Cavitation/Exhaust ring on trophy plus?need help

[Fishaholic_Chase]

We have a 225 vindicator on a 1996 Stratos 201 pro XL with a 24 trophy Plus and no matter what we do to the PVS plugs or the engine height it will not wind up at hole shot it just barely climbs out of the hole my guess is that there is Exhaust escaping from around the barrel of the prop because of It’s smaller diameter than the lower units diameter . You would think that it would blow out but I think instead of the gases being shot up onto the blades by the pvs plugs it is just running along the root of the blades and still causing it to hook up well.The over hub ventilation causes low back pressure inside the barrel that would prevent the Pvs plugs from blowing gasses up onto the blades. This is just my theory we have ordered a cavitation ring for the trophy plus. Any ideas of why the prop is hooking up so well? Thanks

[billnorman1]

I'd say you're on the right track. I tried a 4 blade 27 pitch on mine and was about 1/4 inch smaller on the hub than the housing and it blew out badly.

[Fishaholic_Chase]

Is this a common problem?

[Ken-Nuk]

1403-24-2021, 07:55 PM

Well i just thought I would post about some of my experience with my old boat. (201 status w/2005 Evinrude etec) One problem I had when I switched to a Evinrude M case lower unit. it would run good with a 4 blade prop with the weed ring installed, but when I switched to a 3 blade prop it was very hard to get out of the hole without the prop blowing out. The cure was installing a 3 blade prop seal That is much like the 4 blade weed guard but must be used for the magnum case because of its slightly larger case size. (3 blade prop seal part#0346462)

[willwork4fish]

It should be blowing out without the ring. I had a Trophy on an 04 Sabre/150 efi I used to have and without the ring it blew out. I got a ring from Boger and it worked great.

Not sure what's up with yours, doesn't really make sense to me. You should post this on the prop board.

[Fishaholic_Chase]

NOTE:The lower unit is not original to the 1996 engine. The lower unit on it now is from a 2000 225HP Johnson high output engine. I do not think the gearing is any different than what was on it. The lower unit does look more hydrodynamic though compared to the original one that came on that engine. Again I’m assuming that it is basically the same but I could be wrong. Any thoughts???