So I have been dealing with a bit of a headache, partly because I'm pretty anal. I have an 01' Fountain Fever 29 which only has approximately 170 hrs and the boat is in mint condition. At the end of last season while I was cleaning the boat, i noticed what looked like a bubble in the powder coating on the trim tab bracket thats mounted to the boat. The bubble was on the powder coating of the bracket right where the bracket meets the gel coat. So I pushed on the bubble, the powder coat broke apart and a grey colored substance was underneath the bubble. After clearing away the powder coating and the grey substance, it looks as if salt water some how got underneath the powder coating and started to corrode the aluminum on the bracket hence the grey substance. It almost looks like it started corroding somewhat on the back of the bracket and is coming out to the edge. So my plan was to remove the bracket and blast it and paint it. Well easier said then done, what a nightmare. So I took all the bolts out that secure bracket to hull and now I'm down to just the bracket and whatever material the factory used between the bracket and the gelcoat on the hull. I've tried using 80lb power pro fishing line in between the bracket and hull to cut thru the material and I've tried hammering a spackle knife between and I have made zero progress! Like I said the boat is in mint condition and I don't want to **** up the gel coat or even scuff it. I'm looking at this saying there is no way this bracket is coming off without pulling gel coat and that's just not an option. I need advice from an expert cause no one seems to know. I'm not sure if its 5200, its whatever the factory would have used. My other question is, There seems to be aluminum exposed on little areas on the outdrive as well however it isn't corroding so why is the aluminum on the trim tab bracket. I did notice that the zinc on the bracket is a little worn away but there was def some zinc left on it. The boat sits on a lift so it isn't in the water very much so could it be that there just wasn't enough zinc on it. If so, if I just replace the zinc on the bracket, will the aluminum on the bracket stop corroding or will it continue you since it already started. When I say the aluminum is corroding, it's very minor but I'm trying to stop it before it gets worse. I just don't see how this bracket is gonna come off, what a headache.

more then likely its 5200 and good luck getting it off without some gel coming with it! I have yet to get a clean separation when 5200 is involved!!! All i can suggest is like what you already did use the fishing line, or i have used piano wire in the past, and work your way around as much as possible and get as close as possible to the hydraulic tubes that go through the transom.....that's where its hanging up as i'm sure they gooped up the holes that the tubes go through...then start to use wedges under the corners and start applying more and more pressure to try and get the plate to move away from the transom.......i can guarantee you will probably loose a bit a gel around the tube holes and hopefully that's all if you were lucky enough to cut through all the 5200 down to the tubes...no big deal as it will all be covered back up with 5200 when you re-install

Careful application of heat will help release the sealant

It is mounted with 5200 , carefully heat the bracket with a heat gun and it will help to break the bond , do not overheat or you can bubble the gel coat

When it comes time to remount the bracket use 4200. It is not permanent like 5200

When I did my tabs on my fountain, I used about four scrapers at one time and drove them in. Then went with a few thicker scrapers. Then flat head screw drivers and drove in. When it lets go, it sounded like I ripped the gel coat off. My surprise, not hardly a scratch from any of the tools I drove in there.

https://www.dremel.com/en-us/Tools/P...spx?catid=2094

This with either a scraper blade or a fine tooth blade(as long as you keep it parallel with the transom) and it will make an easy job of removing those tabs!

Try De-Bond or Un-Hesive, these products claim to be your answer to your problem.

I used what 502ss suggested on my Formula when removing trim tab brackets and did not eat into the gel. Mine is made by Fien and comes with a blade like a scraper (no teeth). Get in as far as you can all around tab and then you will have to pry it off. To answer your corrosion question, mercruiser outdrives are made of a mix of metals that resist corrosion and I'm thinking the trim tap is just aluminum that is more prone to corrosion. Good luck.