Broken Cavitation Plate

[todd river]

Unfortunately I do not have the pictures at this time
to post. This weekend I ran across what may have been
a submerged log/etc. I felt a hard hit, and immediately
throttled back. I have a yamaha f-150 4 stroke 2005 model.
I was very close to the dock, so I gave it some gas & on
the take out of the hole it felt different, but otherwise was
fine. My fishing partner did not feel anything. We did it again
& this time it seemed okay. Still I had a feeling there was
damage on either the boat/motor. It felt like a hard hit.

When I drove the boat onto the trailer, I noticed the damage
when I tilted the motor out of the water. It knocked a good
chunk off of the back where it flares out. In fact almost half
of the zinc anode is exposed. It was probably 5-6 inches in
length. The prop was okay, and since I did not feel anything
vibrating I think everything is okay. I still need to check &
make sure there isn't any water in the lower unit.

I wonder if they can weld a piece of aluminum or whatever metal
was on there, without having to replace the entire case on the bottom.
I am also questioning if they can weld it back with everything intact?

Otherwise if the lower unit has to be removed & the guts taken out
I may as well let the mechanic take care of it. Either way I will let my
insurance company know what happened, and will hold off filing any
claims until I know more.

[99yam40]

Take it to a Yamaha shop and have them give an estimate, see if your insurance will cover it, that is why you pay the premium. If not then look into trying to repair instead of replacing.

[todd river]

Update & Question

I went to the prop shop yesterday, and the owner said he can
repair the broken cavitation plate. He will have to find a used
lower unit & cut off the piece that he needs. He said there was
no way to make a piece that was exact & looked good. When it
was finished there would be no way to tell it was ever broken.

Now the other issue was my prop. He said it needed to be re-worked.
He wanted to know how many rpm's it would turn WOT. When I told
him 5100 he said that was to low. I have a 19 inch pitch on a 2170
blazer bay boat. He recommended a 17 pitch. The prop that I got when
I purchased the boat was a michigan stainless wheel. SO I realize
the closer I get to 6000 rpm's the better it is for the motor. What
brand would you suggest? The yamaha props are very expensive.
Also the yamaha mechanic said IMHO that a re-worked prop is never
the same. It would be $125 to re-work the prop. The actual damage
for the cavitation plate was only $250. It seems more prudent to spend
some extra $$ to get the better prop.

I did not mention that I had to make an insurance claim a few months
back when a dead tree fell across both of my boats. It totalled my
smaller skiff & did some damage to this boat. It was my neighbors tree,
but still 2 claims a few months apart is not a good idea.

[99yam40]

Your neighbors homeowners insurance would not help pay for his tree damage?

They can re-pitch props too, if you are sure the motor is running properly you should look at different prop to get proper WOT RPM.

Have you looked at the Yamaha performance site to see how they did testing a boat and motor like your and what prop they used?
Performance Bulletin Home

[todd river]

Your neighbors homeowners insurance would not help pay for his tree damage?

They can re-pitch props too, if you are sure the motor is running properly you should look at different prop to get proper WOT RPM.

Have you looked at the Yamaha performance site to see how they did testing a boat and motor like your and what prop they used?
Performance Bulletin Home

At this point my insurance company is in subrogation. I am not getting
my hopes up.

I did look at the yamaha performance site & there was a boat that
is somewhat similar. Mine doesn't have a liner & this one did. So the
weight is probably a bit more. They ran a 18 inch prop. At this point
I called the blazer factory to get there input.