Prop Rattle Solution

[kaydano]

I took the little exhaust plugs our of my Enertia prop (thanks Todd) to see how they affected my hole shot, which is what they are supposed to be for, and I had the pleasant surprise of having my annoying prop rattle go away! There are a number of Mercury props that have these little plugs. Just thought I'd pass this along.

 

[lakeliving]

Thought you bought a yamaha with the sds hub! Glad your fix worked too!

 

[BigKahuna]

Yes, I have those plugs or PVS (Performance Vent System) in my Mercury Mirage Plus but I have never touched them.......Did they affect your hole shot in any way?!?

http://www.mercurymarine.com/media/mercury/documents/PVS.pdf

 

[kaydano]

Hard to tell.  I took them out over the winter, so it's been since last summer since I ran the boat with the PVS plugs in.  I'd have to put them back in again to really be able to compare.  So, I guess that says they are not REAL noticable...

But I did notice a couple times it feeling like it was slipping, then all of a sudden the prop grabbed hard, and my head went back and I was looking up at the Bimini.  Okay, I may be exaggerating, but I could feel it...

That said, there were MANY more times where it just felt like it was slipping a lot, and I have a haunch that if I put the plugs back in, so it wasn't slipping, I'd actually be further down the lake in the same amount of time.  I suppose that's why they make 4 or 5 different plugs with different sized holes in them, so you can dial it in.

If it hadn't fixed the prop rattle though (which is awesome) I'd probably just put them back in and leave them in. 

But, I may put them in and drill small holes in them to see if I can find a balance between the slip and the prop rattle....

Jury is still out...

 

[kaydano]

I have some real data on this now, and it ain't good...

With the PVS plugs out:

Loss of 1.5 mph at 2000 rpm

Loss of 5.5 mph at 2500 rpm

Loss of 4.9 mph at 3000 rpm

Loss of 1.2 mph at 3500 rpm

There might be better hole shot, but if so, I can't tell, but it's been a year since I ran the boat with them in. I found an acceleration app finally, and will test that just before I put them back in.

That said, the sacrifice in economy is far too great at cruising speeds. I am losing 2 miles per gallon at 2500 rpm. That's a 40% loss in efficiency.

Looks like I will be buying a new hub kit to eliminate the prop rattle.

 

[Silverspeed]

I took the little exhaust plugs our of my Enertia prop (thanks Todd) to see how they affected my hole shot, which is what they are supposed to be for, and I had the pleasant surprise of having my annoying prop rattle go away! There are a number of Mercury props that have these little plugs. Just thought I'd pass this along.

I have a 24 SL with the same motor as you, and also had annoying prop rattle. At idle in gear it was really bad. I did some research and found that Mercury makes a hub kit that eliminated this issue for me. I installed a Mercury Flo-Torq IV hub kit. The hub is two piece and connected by titanium rods that allow a slight amount of "flex" between piston fires. Anyway, the problem was completely eliminated by installing this hub, and you can buy them for about 100 bucks on Amazon.Edit: Just saw your post above about buying a new hub kit. Guess you are already aware of it. Good luck!