Rusted lower unit bolts

[Resetter]

I was doing some maintenance and removed the split cowling and found that the bolts connecting the lower unit to the power head were badly rusted to the point that 1/2 of them had now bolt heads that were usable. I managed to get 4 of the 8 off and replace them w/ stainless. I attempted to use an EZ out and, you guessed it, the EZ out snapped off on the first bolt.<br /><br />Why weren't these bolts stainless to begin with? How do I get the suckers out? It it best to wait until the remaining pert of the bolt heads to rust and then chisel them flush and then pull the lower unit. <br /><br />Anyone have a good method here? I think that the 4 new bolts should keep me in business for a while.

 

[rodbolt]

Re: Rusted lower unit bolts

hello<br /> dude<br /> what year and horsepower is this? what is the bolt size? are they the bolts that hold the lowerunit to the exhaust housing or the powerhead to the adaptor?<br /> need more info. now ya know why I say ez outs are more trouble than they are worth. never attept stud removal on an outboard with an easy out here in the old salt pond area.post more info and someone can try to help<br />Good luck and keep posting

 

[Resetter]

Re: Rusted lower unit bolts

It's a 1996 48 SPL. And they are the bolts that connect the main lower housing to the power head or you may call it the adaptor.<br /><br />By the way, it got cold!!! didn't it?

 

[Joe Reeves]

Re: Rusted lower unit bolts

Resetter.... Pick up some cheap metric sockets, one of which you should be able to pound on whatever remains of the retaining bolt/nut. Use heat from a hand held propane torch on the aluminum surrounding the bolt shank. That's the method that works for me.<br /><br />As far as the name of parts... the powerhead sits upon the adapter plate, then comes the exhaust housing, followed by of course the lower unit.

 

[ledgefinder]

Re: Rusted lower unit bolts

Heat is your best friend here. Most of the castings are aluminum, and the bolts steel. They expand very differently with temperature change, so heat will often break things loose. <br /><br />After you heat it, a couple sharp raps on the bolt head (not enough to deform the head) will sometimes help.<br /><br />All that said, I betcha you end up cutting at least some of the bolt heads off. Don't worry, after you pull the powerhead, you'll have a good length of bolt to grab onto with the vice grips. Use the torch again for a while, where the bolt goes into the casting, then spray a little liquid wrench on there. Put a large pair of vice grips on there tight, and see if you can't work the bolt loose a little bit. Easy does it - you don't want to snap it off again. Usually I can get maybe 30 degrees of turn at first. Just work it back and forth a little bit for a while, usually it'll loosen up pretty quick & you can turn it right out. On the tough ones, you may have to hit it with the torch & liquid wrench a few times. <br /><br />If you have to drill it out, use a center-punch first, then start with a small left-hand bit, carefully keeping the hole in the center, and work your way up to the larger bits.

 

[ledgefinder]

Re: Rusted lower unit bolts

I gave you bad advice. If you have no reason to pull the powerhead, just leave the old bolts in there. When & if you have to pull it, as we've said there are ways to get those bolts out.

 

[rodbolt]

Re: Rusted lower unit bolts

hello<br /> resetter<br /> listen to joe<br /> change the ones you can and leave the rest until they have to come off. I usually heat them and have used the metric socket trick as well as the 8 point socket trick. when it gets to bad a 7/16ths bullet point bit and go just below the power head and inline with the bolt and drill the bolt in half. if done carefully you usually dont have to buy another adaptor. yep got really chilly. may run over to manns harbor if the wind lays off. or might zip down to the inlet for a bit of eel drifting at the bridge. who knows <br /> good luck and keep posting

 

[wayne h]

Re: Rusted lower unit bolts

heat heat heat<br />what i do is heat the bolt and cool it with a good penatrating oil like pb blaster. cooling it with oil will suck it into the threads.do that a few times it might take a while even a few days to work. i worked on 1 for 3 days and finally it came out take your time dont over force anything remember you are working with aluminum.the longer you wait the more the bolts will get stick because its not only rusting out side but its also rusting in the threads making the bolts even tighter.its takes alot of heat to heat up the aluminum on an outboard a little crack torch probobly wont get it hot enough thats why i heat the bolt instead.remember to keep cooling it with oil. if you can stand the motor on end so that the oil runs into the threads thats even better. good luck we have all been there before thats what makes it so fun hahaha. i always use antiseize on every thread in an outboard. some people dont agree with it but mine comes apart with ease every time i need to work on it.

 

[Resetter]

Re: Rusted lower unit bolts

Thanks to all. I think I'll take the patient approach here and let the remaining bolt heads rust off. There isn't enough material left to use a smaller socket and I won't have to wait too long. At least I have 4 new stainless bolts properly torqued in and that will hold me for a while.<br /><br />Rock fishin has been a little slow.