Input sought on removing badly corroded 25 hp. powerhead

[AlTn]

1971 25 hp. Evinrude < 25102S >...salt water engine..powerhead screws so corroded it's hard to determine if they have a head. I need to remove the powerhead to get to the shift shaft as the slotted portion that the shift handle adjustment screw goes through broke. Welding shop couldn't repair it in place as they can't get to the back side of it. Dremel the heads off the screws and pray? I can't see how to get a drill in those spaces to drill them out even with the screw heads removed? Any and all ideas appreciated.

 

[Mas]

Re: Input sought on removing badly corroded 25 hp. powerhead

If the heads are gone, I would dremel them off and remove the powerhead. By just removing the heads, you'll leave part of the shank that you should be able to grip with vise grips. But first, heat the crap out of them. May have to knock the powerhead with a mallet.

I'm not visualizing exactly where the screws are on your motor, but that my thought.

Mas

 

[jere1972]

Re: Input sought on removing badly corroded 25 hp. powerhead

I just went through this with my 72 50hp I picked up, the problem was mine were not bolt heads but nuts on long studs they looked like carrige bolt heads at this point, so I cut them completely off with a dremel (nut portion only), thinking I could just pull the power head,,, NOPE!!!!!!! there was so many years of corrosion the studs and exhaust adapter housing became one, was able to get 4 of the six longer ones out by hitting the tops of them with a air impact hammer to loosen the corrosion, then cutting a slot in the stud and using a impact screw driver, but the last 2 would not budge, so I sacrificed my housing cut it off around the studs, onces power head was removed studs came out easy but now the adapter housing is shot, so its a parts motor on craigslist now. So man good luck! these old engines are a pain if never disassembled in 40 years! not sure on the 71 25hp but if anything like a 72 50hp, I feel for ya!!!!

 

[F_R]

Re: Input sought on removing badly corroded 25 hp. powerhead

Sometimes, with undersize hex head fasteners, you can use a metric wrench or socket (6-point). 12MM on 1/2" bolts works often.

 

[1946Zephyr]

Re: Input sought on removing badly corroded 25 hp. powerhead

Ford 360/390 exhaust manifold bolts are absolutely the worst for "becoming one" LOL

 

[F_R]

Re: Input sought on removing badly corroded 25 hp. powerhead

Ah yes, the Ford 390. I ruptured a disc in my back while lifting the intake manifold off one of those. That was about 40 years ago, had surgury to fix it and it still hurts to this day.

Oops, getting off topic here. Sorry.

 

[AlTn]

Re: Input sought on removing badly corroded 25 hp. powerhead

I really appreciate the input and here's the status update....assesed the likelihood of removal w/o collateral losses and decided on another approach...with the help < more than help as he's making the piece > a buddy and I decided to make a piece to replace the fan shaped portion of the shift shaft that allows you to adjust the shift linkage where the shift handle attaches to the shaft. This new piece will be held to the shaft with a pinch bolt. Sure hope this allows the adjustment to bias itself towards forward gear as it is currently biased towards reverse and will not stay in forward for much more than 3 seconds at off idle throttle settings. Will report back with results. Thanks again.
With regard to the 390 intake...my wife's uncle concurs completely...seems like he said it weighed in the neighborhood of 75 lbs. Wouldn't you think they could put brass nuts on the exhaust manifold studs so you could at least twist them off when they had to be removed?