I bought a little boat with a Mercury 20 Jet motor on it. Before I run it, I want to change the water pump impeller.

I go to loosen the bolts on the bottom and several don't want to budge. I can see where they are a little rounded from an effort by the previous owner.

Here is what I have done:
1) rounded the bolts off more
2) PB blasted them a couple times
3) Tapped a socket extension with a hammer against them pretty hard
4) Used the full power of the Dewalt impact drive against the 2 I can get to with no movement.


My next step is the apply heat to the area that the bolts thread into, not the bolt itself. My 2 concerns are

1) The whole process (how long to heat, how many times, when to pb blaster, will propane torch work, when to try to loosen the bolt)
3) Is there anything I am going to hurt heating it up and cause myself more problems (gaskets, seals, etc.) The picture below points to the bolts I am trying to remove



If the picture is not clear enough, there are 5 bolts that hold the grate on, 2 on each side and 1 on the front. Those bolts are screwed straight up in to the section above the grate section. Since the bottom flares out, the bolts are a little tough to get to with all tools. I think with my impact and a 1/4" pivoting socket adapter I can get a 6 pt socket on at least 4 of them.

I know some of you guys have wrestled through this.

Carry it to the experts. If they break it they're responsible. Besides I'm sure they have done it before and know a few tricks.

Paging Mirage... Ohh wait.. Never mind, Carry on

Try Kroil on them or Fluid Film.

Haha. That's exactly what I was thinking

I think you have Fubar the bolts.

So you take tore up junk to a mechanic and expect miracles? It aintike they are the ones who rounded the nuts off to begin with.

First of all it ain't tore up, YET. The nut is rounded enough and froze enough that a wrench won't grip it enough to break it loose. A 6 point socket will still grab it.

For the record I do take tore up stuff to mechanics expecting miracles.

the trick to heating it would be to heat around the bolt as fast as you can without heating the bolt a big rosebud helps. If you can still get an impact on it that would be good. I assume you are talking about a 1/2 dewalt 120v and not the battery powered one. If not lock a pair of big vice grips on it at strike with a hammer. some of the locktite has to be heated to 350f for the bolt to come loose. If all else fails start drilling holes through the middle of the bolt. start with a small bit and work up. just make sure its perfectly centered.

Have you tried cussing it yet?

Bust the heads off the stuck ones and drop the foot. It will take the pressure off the stuck bolts and also allow for the PB Blaster to run down the threads. You may still have to use heat to help the PB get pats the corrosion. I know it sounds crazy cut the heads off, but I've had them stuck before and as soon as the pressure was off it was easy sailing. I've also had to drill and tap some, but either way, they have got to come out.

The way it's sitting now, the bolt head and metal are making a seal preventing the lubricant from getting to the problem.

A piece of cheater pipe about 3' over your rachet or wrench handle with steady hard pressure does less damage in my experience over all the impact tools and beating aimlessly. And they will break loose with a cheater pipe. If not then you still have the destruction posted above to fall back on. Outboard foot bolts are stainless on mercs usually so they are going to be hard to break off. They should take the pipe as good as Troxs wife.

What TC said, I would add its probably casted aluminum so I would not heat it much or at all imo. The bolts should also be stainless for marine application. Use a good box end and cheater with hammer to jar them loose.

Cheater pipe should've been tried early on. Maybe he hasn't, but with everything else he said he had tried I figured he had. Maybe not though.

I started with a box end 3/8" wrench. Since the box end only applies pressure to 2 sides and some of the bolts had been boogered already, it just slipped after a little pressure.

The head of a ratchet is too large to fit in the location and get a socket on the nut straight.

I bought some pivoting socket adapters earlier and am going to give it another go this evening. I am a little scared to throw a cheater bar on it with these bolts only having a 3/8 head.

No matter who gets the bolts out or fails, what you have is steel bolts and threaded aluminum that they are screwed into. They are galled (seized up due to different properties of the 2 metals).

If it were mine I'd take it to a professional. Now that the heads are rounded off they will tell you that (A) they can try or (B) they can get them out but no guarantees on what the cost may be. If you tell them to go for B and get them out regardless they may crack the housing.

This could have all been avoided if somebody had put anti-sieze goo or axle grease on the threads before reassembling the thing.

Are they bolts, or are they studs with nuts on them? I don't fool with those little motors, but all the V6 Mercs use studs and nuts.

all the above will work or try these

http://www.zoro.com/i/G1991963/?utm_sour...m7Aod8jEAxwwill

What about a 6 point box end wrench? if a six point will still work.