PVS Vents and Jack Plate issues

This topic has 8 replies, 3 voices, and was last updated 20 years, 7 months ago by revtro.

Viewing 9 posts - 1 through 9 (of 9 total)

Author

Posts
September 20, 2005 at 7:22 pm #340251

revtro
Participant

Hi,I have an 03 P3 with 200 EFI. My hole shot has always been quite slow, so I decided to remove two of the vent plugs. Things improved a bit, but sometimes going with a strong current, I cant get on plane. So I guess I need to experiment with the vent plugs more, but cant find a place that carries them. Thats the first issue.The second is related. I went out with a friend of mine yesterday on his boat and experienced a 1-2 second hole shot with a bigger boat. This dramatically showed me that things are not right with my setup. My initial thought is that my jackplate needs adjustment. I need some help with that as I know nothing about proper jackplate setup. Im not sure if I need to start by lowering it or raising it. My top end speed is pretty good, so I dont want to mess with that too much, but I need to make dramatic improvements with my hole shot. 6-8 seconds is a far cry from the 1-2 seconds I experienced yesterday. How can I get closer to that? I know I may not be able to get all the way there, but Im convinced it can be much better.Thanks in advance for any help anyone can offer.

September 20, 2005 at 9:21 pm #340267

PhilAddison
Participant

Probably the only way to improve your hole shot is to change props. Other ways to improve are to reduce the load in the boat. Lowering the jack plate probably wont do it, but what do you have to lose? Lowering the jack plate will certainly cut out some of the ventilation/cavitation, but it will affect your top end speed. It may increase it, but it also may have a negative effect. More info is needed such as top end speed rpms, top end gps speed, prop size/type, etc. to further help. Best advice I can give is to experiment with all and see what you come up with. Good luck!Phil

September 20, 2005 at 11:48 pm #340277

revtro
Participant

Ill try to get it in the water in the next day or two and get the data you are recommending to get. Hopefully thatll help lead to an answer. Thanks!

October 11, 2005 at 9:13 pm #340290

revtro
Participant

Heres what I have. 25p Trophy Plus. 200 MercEFI During the hole shot it topped out at 4220rpm. At 55mph it runs about 5200rpm and at 60 it runs about 5500rpm. The fastest Ive had the boat is 69mph on the GPS. I couldnt get it up to that speed the other day because of lake conditions, but with the numbers I have here, Id imagine topping out around 6,000rpm.So heres what I did that day:I changed the vent plugs from the large ones (which came on it from the dealer) to medium ones and guess what? It jumped right up on plane! In fact, it made such a dramatic difference, that Im wondering if one of those plastic rings that goes at the bottom of the prop between it and the shaft housing to prevent venting would help even more. I dont know what those are called or where to even look for one. A friend of mine had it on his Ranger. Any idea what thats called?

October 12, 2005 at 4:33 pm #340305

PhilAddison
Participant

I call them cavitation or blow out rings, but the real terminology is seal ring. The Mercury part # is 878421 and any Mercury dealer should be able to order you one.

October 12, 2005 at 5:32 pm #340317

revtro
Participant

Great. Ill order one and give it a try. So for a 25p TrophyPlus on a Pantera 3 w/200 EFI, are those good numbers?

October 12, 2005 at 11:04 pm #340344

PhilAddison
Participant

Decent numbers. You need to be exact when talking about top end speed and whether or not the numbers can be improved upon. Plus, every individual has their own wants and needs. Some prefer holeshot and acceleration where others prefer top end speed. Get a few good runs in and post your numbers (gps speed/fuel, livewells, 1 or 2 people / max rpms). By the way, weight has a tremendous affect on speed and hole shot. It can affect your top end mph by as much as 3-5 mph depending on how loaded and your holeshot by as much as several seconds as well. Good luck w/ your setup.Phil

November 7, 2005 at 5:52 pm #340361

ezbassin
Participant

I would have thought that going from the large vent holes to the smaller ones would have a negative effect on what you are trying to do. When you vent more you get more prop slip, therefore you can trun more rpm at take off and get up faster, but hey if you found what works for your set up that is great. Makes you feel good when a plan comes together.

November 7, 2005 at 8:29 pm #340378

revtro
Participant

Yeah, all I can figure is that I was getting too much slip and therefore not enough tork to get it up on plane. Ive heard that can happen. Either way, when I went to smaller plugs, it got right on plane for me. I was surprised. Ill take it.
Author

Posts

Viewing 9 posts - 1 through 9 (of 9 total)

You must be logged in to reply to this topic. Login Register