i think i spun my prop... help
 

guys i think i spun my prop because the boat runs a little different now... doesnt get up on plane as fast as usual but rpms are screaming. so got home and looked at the prop and its loose on the shaft. the nut is still on and so is the safety pin. any body know of a place in miami to fix this ? or can i do it myself? thanks
-evan

Re: i think i spun my prop... help
 

Any prop shop or the prop guys do pick and drop off at all the marinas, not expensive and common.

Re: i think i spun my prop... help
 

yup....you spun the rubber hub, about $50 to have re hubbed

Re: i think i spun my prop... help
 

im getting my old one rehubbed. it was 15x17. went ahead and bought a new prop also. went to a 14.5x19. hopefully get more than 35mph at 5k like i am now.

Re: i think i spun my prop... help
 

http://www.gpcprop.com/

Re: i think i spun my prop... help
 

:D Spun props usually don't allow you to even get on plane, but a loose prop that allows exhaust gas to ventilate will do that. Try tightening your prop first. If you're lucky, that will be it.

Of course the mystery is still how it would have loosened in the first place since the castle nut and cotter pin are still there.

Re: i think i spun my prop... help
 

the nut and cotter pin were still there. since i put on the new prop and hub the problem is a thing of the past. boat is alot faster with this new prop i put on. i got 39 mph at wot 4800. 1985 evinrude 150.
-evan

Re: i think i spun my prop... help
 

Best RPM for that motor is 5200 to 5400, @ 4800 it will have a slow hole shot and you won't lose top end may even get more going down 2" in pitch.

Re: i think i spun my prop... help
 

so if my current prop is 14.5 x 19 u say i should go to a 14.5 x 17? i used to have a 15 x 17 and i only got 5000 rpm at 35mph.
-evan

Re: i think i spun my prop... help
 

All is not a matter of pitch and diameter. Rake, cup, and shape of the blades all make a big difference.

Re: i think i spun my prop... help
 

True but it still needs RPM, the other factors are more bow lift vs stern lift and stuff like that. I thought you were getting the 17 fixed??, the motor lugs like having your car in too high a gear and that hurts performance and shortens engine life.

Re: i think i spun my prop... help
 

i went today and bought a brand new 15 x 17 like my original. i think the new prop alone helped. cruise is still the same at 28 mph @ 4K. and top end is now 38 mph @ 55K. so i guess ill be sticking to my original prop.
egg, so even cruising at 4K with that 14.5 x 19 putting a strain on the engine? out of the hole performance cant be matched tho.
-evan

Re: i think i spun my prop... help
 

Ideallly you want your motor to rev in the high end of it's range. The prop that only turned 4800 is like driving on the highway in second gear. You'll shorten the motors life and burn more gas at a given speed.

Re: i think i spun my prop... help
 

the 15 x 17 seems to be the best prop. 5500rpm gives 38.1 mph with 3 people in the boat. and out of the hole performnance is good if motor is trimmed properly. guess i have to put my hydrfoil back on the cavitation plate..
-evan

Re: i think i spun my prop... help
 

Sounds perfect, 28@ 4K isn't bad at all, my 20 w/200 is around there at 3500/3600- you mentioned the cav plate, have you checked the engine height? the cav plate should be approx 1" above the bottom of the hull. This can make a boat ride and handle much better if its correct.

Re: i think i spun my prop... help
 

well i think why it was cavitating the other day was because i had the engine trimmed too high.. when i tested that new prop the day before it jumped right onto plane. so this weekend i will try it again with the motor trimmed down.. i have one of those fins that mounts on the plate that i used to have on there. what do u get on ur 20 at WOT with the 200? and what 200 is it?
-evan
-evan

Re: i think i spun my prop... help
 

Its a 94 Merc XRi and best I've seen was 49 with just me, I just bought it and a better prop is not at the top, but it does have a T Top too. Yes when getting out quick have the motor trimmmed as far in as possible then bring it up some, unless you have alot of cup you can't trim too high before losing bite.