vent plugs question - Better hole shot ???

[Openfacereel]

Hey guys, My out of the hole performance is not good in my opinion. Can someone clarify my thinking on this? To have better out of the hole performance I would want to use plugs ?? or maybe smaller hole plugs? Is my thinking correct or do I have it backwards?
Prop is a 25P Tempest

[wmitch2]

What do you have in now ? I'd start with open holes, then work your way down. Mine blew out at open, best hole shot is with 2 plugged or 4 medium.

[XingEyeballs]

It depends on what you’re rpms are on hole-shot. If it’s not get up to 3500-4000 as it’s coming out, more venting(holes open) will help it spool up. If it’s blowing out the prop on hole shot, less venting (holes plugged) will allow it to grip more.
That’s assuming it’s a two stroke outboard and close to the right prop for the boat/load and of course a healthy motor.

[Openfacereel]

Ok Thanks guys, That's pretty much what I was thinking, just needed some clarification. and yes its a Merc 2 stroke 200HP Based on the setups page the 25P temptest is what I should be running. I will check a few of the suggestions you made and go from there. Thank you for the advice on the 3500-4000 RPM'S while getting on plane.

[krindgen]

That prop, maybe OK in less dense water, may be too much for that motor? Same motor I run a 24P Fury (3B) with no plugs - but have run with one to protect against blow out. Have a Croxton 4B XL that I like too. That prop I need like 2/3 holes plugged. I'd like to fine tune the plugs a little more with a plug in each hole and then drill out for the correct amount of venting total needed.

[JR19]

If a prop is slow to build rpm opening the vent hole creates more air bubbles thus letting the prop slip a small amount to spool up faster. If the prop slips too much and does not want to hook up closing the holes takes away air bubbles thus letting it bite better. It does not matter if the holes are open all the way, partially open or closed all the way once the prop is hooked up zero ventilation comes out of the holes. Their primary purpose is to generate air bubbles on the sudden rush of rpm at the hole shot.


watch this video...

[krindgen]

Couple years ago I took my boat to a local high dollar Merc dealership for what turned out to be some warranty work. At that time I still had the one plug in my prop. I was there for a TPS code. Technician and the svc mgr told me they removed the plug, told me that the plug was going to have the prop running out of balance. I explained how it works. No acknowledgement. Needless to say - I don't go there anymore and make a point to tell this story as frequently as possible.

[eagleman55]

I just went thru the prop plug swaps. Ranger z519 mercury pro xs 225. all open holes would blow out and never get on plane. all plugged hard to get rpm to spin up over 2500 rpm. Ended up with 2 large hole plugs and one open now runs great with good hole shot. my prop is a tempest plus 3 blade 26P with new inner hub.

[Luke]

an easy way to test your setup to make it simple to mess with is get the solid Plugs if your lagging on holeshot take a drill and start drilling the solids out. do that untill you get where you want to be and can either leave it with the drilled out solids or replace with comparable large med or small Plugs.

[Capt James]

an easy way to test your setup to make it simple to mess with is get the solid Plugs if your lagging on holeshot take a drill and start drilling the solids out. do that untill you get where you want to be and can either leave it with the drilled out solids or replace with comparable large med or small Plugs.

Why wouldn't you simply remove 1 plug at a time and try it?

[krindgen]

Why wouldn't you simply remove 1 plug at a time and try it?

One reason, those plugs are a pain in the ba!!z to remove. Also better to have equal venting all the way around the prop. Anyway, better to start by adding plugs until it works.