The last time we took the boat out we spun a prop. The lower unit needed to be replaced so I replaced the unit and had a new hub put in the prop. I broke the lower unit in with the rebuilt prop ( full 10 hr. break in per. Stern Drive ).We broke in the prop and lower unit on Lake Greenwood – the boat was running light and we open it up ( WOT ) several times at the end of the break in period…
Took the boat out of Mount Pleasant last Sat. – got just past the rocks and it spun again. Limped back in @ 8 to 10 MPH.
Sat. we had five people on the boat – full fuel – full gear. Heat should not be a factor – new water pump. Exhuast temp…I don’t know but I’d think that wouldn’t be a problem. The prop is a 15.25 “ – 17 deg. 3 bladed stainless Power Tech.
Could the added weight have anything to do with the prop failure or do you think it was just a bad prop job…? Pain in the butt and no spare prop.
I dealt with a issue some years ago with some Bravo drives spinning the hub on Powertech props. Happened at least 3 time in 6 months. Changed to a Mecury prop and hub and the problem went away. The Customer even chewed up the prop really bad on some rocks and the hub was still okay.
I’ve come to the conclusion that the spun props are probably the result of excessive heat from the exhaust. You can smell the burnt rubber hub of this last spun prop. The second you spun after the break-in period…less than 10 hrs. of taking it easy - it then spun after only 1 hr. of hard runing right out past the rocks…
The water pump is peeing strong. I don’t have any alarms or lights going off that indicate a overheating problem but then I have to make sure the alarms and lights are working properly…
What else besides the two t-stats - a poppet valve - water hoses and water jackets are there that can cause a problem of excessive heat in the exhaust…?
This motor has a nagging problem of not wanting to run smooth after a prolonged run ( say offshore for a couple hrs ) and you cut it off. When you try to restart right away - it wants to run rough - keeps cutting off…etc. It will finally straighten out but it seems to have to cool down some… It could be the same problem of overheating that I believe is causing the props to spin…
Not arguing, but ‘doubt’ it is heat related. Spun hubs do heat up on their own and can give the same ‘burnt smell’.
Sorry you’re having so much trouble, and your suggestion is also possible…
quote: Not arguing, but 'doubt' it is heat related. Spun hubs do heat up on their own and can give the same 'burnt smell'.
+1
You’re sending yourself on a wild goose chase if you go down the heat related path. I’ll be more direct with my advise this time; The hub for the prop you are running are a POS.
quote:I'll be more direct with my advise this time; The hub for the prop you are running are a POS.
The hub is a POS … or the Power Tech prop is…? Both…? I didn’t know there was that much differences in hubs.
I just took it to a prop shop for repair, I don’t have a clue what name brand of hub they installed the first time…( it’s at the same shop right now getting re-hubed for the second time ). I guess I’ll end up with the same type hub the second time around…no charge for the second hub. Maybe time for a new prop setup… I’ll see what this new hub does first…
quote: Not arguing, but 'doubt' it is heat related. Spun hubs do heat up on their own and can give the same 'burnt smell'.
Good point… It could have been just a bad hub the first time but what’s the chances of the next one spinning the second time around…?
The props are okay, it is just the hub that they use on some models. It seems that they change hub design every so often. I don’t know whether what they have now is good or not. I know they also started making knock off Mercury Flotorq hubs.
The problem is that you are kind of limited by the prop to what hub you use. I’m guessing that you have some sort of rubber/brass pressed into hub. Contrary to a Merc Flotorq which is Delrin plastic and slips in with some persuasion with a block of wood and a hammer.
If it happens again it is probably best that you do look for another prop that uses a better hub (hint: Mercury Mirage Plus for your application). There are some good deals on props out there if you look around. You could probably hock what you have as well to defray the cost.