F90 prop change and trim tab interference

[Ghostriderc227]

Looking for information on available trim tabs for my 2007 F90. The prop was just changed from a 13 5/8 X 13 aluminum to a 13 3/8 X 15 Stainless. After the installation of the new prop I found an interference between the prop and the zinc anode or trim tab. I have given thought to modifying the old tab to allow clearance but would also like to find the trim tab that would fit this engine prop combination without modification.

After searching Yamaha trim tabs I am now more confused than when I started. There are literally dozens of different trim tabs out there for the Yamaha outboard; my hopes are to find someone who has encountered this and found the solution or at least the part numbers that would cure the interference and have no negative impact on steering pull or performance.

Thanks in advance for any feedback, solutions, information.

Steve

[robert graham]

Probably best to just take the grinder and the file and modify your trim tab to provide clearance. Good Luck!

[99yam40]

13 5/8" original prop is larger than the 13 3/8" replacement.
How can a smaller diameter prop cause this problem

[Ghostriderc227]

Prop interference and trim tab

Yes.....the new prop is 1/4 inch larger in diameter.....but it also has more pitch; thus the blades extend rearward farther than the original prop. This moves the blades rearward far enough to just interfere with the trim tab.

13 5/8" original prop is larger than the 13 3/8" replacement.
How can a smaller diameter prop cause this problem

[Ghostriderc227]

Thanks for the reply Robert.

That is exactly what I did yesterday and it works fine. The soft metal made for easy work with a file. I cut a notch about 1/4 inch rearward and shaped the leading edge to match the rest of the tab. I think this will work perfect.

Steve

Probably best to just take the grinder and the file and modify your trim tab to provide clearance. Good Luck!

[99yam40]

Yes.....the new prop is 1/4 inch larger in diameter.....but it also has more pitch; thus the blades extend rearward farther than the original prop. This moves the blades rearward far enough to just interfere with the trim tab.

OK, so the original post was stated wrong. "The prop was just changed from a 13 5/8 X 13 aluminum to a 13 3/8 X 15 Stainless."
What kind of boat are you running it on and what are the WOT RPMs with the old and now with the new prop?
I would have thought a 15 to 17 pitch would have been original, but not a 13, but depends on the boat and load