Prop backing off the pump threads

[MPower]

I helped a buddy modify his jetboat a while back. One of the mods was putting in a 15/20R prop. All mods were installed and everything worked great. We noticed the wear ring was in real bad shape so he ordered a new one and was going to put it in. Well the next weekend I got a call from him saying he had taken the pump back apart and put the new wear ring in with the help of a guy with a press. He also tells me that after he put everything back together and ran it for a bit the prop backed off the threads inside the pump. He said within minutes water was almost over the engine. He was close to the dock so all was well, he got it back together and all is well since then.

I've been searching the forum trying to figure out why so much water would rush in and how it is possible to mess up putting the prop back on. I wasn't there to help put it back together so I don't know WTF happened or if they left something (seal?) out. Can anybody shed some light on this? He is freaked out and thinks its going to happen again.

[meeper]

if the prop is not seated correctly it can push the driveshaft forward causing a leak at the Carbon Seal.

[MPower]

Carbon seal was what I was thinking. There are no leaks now though, so would it of been just causing a leak when the shaft was being pushed forward? No permanent damage?

[Alex13]

I had this same problem with a 15/20, Somehow my prop did not get tightened all the way and it backed off, smashing the washer on front of the drive shaft and poped the c-clip off the Carbon seal and She started to sink....Look at the treads on your prop, mine were toast..

[SearayEX12]

Is the prop backing off the shaft threads, just a question of tightening it down enough? I am about to but a prop on and haven't had an issue in the past. Everyone else here just puts some antisieze lube on the threads and then tightens the crap out it right? No body puts loctite on there allen head screw I am assuming.

[Alex13]

Is the prop backing off the shaft threads, just a question of tightening it down enough? I am about to but a prop on and haven't had an issue in the past. Everyone else here just puts some antisieze lube on the threads and then tightens the crap out it right? No body puts loctite on there allen head screw I am assuming.

My problem was the nut not being tightened correctly, now a days I tighten the screws a little tighter and never use any kind of lock tite, never had that problem again.

[jetskibill9999]

i always use a numatic wheel nut gun to remove and replace props, never had one come loose