Hello! I have an 89 forester with a xr4 on the back, when I get up to speed I have issues with cavitation around 45 mph, any fixes for this? Outboard has a cavitation plate on it, and I trim it up as I gain speed. Do i need trim tabs or??
So you most likely have one of two problems, you are either trimming it up too much, or your motor is mounted too high. Pics of the back of the boat, especially from the side, would be useful.
Currently a 3 blade 19P but also have a 4 blade 20P. The 3 blade on gives me the ideal rpm range, but engine has been mounted on the boat since it was built in 89
How long have you owned the boat ? Did it always have this issue or did it just start ? Have you tried switching props to see if it's the 3 blade that's causing this or as you asked ,maybe something else.Maybe the hub is failing at high rpm's ? Is the "cavitation " plate a aftermarket add on or are you referring to the stock plate built into the lower unit ?
It's an add on plate and owned it for 1 year now and tried a 21 pitch prop but could not get to max rpms. It had a 19 before that and had same cavitating problem
Take the plate off if that cures it great. Before doing so I’d throw both props on it and compare all aspects of operation with and without the plate. My older boat had a Dole Fin bolted on it from the dealer when sold new. It did help pulling skiers when loaded but that was the only plus. I tinkered with props and found a ballistic SS is the best fit with no plate. You may find the plate serves some purpose and it may not fix your issue. Or that it has a place and time to be on maybe not. Also look for anything that’s creating a disturbance in front of the prop or a bent fin. I had a small boat that had a bent fin this thing would cavitate in the right condition you never really felt it as a performance issue but you could hear and see the foaming water in its wake.
