theres thousands of dollars ahead
either replace impeller or wear ring or both. Its unlikely but you could have a broken reduction nozzle. I had this problem recently with my superjet. The plastic reduction nozzle had a split right down the top of it which caused a big loss in top speed as it would open up under load.
get hold of McIver engineering, View Rd, Rotorua. probably cost round $200 - 300 to get wearing and impella sorted they have done 3 times for me (3 different skis) and do very good job done. tho an aftermarket impella does make a big difference too
I just got my impeller back from GP Engineering in Nelson. They quoted me $100 plus GST to add about 1mm to a SOLAS superjet impeller, and it ended up being just over a hundred including GST and postage. Did a great job on it too! I would highly recommend them to do this work.
even a tiny bit of clearance like that can cause alot of power loss, replace the wear ring and the prop if it is worn...you should barely be able to see light around it if you shine a torch from other side
