Mercury 2.5 power head stuck on exhaust plate adapter

[Seanj85]

Anyone have any tips on getting a power head off on a 94' 200? I have the 10 nuts off and get the power head free. :confused:

[Markus]

Studs are stuck.

Ideas (can be combined)

1. Lots of 5-56, heat and vibration might help
2. Hang powerhead in shop hoist
3. Put nuts back on, but something hard between nuts and mid (if there is room - you can do it on an offshore mid), and turn nuts down to push studs up

[Black Outlaw]

Weld the nuts to the studs and then you can remove the studs from the block if that doesn't work it can get serious

[Seanj85]

I've heated all of them a few times and tried turning the nuts down on a spacer wherever possible to push the block up like Markus recommended but have had no luck. will the studs unscrew or are they pressed in??

[Black Outlaw]

Studs will unscrew from the block. They may have loctite on them though so after you get the nuts welded on put a little heat on the block where they thread in to loosen the loctite

[outasite]

Problem is they are stuck in the mid housing.If you weld a nut on and try to turn they would most likely break off just below flush.If you have an old Lincoln buzz box welder,you can attach one lead to the end of the stud the other to a good ground on the block,go to the pipe thawing setting mode (75amps)I believe. Give it a few seconds, and check.It should heat the stud only.After a few cycles they should become loose enough to pull free.---Make sure the lead on the end of the stud is not touching the housing.

[Black Outlaw]

Most of the time even though they are stuck in the adapter plate they will turn out.

[Donat]

Cut studs of thru exhaust plate and save yourself aggrivation . Get new plate. It's cheap if it's 2 piece. Or weld the cut. Use thinnest blade u can find. It's the 2 long back studs that won't let go on salty engines...

[Black Outlaw]

Cut studs of thru exhaust plate and save yourself aggrivation . Get new plate. It's cheap if it's 2 piece. Or weld the cut. Use thinnest blade u can find. It's the 2 long back studs that won't let go on salty engines...
I drill straight thru the adapter plate and into the side of the stud and cut the stud by drilling through it then I tig the holes up. I have been doing this on yamahas for years did my first 2.5 this way last year

[flabum1017]

Air hammer on the studs, the idea is to vibrate the corrosion out....... it will start snowing on ya, do that for every stud and with the power head being lifted......just as it starts to move, cut the mushroom off the end of the studs and heat, it will come right off

[Go Time]

I do the same as Black Outlaw, it is the quickest and always works. Plus if you do a clean job drilling through the plate and studs, the adapter plate can be recovered with a little welding. This subject is discussed here every couple of months and you have your heat guys and your drilling cutting guys. both methods have worked.