Powerhead won't pop off? 2 rear nuts, Evinrude 100hp 1972

[ILLaViTaR]

Hey guys, well as some of you may know from my other thread I need to replace the spaghetti seal in the crankcase, the powerhead is almost ready to come off, I'm just having trouble with the mounting bolts.

I have the factory repair manual that's been helpful until this point. Basically There are 2 nuts and 2 bolts up under the swivel bracket that needed to come out, they were rusted to death I so grinded them off.
Now directly below that there are 2 plastic covers (held in by 4 big phillips screws). I removed the screws and these covers won't budge. I ended up snapping the small cover by prying it and I realised it was held in by one of the mounting screws behind the bigger U shaped cover (thanks repair manual:facepalm. I realise this U shape cover needs to come off before the smaller one, none of this is in the manual, it jsut says "remove cover" which is basically useless as it doesn't tell me how. Anyone know what I'm missing? I don't understand how to get the big U shaped one off.

 

[emdsapmgr]

Re: Powerhead won't remove? Evinrude 100hp 1972 (100293R)

Re: Powerhead won't remove? Evinrude 100hp 1972 (100293R)

That u-shaped rear exhaust cover has screws which are accessed from inside the cowling. Specifically, the lower cowling. A 1/4" drive socket set should work. On the powerhead-you will be looking for two more nuts at the back of the engine and 3 long bolts that screw up into the powerhead on each side of the exhaust housing. You may find the factory exploded parts diagram helpful at this website: epc.brp.com

 

[ILLaViTaR]

Re: Powerhead won't remove? Evinrude 100hp 1972 (100293R)

Re: Powerhead won't remove? Evinrude 100hp 1972 (100293R)

That u-shaped rear exhaust cover has screws which are accessed from inside the cowling. Specifically, the lower cowling. A 1/4" drive socket set should work. On the powerhead-you will be looking for two more nuts at the back of the engine and 3 long bolts that screw up into the powerhead on each side of the exhaust housing. You may find the factory exploded parts diagram helpful at this website: epc.brp.com

Hey thanks, I found them after clearing all the dirt and grease away and the cover came off no problems. The power head is about to come off except I've hit a snag, those 2 nuts at the back are just as rusted as the other 6 long screws, difference is I can't hammer a socket on these like the others or angle grind them off, as they're much harder to access. A wrench/spanner looks like the only option yet the ring on the wrench won't fit around the nut because there's no room even for that. I can't figure out how to get it off. Any idea how I get these off?
Cheers

 

[emdsapmgr]

Re: Powerhead won't remove? Evinrude 100hp 1972 (100293R)

Re: Powerhead won't remove? Evinrude 100hp 1972 (100293R)

You could try to crack the nuts off, by using a steel chisel. You need to be careful-you don't want to damage any other aluminum parts in the process. Maybe a better way: If you have Dremmel tool, you might be able to cut the nuts vertically so that they will loosen up. You will probably damage the bolts in the process, but they are just double-ended threaded studs, which you should be able to turn out once you get the powerhead off.

 

[F_R]

Re: Powerhead won't remove? Evinrude 100hp 1972 (100293R)

Re: Powerhead won't remove? Evinrude 100hp 1972 (100293R)

Get a better wrench. I've had lots of those things apart and never had any trouble getting a wrench on the nuts. Hint: if the 1/2" nuts are rusted/undersize, use a metric wrench. 12mm if memory serves correct.

What is worse, if it is as bad as you say, the studs may be corroded in the adapter plate. You may not be able to get the powerhead off once the nuts are off.

 

[ILLaViTaR]

Re: Powerhead won't remove? Evinrude 100hp 1972 (100293R)

Re: Powerhead won't remove? Evinrude 100hp 1972 (100293R)

I bought a 1/2 wrench today which was too big, 12mm didn't even work so I'm going to try a 3/8 tomorrow, and then the chisel as a last resort haha. There were a few other nuts like this under the powerhead, all of them including this one seem corroded to the adapter plate, however the threads are coming free on the others so I'm hoping these two are the same. The power head is actually separating at the front, so once these 2 rear nuts are out it should hopefully pop off with ease. I also bought a butane torch which might be worth a shot?

 

[ILLaViTaR]

Re: Powerhead won't remove? Evinrude 100hp 1972 (100293R)

Re: Powerhead won't remove? Evinrude 100hp 1972 (100293R)

Well the wrenches didn't work, I figure the size I need is around 11.5mm which I can't find anywhere. I don't have any dremel tools but I've heard of these wrenches that grab the bolt more the harder you turn them, I don't mind stuffing the nut as it needs to be replaced anyway, would one of these special tools be best for the job?

 

[AlTn]

Re: Powerhead won't remove? Evinrude 100hp 1972 (100293R)

Re: Powerhead won't remove? Evinrude 100hp 1972 (100293R)

I've used some of those from Craftsman...Bolt Out...low profile..part no._9 52166..the set fits 3/8"-19mm..not sure of the clearance you'd need to get on the nut but it takes a 5/8" socket to fit over the nut/bolt remover

 

[F_R]

Re: Powerhead won't remove? Evinrude 100hp 1972 (100293R)

Re: Powerhead won't remove? Evinrude 100hp 1972 (100293R)

Are you using a 6 point 12mm wrench? If that won't get it, then it is bust-a-nut time.

 

[dazk14]

Re: Powerhead won't remove? Evinrude 100hp 1972 (100293R)

Re: Powerhead won't remove? Evinrude 100hp 1972 (100293R)

Time to post a few pics.

 

[ILLaViTaR]

Re: Powerhead won't remove? Evinrude 100hp 1972 (100293R)

Re: Powerhead won't remove? Evinrude 100hp 1972 (100293R)

Get a better wrench. I've had lots of those things apart and never had any trouble getting a wrench on the nuts. Hint: if the 1/2" nuts are rusted/undersize, use a metric wrench. 12mm if memory serves correct.

What is worse, if it is as bad as you say, the studs may be corroded in the adapter plate. You may not be able to get the powerhead off once the nuts are off.

Well I managed to get the nuts off with a cold chisel but as you said, the threads are seized to the adapter plate. And of course it's only these 2 threads, all the others are free.
I've hit them and everything but they're seized on pretty well and wont budge (hard to get a good hit on the angle though). Tried a butane torch too with no luck. Anyone know any other ideas? It's got hoist and everything on it atm, I was just expecting it to lift off haha. I'll put pics up if that helps?

 

[F_R]

Re: Powerhead won't remove? Evinrude 100hp 1972 (100293R)

Re: Powerhead won't remove? Evinrude 100hp 1972 (100293R)

I wish I had a good reply for this one. Can you get your hands on an acetelyn torch? You need really hot heat. Grind a cold chisel to a knife shape and drive it in it as a wedge (with help from the hoist) when you get the adapter as hot as you can without melting it. You may have to destroy the adapter plate before you are done. Better than destroying the powerhead.

 

[AlTn]

Re: Powerhead won't remove? Evinrude 100hp 1972 (100293R)

Re: Powerhead won't remove? Evinrude 100hp 1972 (100293R)

fwiw...checked marineengine.com and the adapter plate is still available at $90 if worse comes to worse

 

[dazk14]

Re: Powerhead won't remove? Evinrude 100hp 1972 (100293R)

Re: Powerhead won't remove? Evinrude 100hp 1972 (100293R)

pics still will help. Are all the fasteners off? Are you saying corrosion on studs is what is holding it?

 

[ILLaViTaR]

Re: Powerhead won't pop off? 2 rear nuts, Evinrude 100hp 1972

Thanks, I was really hoping I wouldn't have to destroy it but if worst to worst guess I have to. Yes the studs are corroded to the plate, the powerhead is coming away from the front with ease, here are the problem studs:

I've got an idea, I'm thinking of a tool that may not exist. Some sort of expander (works kind've like a puller) where I'd sit it between the bottom of the stud and the adapter plate, expand it until the force pops the studs up through the plate? Does such a thing exist?

EDIT: If you're wondering why the exhaust cover is still on, it's because half the bolts are seized on and will strip if any attempt is made, hoping I'll never have to open it haha.

 

[F_R]

Re: Powerhead won't pop off? 2 rear nuts, Evinrude 100hp 1972

Been there, done that. I once tried making one with a piece of steel and a bolt, like a screw jack, but it didn't work. At least the one I made didn't. It would take some serious force to jack those things out of there if they have seen salt all these years. Maybe you will get lucky and yours won't be as bad. Worth a try.

 

[ILLaViTaR]

Re: Powerhead won't pop off? 2 rear nuts, Evinrude 100hp 1972

Been there, done that. I once tried making one with a piece of steel and a bolt, like a screw jack, but it didn't work. At least the one I made didn't. It would take some serious force to jack those things out of there if they have seen salt all these years. Maybe you will get lucky and yours won't be as bad. Worth a try.

Haha a micro jack would be perfect! I was just thinking... I'm tearing it down to remove the crankcase and replace the spaghetti seal, not for a rebuild. Is it possible to get the crankcase off the way it is? I realise it's not practical but either is stuffing an adapter plate. (which foresight tells me I'll end up doing anyway haha, but I want to at least try these things first just in case).

 

[F_R]

Re: Powerhead won't pop off? 2 rear nuts, Evinrude 100hp 1972

Nope, you can't get the crankcase off without removing the powerhead. How about just letting 'er leak??

 

[boobie]

Re: Powerhead won't pop off? 2 rear nuts, Evinrude 100hp 1972

I've also have taken a small socket and put it under the stud and then used the proper size crow bar between the socket and the stud and pushed down on the bar to lift the stud up. Last option, marine-tex or jb weld on the leak.

 

[dazk14]

Re: Powerhead won't pop off? 2 rear nuts, Evinrude 100hp 1972

Has the powerhead lifted off in any places? Have you started using any wedges? If the threads are still servicable, you can use fully install a "Coupling Nut" to the studs and wedge - by loosening -onto a socket below.

With pressure applied, you other techniques will be more effective.