I had the exact same problem as you do last year. I took the whole thing apart. Tuns out that the wire tie that clamps one of the internal hoses broke and the hose came off, thus spraying water inside the unit instead of through the venturis. However it is somewhat hidden, you not only have to take the blue body off but also the "sub" frame attached by 4 screws. Then you can see all the hoses. Since I had apart, I replaced alot of stuff, bearings, wheels, gears etc.
I fired it up and good as new.