Prop wash?

[jsaylor]

I tried switching from my high 5 17p to my 4 blade stainless 19, while getting on plane or shortly after my rpm's would rise however not pick up speed, it seemed like it was slipping. Is this called prop wash? how do you eliminate. I;m not new to boating and have never experienced this

 

[Triton II]

Re: Prop wash?

I suspect your prop is ventilating i.e sucking air instead of driving water. Try trimming the motor down more and let us know if that helps the prop bite. If not, you may have a spun hub.

TII

 

[marcoalza]

Re: Prop wash?

Hi jsaylor, Try this thread. Might help

http://forums.iboats.com/showthread.php?t=450498&highlight=prop+wash+question

 

[Home Cookin']

Re: Prop wash?

when I was trying out props they suggested lowering the motor a hole when I increased the diameter.
I also recall one of the props acting like you described, so I did not buy it.
Then the one I settled on, new except the trial run, spun itself; the dealer fixed it (free).

 

[craze1cars]

Re: Prop wash?

Far more information is needed for anyone to provide a meaningful answer...

Type of boat and motor in particular. Bass boat? I/O? Outboard fishing rig? Inboard? V-drive?

And photos of your current setup are worth 1000 words.

 

[Mi duckdown]

Re: Prop wash?

+1 Craze. It is meaningless without more info.

 

[jsaylor]

Re: Prop wash?

Sorry for the lack of info, the boat is a 1980 Tahiti Daycruiser 25ft with a 454, the trim was down all the way.
Thanks for all your help

 

[jsaylor]

Re: Prop wash?

Can I some how bench test to verify a spun hub? also the outdrive is a Alfa1

 

[Robbabob]

Re: Prop wash?

Can I some how bench test to verify a spun hub? also the outdrive is a Alfa1

To test for a spun hub, you must take the boat out onto the water. Before hand, draw a line with paint along the prop nut and the hub; able to see if when the occurrence takes place if the hub is spinning or the prop is cavitating. After you feel it, raise the drive and see if the paint lines still match up.

 

[jsaylor]

Re: Prop wash?

Can I repair myself?

 

[Triton II]

Re: Prop wash?

Can I repair myself?

Most props have a pressed in hub insert between the shaft housing and the outer body of the hub. Best left to a prop shop to fix unless you have the tools to press out the old insert and press in the new one. Shouldn't be an expensive job...

TII

 

[88wellcraft]

Re: Prop wash?

Is this called prop wash?

That's the stuff you clean the prop with right?

sorry...just reflecting on my helicopter mechanic days:redface:

 

[craze1cars]

Re: Prop wash?

Does your new prop have ventillation holes, and your old one maybe did not? It shouldn't be as extreme as you are experiencing however...

Have you checked for a rip in your exhaust bellows?

Can you put the other prop back on for a run, to confirm it is indeed the prop causing the problem, and not something else?

If the hub on the prop itself is not spun, it is equally possible your engine coupler is failing...gives similar symptoms.

Best way to test for spun prop hub before another test run: Make scrach marks or paint marks on hub and prop and make sure they haven't separated after your test drive.