Hello all, newbie here, have a problem with my cen greythunder....every time I use it, it fills up with water. But can't see how the water is getting in, no visible holes at all. I've left it floating in the bath overnight but no water seemed to get in - only seems to fill with water if actually being used. This is puzzling me, please help!

ok 2 solutions !
put the boat in a tub of water and drop colourd dye into the water like red it works good then plung the boat in as far as u can with your hands and then see were the water comes in from the dye marks !

OR
you could take out all the stuff in the hull and fill the hull up with water and set it on paper then lift it up after like 20 seconds and see where the water mak is then follow the water strean to find the crack or whole !

Jeremy2006,
If there are no hole in the hull then I'd start looking at the things going through the hull. As in the stuffing box/drivehaft and rudder tubes, etc. If one of those is the problem then run the boat in the test tank (bathtub) to be sure. Be prepared for you-wouldn't-believe-how-much-trouble from 'she who is to be obeyed'...
- 'Doc

i'm not particular with greythunder but maybe this will help u, i drilled a hole in the shaft tubing in my nitro hammer and it helps a lot, before the water will suck up everytime i run but not this time..i also used it for oiling the shaft coz it's hard to reach inside with hammer set-up.

Well, seeing how you're in the nitro boat forum I'm safe in assuming that's the version that you have. I'm suspecting that is it coming in while the boat is on the water so I'd be looking at the head or the water lines for leaks or cracks.

Thanks guys, no there are definitely no cracks.....and I have left it in the bath overnight but no water gets in. It's only when it is actually running that it fills up

Check the head bolts for tightness.
As you can see in the shot below, I pulled mine off and rotated it 90 degrees as I don't like the idea of having the water inlet over the top of the carb.
It still has to be something inside the boat that is allowing the water in as to why I'm thinking the head or coolant lines if it's only getting water in while running.

could the flexshaft tbe acting like a ice ddrill or auger when it spins it moves water up and in to your boat? dont no if its possible its just a thought

It's got a straight shaft in it. Unless the bottom bushing is bad it really shouldn't leak at all or at least pull any water up into the hull. There is a hole at the top of the propshaft tube for oiling so he should have seen water there or it coming out after taking it out of the tub if it was bad.