To drill or not?

[OhWellcraft]

Hello to all.

1983 Wellcraft 20' cuddy with 1983 200 hp Evinrude. I am currently running a three blade alum. 15x17 prop. Runs at 5300 rpm 35-37 mph. I live in Utah and boat on a lot of mountian lakes (4600 - 5000+) feet elevation. I do alot of water sports with my boys and I still am pretty hardcore on a slalom. My question is about drilling the vent holes to help out with the hole shot a little bit. It will pull me out okay but I drag a foot and can get up behind pretty much anything. I think for beginners I would like a little more grunt out of the hole but I don't want to lose any on the top. I had a 14 1/2 x 19 and it was horrible I think alot has to do with elev. Should I drill the holes or am I stuck where I am. Can you drill an alum. prop? Any thoughts or help would be greatly appreciated.
thanks again for this great site.

 

[OhWellcraft]

Re: To drill or not?

I was hoping someone might be able to give a suggestion.. anyone just wanted some input befor I put a drill bit to a new prop. Thanks again

 

[tommays]

Re: To drill or not?

a 1/4 to 5/16 is a BIG hole on and alu prop


In general the prop is still a bit on the big size for the elevation based on the 5300 WOT

To get the best ski performance you would want to right at the MAX end of the RPM range


Tommays

 

[sharps45]

Re: To drill or not?

Hello, fellow Utahn! I too do most of my boating high up, and I couldn't get anything out of a 19 pitch. Since it was an aluminum and worth nothing for resale, I thought I'd give venting the prop a try. I did 1/4 inch holes as per instructions and it didn't make much difference. In my opinion venting may make a marginal prop better, but a prop that doesn't pull still won't after drilling. Hope that helps.

 

[OhWellcraft]

Re: To drill or not?

Thanks for the help guys.

Maybe I will try to find a 15x15 to try out I will probably lose a bit off the top end performance but it will probably clean up the bottom a bit and get me closer to my max rpm range. Does this sound like a good game plan? Sorry for all the questions but even alum. props aren't cheap so I would hate to buy one if not needed. Can the elev. affect an outboard that much it just seems like I hear of people running much bigger props on similar engines with good success. Maybe the old girl is just too tired to spin the big lumber. Thanks again for the help this site rules....

 

[tommays]

Re: To drill or not?

Anything we say "assumes" you have a healthy motor that has had the carb jeted to run at elevation


I know a seal level motor will be be crazy rich at the alt



Tommays

 

[Texasmark]

Re: To drill or not?

First thing you have to do is determine which is more important. Performance or money. Once you have determined that you can move forward.

Assuming you chose money, you are there.

Assuming you chose performance, go to a prop shop/dealer that allows you to try before you buy. Pay a little more up front, but if you are a purist, you will save money in the long run.....just bring his test props back without any dings in them to save having to have them repaired....and 6 will get you 10 you will have a shiny SS handing off your lower unit when you've finished......never saw alum beat out SS unless you like to drive over rocks.

Not being sarcastic. This is what it takes.

Mark

 

[sharps45]

Re: To drill or not?

If you find someone in Utah who will let you return a used prop without charging you 20% restocking fee let me know! I know of a couple of dealers who rent out props to try, and will take the cost of the rental off the purchase. I don't know if it's alright to list names, so pm me if you want to know. Good luck!