i drilled holes in my prop, guess what happened?

[steelespike]

Re: i drilled holes in my prop, guess what happened?

I have to ask this.Is there a down side?What happens with a max load, tight manuvers,all out emergency reverse?etc.There must be a down side or manufacturers would do it to all their props<br />wouldnt they?

 

[phatmanmike]

Re: i drilled holes in my prop, guess what happened?

sorry cheif, no down side. unless you make the holes too big.<br /><br />i start off at 1/8" and try that, then go up 1/16" at a time, one hole at a time.<br /><br />it allows the exhaust gasses to be pushed out of the hole in addition to the "through prop" area. at mid speed and high speed it does nothing.<br /><br />tight turning on my boat , it would blow out , but thats cause i made the holes too big. <br /><br />just start small, youll be amazed

 

[LubeDude]

Re: i drilled holes in my prop, guess what happened?

I bought a High five prop off Ebay, It has the biggest holes in it I have ever seen. I can stick my index finger in them up to the first knuckle. (I have smallish hands for a man though). They are factory, as you can tell they were cast that way. Instant hole shot. The prop works fine as is, and has no effect on top end and dosnt blow out in tight turms.

 

[Dave Abrahamson]

Re: i drilled holes in my prop, guess what happened?

"have it prepped for the Mercury PVS plugs."<br />Probably a dumb question, but what are PVS plugs?<br />Propellor Ventilation System? Merc?? I have a Johnny. Does it matter? Sorry if I'm asking so many questions, but with MY budget, I'd hate to mess up a perfectly good prop. especially a SS one. Thanks all and Happy Christmas and a merry new year.<br /><br />Dave

 

[phatmanmike]

Re: i drilled holes in my prop, guess what happened?

dave , take it to a prop shop and just tell them you want it prepped for the pvs holes, they know what you mean. i couldnt tell ya what it stands for..<br /><br />or just drill ya some small 1/8 inch holes...<br /><br />or heck, email me, ive done it before, and im just down the road in largo/clearwater area, i could show ya what i did at least.....

 

[bb_ed]

Re: i drilled holes in my prop, guess what happened?

<snip> i couldnt tell ya what it stands for..

Performance Vent System<br /> <br />Mercury Propeller Terms <br /><br />This is a good propeller primer. Use the navigation on the left side of the page.<br /><br />Ed.

 

[swist]

Re: i drilled holes in my prop, guess what happened?

So I still don't see why all props don't come from the factory this way if there is no downside. Sorry I'm always suspicious of stuff like this.

 

[bb_ed]

Re: i drilled holes in my prop, guess what happened?

It doesn't always work. There have been a lot of testimonials on these bulletin boards but few people have written about their negative expereinces. <br /><br />Ed

 

[sangerwaker]

Re: i drilled holes in my prop, guess what happened?

I would guess all props don't come vented because it would add cost to manufacture them that way. Look at most high end performance stainless props. Most come with vent holes, or the Merc ones come with the PVS plugs so you can adjust or tune the ventilation.

 

[shep70057]

Re: i drilled holes in my prop, guess what happened?

Props don't come vented because not all boats need them. Not to mention if the holes aren't the right size the prop is then useless. My 4 blade from Power Tech came with ports and it did make a difference.

 

[phatmanmike]

Re: i drilled holes in my prop, guess what happened?

It doesn't always work. There have been a lot of testimonials on these bulletin boards but few people have written about their negative expereinces

id like to see somebody who did it correctly and have a negative experience.<br /><br />mathematicaly and mechanically, if you have a through hub exhaust on an outboard, this will make improvements

 

[badbass]

Re: i drilled holes in my prop, guess what happened?

Worked for me<br /><br />Thanks

 

[walleyehed]

Re: i drilled holes in my prop, guess what happened?

This process works best on efficient designs incorporating good cup (bite). On an uncupped prop, or one with neutral rake, it may do nothing but cavitate...it may not plane at all.<br />Venting the prop is the best way to keep top end AND the best hole-shot at the same time-less trade-off you might say.

 

[Mark42]

Re: i drilled holes in my prop, guess what happened?

My emergency backup prop is an OMC that someone drilled the vent holes in. They drilled them too big causing over-reving at cruising speed, not even wot. To make matters worse, the prop is 13 pitch and the boat performs best with a 15 pitch. <br /><br />To fill in these holes I was just going to file the edges clean and rough then fill them with Marine Tex epoxy. Masking tape on the inside should make a resonable form to hold the epoxy in place while it hardens. Think it will hold?

 

[walleyehed]

Re: i drilled holes in my prop, guess what happened?

Mark42, that marine-tex is some tuff-stuff.<br />I think if you just hit the outside of the hole with a countr-sink, or chamfer the holes slightly, you'd have more adhesive surface area, and I think it would stick just fine.

 

[Dave Abrahamson]

Re: i drilled holes in my prop, guess what happened?

Well, I did it. Drilled the holes in the exact spot shown on the OMC diagram. Started with the smallest holes,(7/32). Took the boat out for a test run.....I thought I spun the hub!!!<br />As soon as you give her some throttle, the prop ventilated so badly I had to come off the gas for fear of over-revving the engine. At least that's what I think was happening. (1983 Johnny 90 with a 17p SS prop). SOOOO....JB weld to the rescue. I didn't have any Marine Tex so I used what was on hand. Went back out and the problem dissapeared. Oh well, can't say I didn't try. I guess it doesn't work for all applications.<br /><br />Dave

 

[ddaigle]

Re: i drilled holes in my prop, guess what happened?

My rapture prop has vent holes but it also came with plastic plugs. So as Dave says it depends on the boat. I run a jackplate at very high levels so I dont want or need any cavitation.

 

[phatmanmike]

Re: i drilled holes in my prop, guess what happened?

dave, this truly shouldve worked for your boat and motor combo. maybe something was amiss. <br /><br />i know i did it exactly in the center between each blade, about 1/2 inch from the edge where it meets the lower unit, i used 1/8" holes and presto, instant flight! mine worked perfectly on a 17 foot center console with 115 merc with 21p prop.<br /><br />my buddy has a 17' center console with 70hp evinrude tripple and stainless steep 17p prop, we did same thing to his and works excellent. talk about throwback!! wooo hoooo

 

[Dave Abrahamson]

Re: i drilled holes in my prop, guess what happened?

I drilled mine at 5/8 in from the lip at the front of the prop(facing the bow) and 5/8 from the edge of the blade....like OMC said <br />Mike, you drilled centered between the blades? Hey, it worked for you but, how did you come up with that location? What made you not go by the OMC diagram? My holes were not even close to centered between the blabes. They were basically right behind the blade. <br /><br />

<br /><br />Confused Dave

 

[walleyehed]

Re: i drilled holes in my prop, guess what happened?

Dave, ALWAYS start small...I've mentioned this on other posts and it depends greatly on prop design as to how large you can go.<br />I would find rare occasion to ever go bigger than 3/16, with 1/8" being the starting point and testing from there.