Thread: Lower Unit Bolt Stuck

After using penetrating oil, I always used a hand impact wrench - the kind you tap with a hammer. That usually breaks up the crud and gets them free. Sometimes, just using a flat punch on the bolt head and tapping will do it.

I just learned this little tid bit last week in a class that I took. Mix you up a spray bottle with equal parts Automatic Transmission Fluid and Acetone. Spray your mixture on the bolt and let it sit for 10 minutes or so, then give it another squirt and start trying to loosen it. Another trick that may work, provided there is enough room to get it in there, is to take an air hammer. Use a blunt tip (not a chisel tip or penentrating tip!) and gently hammer as many of the flat spots (the wrench flats) on the bolt head that you can get to. Don't just let the hammer wail on it full bore, be as gentle as possible and keep moving from flat to flat. Between that and the 50/50 ATF/Acetone you should be able to get it off without having to use heat. I would discourage using heat.

One other thing that may help is to put the other bolts back in. When the last bolt is holding all the load, it may be in a bind from the torque.

Another trick is to tighten the bolt. Just a fraction. Then slowly work it back and forth just a little at a time. If all else fails, heat and that method will get them out everytime.

When you get it out and get ready to put it back together....use anti-seize compound on your bolt threads. It will come apart easier then next time.

Well, heres the outcome. Had to cut the head off. got the lower unit off and finally got the bolt out. Man it was bent!!!! Two years ago i hit a stump full throttle at Lake Talquin (AKA Lumber Yard) which actually broke the top of my cowling. So, my guess is that when it got bent. Next, the water pump housing (plasctic piece) was melted into the rubber wheel. So, I'm replacing the entire parts around the water pump including the seal on the bearing. Everything else looks fine. Only issue now is although I have a tap kit i don;t have one that will tap out the hole for the mount bolt to go back in and it no doudt needs it. So, I'm looking for that tomorrow at Fastenal store.
By the way, just got home from Iraq last month so this is my Welcome Home present. Boat sat-up for a year. OK, I'll have it ready by the end of the week----maybe!

I would go to a Hardware store or Home depot for the tap Aot cheaper than Fastenal

Originally Posted by wilbur

I would go to a Hardware store or Home depot for the tap Aot cheaper than Fastenal

I need just one. I got a complete tap set (excpt the one I need) for the treads. do they sell just single taps? The treads are longer than the ones i got.