Hit rock, need to fix prop...

[Mark42]

OOPS! I wasn't paying attention and got in shallow water and hit a rock at about half throttle. The prop is an aluminum Turning Point Hustler model. There are two flat spots on the leading edge of two blades near the tip about 1" long each. Does not look like much damage, but it is enough that I noticed a mild vibration and when went WOT, the vibration is worse and the top end is cut about 1-2 MPH. The blades do not look bent, its just the leading edge that took a wack.<br /><br />So I need to know the way to go about balancing the prop. I can easily file the impacted (sort of flattened) edges back to a sharp edge, but what about balance? Where do I remove weight from on the blade that was not impacted? <br /><br />I did some searches on this topic but did not find anything on balancing a prop. <br /><br />Thanks,<br />Mark

 

[petrolhead]

Re: Hit rock, need to fix prop...

I rebuilt a couple of fairly large chunks missing from the leading edges of my prop, did it with Technoweld, after cleaning up with a file the prop was in near perfect balance. I did the final balancing by spraying more primer on the lightest blade when I repainted it.

 

[ob]

Re: Hit rock, need to fix prop...

I recommend inspecting the propshaft to insure that it didn't suffer a bend during the rock episode.With the prop removed ,perform or have performed a runout with a dial indicator.A bend in excess of .010 will translate to excessive rotational vibration with prop installed.Good luck and hopefully damage is limited to the prop itself.

 

[Mark42]

Re: Hit rock, need to fix prop...

Thanks Petrolhead,<br /><br />How did you go about checking the balance? Can I use a static tire balancer or something similar?

 

[BF]

Re: Hit rock, need to fix prop...

I'd recommend taking it to a heli-arc (aluminum) welder who routinely does props. They'll straighten/build up with fresh aluminum, re-grind and re-balance it. And it's usually cheap! I've had several badly damaged props (much worse than yours) put good as new for $35-50. Depending on the guy, he might even be able to tweak the pitch up or down an inch if you request it, or add some cup.<br /><br />My guy quotes based on how bad it is since that determines how long it take him to repair. He's a bit cheaper than other guys around here.<br /><br />Also I would not run the boat with this prop, unless I needed to limp home at low speed. If the vibration is bad enough to feel, it could destroy your lower unit in a hurry! A friend killed his I/O outdrive in that exact way (after 15-20 minutes of vibration).<br /><br />Good luck!

 

[petrolhead]

Re: Hit rock, need to fix prop...

I used a prop balancer to check mine, it's one that I made for balancing model aeroplane props, it works just as well with outboard props!

 

[Solittle]

Re: Hit rock, need to fix prop...

Mark - The prop should not be out of balence unless you lost some metal off of the prop. The vibration is most likely caused by the bending of the two blades - each blade biting the water differently.<br /><br />I have "unbent" props with a hammer, a block of wood and a bag of sand. Use the sand as a backing and put the wood on the blade and hit with a hammer. <br /><br />If you decide to have it done (which is really what you should do) take it (or send it) to a prop shop. They will refirbish it like new. I would not give it to a welder unless he had extensive experience with marine props.

 

[Mark42]

Re: Hit rock, need to fix prop...

SoLittle,<br /><br />I think you are right. The shaft checks out true, and the end of two blades no longer have a nice sharp edge. When looking down the blade edge, one has a T shape where the edge has flattened, the other is half a T, looks like it is missing a little material.<br /><br />This prop is a little more high tech than the last OMC prop I had. That one I picked up used and filed the bad spots off, hammered the wavy spots out and it ran fine until I took off with the prop half burried in pebbles (Ooops!).<br /><br />Anyway, the Turning Point is cupped and has more shaped surfaces, but I will try cleaning it up as you suggest. Think I will put it off till next year, as I am getting ready to fog it an store it for the winter. <br /><br />Thanks,<br />Mark

 

[MarkHPCA]

Re: Hit rock, need to fix prop...

Mark42.<br />I thought the idea of the Turning Point props is that the blade part, being seperate from the hub, is so cheap ($35) it's not worth fixing, just replace with a new one.

 

[Scaaty]

Re: Hit rock, need to fix prop...

Is there no "prop fixit" service at your area? We have Tacoma Prop here in WA thats stops at all the boat shops up and down the "Sound", and picks up the "dingers" on Monday and usually has the props back for pick up by Friday so people can do it all over again. They do a great job, cheap, and don't charge if they can't fix it.

 

[G DANE]

Re: Hit rock, need to fix prop...

You guys are so luckey. I only know of one propshop here in Denmark, and they charge 1/2 of the retail price of a new prop for any repairs, whatever it is, a dinged blade or even rehubbing. Fixed price, unwilling to negociate. Prop will be returned painted and balanced though. But cheap it surely isnt, you can often shop around and get a new at an offer cheaper, I did so.

 

[Mark42]

Re: Hit rock, need to fix prop...

MarkHPCA,<br /><br />My prop sells for $50, and I do have a spare. Just thought the damage to this one is so minor I could fix it myself. Doesn't pay to bring it somewhere.<br /><br />May try Marine Tex epoxy or the Technoweld stuff. Will worry about it in the spring.