Will PVS have effect on 60 hp engine?

[Mesteren]

I have a 16 foot speedboat with a 60 hp Mariner four stroke engine from 2001. The hole shot is good with two or three people on board. The problem is, however, that when pulling a water-skier out of the water the boat seems to lack a bit of power and doesn’t plane of as easily. The skier will get up, but I just wish it happened a little quicker. The propeller is a Black Max alloy with 10 2/3 or 10 1/2 inch diameter and 13 inch pitch, which gives at top speed of 32-33 knots at WOT at 5950 rpm (recommended 5500-6000 rpm).<br /><br />I have read about the performance vent system (PVS) and I have thought about drilling holes in the propeller to give a better acceleration while pulling a skier. I don’t know if it is a good idea because some people say that the PVS only has effect on larger engines. What is your experience/opinion on this? Should I drill the holes or should I try with at propeller with more than three blades, designed to give a better hole shot?<br /><br />Thank you

 

[Moody Blue]

Re: Will PVS have effect on 60 hp engine?

Are you expecting too much from your 60HP motor ? No expert for sure but a 60 on a 16ft sounds marginal for skiing to me. What is the max HP rating for the boat ? How many on-board when trying to pullup a skier ?

 

[Mesteren]

Re: Will PVS have effect on 60 hp engine?

The boat has a 90 hp maximum rating and there are usually two people in the boat when waterskiing. I am aware that with only two thirds of the maximum engine rating I shouldn’t expect superior performance (but I might expect too much though). The package performs just acceptable as it is now, and I was wondering if I could get a better hole shot by drilling ventilation holes in my propeller.

 

[ziemann]

Re: Will PVS have effect on 60 hp engine?

Do a search on these boards- there are tons of threads regarding this issue. IF you had a large 2 stroke, you would likely see a benefit. But since this is a 60 hp 4 stroke, you will not see the benefit that you are expecting.

 

[Moody Blue]

Re: Will PVS have effect on 60 hp engine?

I didn't notice the 4-stroke in the original post. Like z-man pointed out there have been previous posts about just this issue. Search for "venting" or "modifying prop" or "drilled prop".<br /><br />I have a 40hp 2-stroke on a 14ft sport boat. Good hole shot and fast (for the size boat) but decided to try venting the prop as an experiment. Drilled up to 3/16" diam with no affect, positive or negative. Didn't want to go bigger for fear of screwing up the prop.

 

[tee-boy]

Re: Will PVS have effect on 60 hp engine?

Mester, I vented that same prop on a 60 4strk Merc about 6 months ago. I kept drilling larger and larger and found no effect. I quit at 3/16. 4 strokes don't benefit like the 2 strokes.

 

[Navigator]

Re: Will PVS have effect on 60 hp engine?

Mesteren,<br /><br />60 hp is marginal for pulling a skiier especially with 2 people on board. You're simply lacking the horsepower to give great hole shot.<br />That said, you could always drop an inch down in prop pitch and go up to a 4 bladed prop. You'll loose top end, but you'll gain hole shot. The extra blade will give you a little bit more bite. You can also get a performance boost by switching to a stainless prop. Stainless props are much stronger and have thinner blades so they are more efficient. Plus, the blades wont flex when put under a heavy load like other prop materials do.<br /> <br />It will help, but dont get your hopes up too much <br /><br />Nav

 

[Mesteren]

Re: Will PVS have effect on 60 hp engine?

Thank you all for your replies. I have now dropped the idea about drilling holes in my prop, thanks to your advices.