stock square cavitating on takeoff.

[Dubs chops]

ok guys i took the ol stock squares i bought out saturday. i noticed that one of them cavitates i beleive on takeoff, it revs plent fast but isnt hooking up it takes about 5 seconds to get on plane? i beleive they are both stock. anyideas why one is doing this and the other is not?

 

[Mouthfulloflake]

post some pics from underneath looking in.

look for damage on the leading edges of the impeller and pump veins.

you might be lucky and the pump is simply not sealed well, there is a rubber ring at the front, and you have to hold your mouth just right to get the pump installed and sealed off well.

 

[augustaf]

ok guys i took the ol stock squares i bought out saturday. i noticed that one of them cavitates i beleive on takeoff, it revs plent fast but isnt hooking up it takes about 5 seconds to get on plane? i beleive they are both stock. anyideas why one is doing this and the other is not?

Possibly 'cause one has a worn impeller and the other one does not. Jet pump impellers require a fit of no more than about .015" in the housing. If you can fit a .020" feeler gage easily between imp blade and housing you will get cavitation due to worn impeller. If it's a stock (thick aluminum painted green)impeller, it will wear out quickly.

 

[Rickster]

Check the seals on the intermediate housing, you may be sucking some air into the pump.

opworm:

 

[Dubs chops]

ski's arenty at my house but i will look tomorrow or as soon as i get them back home, thanks for the help.