Spun Prop or Bad Coupler?

[testdrctr]

While taking my 1986 SeaRay Seville (4.3L I/O) for a spin I pushed the RPM to about 4000. At that time, the boat slowed down (obviously not being propelled) and the RPM began to run away. Immediately pulled it back. As the RPM wound down, the boat felt like it "caught" and began to run what appeared to be normal.<br /><br />I began to cruise around 3000-3500 with no problem, then got the same problem around 4000 RPM with the same outcome after I powered back. Also, out of the hole shot, the RPM spun away with no traction. <br /><br />So do I have just a bad prop or dare I say a bad coupler. Going to put a spare on and try it again probably next week, but I'm curious as to what you folks think of how this will turn out. Thanks in advance

 

[ODDD1]

Re: Spun Prop or Bad Coupler?

Mike, are you sure that prop isnt just cavitating? how bent is it? something hanging on the front of the drive? usually when rubber hubs and couplers fail, they go downhill rapidly, to where you are idling off the lake, if at all...

 

[fone_man]

Re: Spun Prop or Bad Coupler?

testdrctr:<br /><br />From my experiences you have a spun prop... that why the "spare" is always in truck, so it doesn't spoil the day on the water.<br /><br />Carry it to prop shop to be repaired & go again.......<br /><br />

 

[testdrctr]

Re: Spun Prop or Bad Coupler?

Thanks for the response guys. I'm sure the boat is not cavitating. The prop is not bent in any way...but it is getting up on years. <br /><br />Guess I'll just have to put it back in with a good screw to be sure. If not the prop, I'll be back on with questions on how to remove an engine to change a coupler!!<br /><br />Mike

 

[fone_man]

Re: Spun Prop or Bad Coupler?

Mike:<br /><br />Just sold my boat 86 Fourwinns w/ MerCruiser... are you the same. Guy that bought it tried to save money & cut me a couple hundred dollars & I said sold but I kept my spares. Like brand new, fresh from prop shop getting nicks taken out... so they have been checked out... I will take $180.00 for both 17 pitch & 19 pitch MerCruiser. Let me know....<br /><br />

 

[testdrctr]

Re: Spun Prop or Bad Coupler?

hey fone_man,<br /><br />Thanks for the prop offer. Problem is, I dont want to blow a load on props when my problem might be the coupler. If it is the coupler, then the boat will be sold or donated. I don't have the time or desire to put that much cash into a 15 year old boat. I'm looking for a prop on the "cheap" just to test the thing out. If it checks ok, then I'll invest in some good screws.<br /><br />BTW: I read somewhere that repaired props (hubs) were more likely to have repeat problems. Any truth to that? <br /><br />Mike

 

[Bob_VT]

Re: Spun Prop or Bad Coupler?

Mark the prop and inner hub with a marker (waterproof) or scribe a line in with a nail or use nail polish. Mark across the inside of the hub, the rubber bushing, and the outter hub. Give the boat a spin and after it "slips" remove and check your marks. This will tell you if it is the hub or not. I doubt it is the coupler.<br /><br />Bob

 

[port jeff boater]

Re: Spun Prop or Bad Coupler?

hey fone man.. i have the exact same boat 86 four winns 195 horizon cuddy. i hope you can help me out. im having some throttle problems, when i open her up at full throttle after about 4 or so minutes i get a rattling in the engine and then the rpms drop and the boat slows down. when i pull back on the throttle and wait a few seconds i can open her up again and it runs fine for another 4 or so minutes then the same rattling noise and loss of rpms and power any suggestins why,, any and all help wanted please,, thanks a lot,, i might also be interested in your props if i can fix this problem,, thanks,,,,also, when im at 3/4 throttle she runs fine with no rattling or loss of power,,

 

[testdrctr]

Re: Spun Prop or Bad Coupler?

took my prop to a prop specialty shop. he said he highly doubts it is my prop's hub that's bad...and he doubts it's my coupler. my diffuser ring came off the prop (yea, i knew that...shame) and he says the exhaust gases can cause serious cavitation at high rpm....especially out of the hole. my symptoms to a tee. so i bought a new prop, and if that works, i'll have him press a new ring on the old one for a spare. we'll see what happens next weekend.

 

[flashback]

Re: Spun Prop or Bad Coupler?

are you overheating? if you are then the coupler is probably spun......... ask Trent if it is a merc.

 

[testdrctr]

Re: Spun Prop or Bad Coupler?

didn't notice any overheating...but i didn't let it run but a split sec when the rpm began to run away. i performed the same "test" a few times just to be sure i knew what i was looking at and still no overheating.<br /><br />guess it could still be the coupler, the most of the evidance says no.....of course most of the evidance said OJ did it!

 

[Trent]

Re: Spun Prop or Bad Coupler?

Most of the time..YOu can look on the back of the engine for "rubber dust" If so its the coupler.