The old Yammie 60 2-smoke started getting an overheat alarm at idle and at WOT on longer runs a few weeks back, so I replaced the impeller. The old one was still Ok, which was curious. It was also spraying out water at a good rate from the cooling peephole.
Then go to replace the thermostat and see it was cored out by the previous owner, so it was always flowing water. Meaning, it probably ran too cool at times and would be harder to warm up, but that couldn't be causing overheating. I replaced that, but noticed a Lot of scale when in the housing.
So I ran some CLR through it, which while not the best performer was also generally considered safe enough for the aluminum. That also didn't help. I also got a new overheat alarm, but notice it is sort of wedged under the edge of the head water jacket plate into the head cover. While researching that and descaling, I see s ton of videos about how much crud and scale build up inside outboards with their open cooling, so I figure a 23 year old outboard Needs a physical cleaning and descaling.
I ordered the head and head water jacket gaskets and go to work. And of course, 4 of the 14 head bolts snap off in the block. Of course. Could have been worse: they were all higher up on the block and easily accessible. I ordered replacements and picked a weekend to remove the bolts and did a lot of scrubbing with brushes and a dremel to remove crud and scale from all the accessible water passages. None were blocked, but there was a lot of crud and scale to wire brush off.
I then go after the broken bolts, and that's where the fun begins. I started with the worst one broken off about 1/8 inch deep. First I try to drill it out, and back it out with an easy out after a lot of heating with a butane torch. Nothing but fail. Bigger hole, bigger east out. Nothing. Won't budge. Then: snap. The damn tip of the east out breaks off in the hole. They are super hard steel and as hard as the drill bits I have, so it won't drill out. These are m8 bolts so they aren't very big, either. Not much to grab.
So I decide to use the weld a nut on technique to get it out. I figure the easy out is steel so it will just become part of the weld, and back out with the rest. After a couple of hours of work with my wire feed welder and several 1/4" nuts later, I get nowhere. They all snap off. I then decided to try my stick welder with some 7018 rod. I figure a bit more amps and the nice smooth 7018 weld will get a good contact with the bolt remains and get it out. I position a nut with pliers over the bolt hole and strike the arc and it goes fast and gets orange and in a couple of seconds I have a good weld in the nut, seemingly. I chip the slag and verify, then try to spin it out, and it snaps off again. F!
Then I see why, part of the molten steel underneath the nut had gotten hot enough long enough to melt the alloy block whee it was thinnest along the inside edge and had basically flowed into that spot, replacing it. If I had welded any longer, I might have destroyed the inner wall of the block in that area, so I was very lucky actually. I was at first very dejected as I thought I might have compromised the block, but then I realized I could clean it up with careful dremel work and the burn though metal had basically replaced the area it melted out. I'd never get that bolt/broken tip out whole now, but I could still drill it out and re-tap it.
Some research and I discovered carbide and diamond tipped tools could grind down that broken extractor tip, so I made a hardware store run, and came back with a fresh set of normal and left handed drill bits, a few new masonry/tile carbide bits, and a diamond dremel grinder tip, and a carbide dremel burr tip.
The dremel tips and the carbide tile bit did the trick, slowly and methodically grinding away the extractor tip after I had fully exposed the base of it by drilling out the previous weld attempts. I ground it down, then noticed a curious lack of resistance. WTF? The remaining tip was now spinning loose in the hole! I could not now grind it any more. After some careful work around the hole edges, I was able to widen the hole so the there was room to get the extractor tip out, but it took about 10 minutes of prying with a pick to flip it up out of the hole. Success!!
I then drilled the hole out to depth with some left handed bits, hoping they would spin the bolt remnant out at some point, but that never happened. What did happen, however, was that just when I had drilled completely to full depth and was widening the hole for re-tapping, the MF drill bit tip broke off in the hole!!!
That's what I get for tempting fate and asking "what else can go wrong?". Keep in mind I am working in a 7mm wide bolt hole with 47 year old eyes. I can see the tip in there and it's wedged, but it wiggles a bit when I push it with a pick, so it might be extracted with care and enough force. Otherwise I would have to dremel grind it out because you can't drill a drill bit with the same grade of drill bit. By some miracle, however, I had a small stainless steel hemostat that would fit down the hole with a tip small enough to open and grab the bit at the flutes. About 10 minutes of grabbing, twisting, and pulling at the bit, it finally came loose. (Yeah, that's what she said!). But seriously, it was euphoric. I was finally able to drill out the bolt hole, and carefully re-tap it, trying my best to find the original threads if I could.
I verified the results with a head bolt, and it had worked!
One down, three to go.
Fortunately, these did not fight back as hard, and I went for what had worked: center punching the old bolt remains, drilling it out with successively bigger bits, heating and trying a left handed bit to see if it might spin out in the process, then I if that failed, drilling out to the tap diameter, trying to pick the old threads clear at the top, then tapping the hole out with new/cleaned threads.
I only broke off one more bit tip doing all that but it came back out more easily than the first one.
8 hours of work including the shopping and a lunch break, but I can put it all back together now, cleaned and descaled.
And that is why boat shop repairs cost so much. Imagine dealing with this bull**** 5 or 6 days a week. It should pay well.
Then go to replace the thermostat and see it was cored out by the previous owner, so it was always flowing water. Meaning, it probably ran too cool at times and would be harder to warm up, but that couldn't be causing overheating. I replaced that, but noticed a Lot of scale when in the housing.
So I ran some CLR through it, which while not the best performer was also generally considered safe enough for the aluminum. That also didn't help. I also got a new overheat alarm, but notice it is sort of wedged under the edge of the head water jacket plate into the head cover. While researching that and descaling, I see s ton of videos about how much crud and scale build up inside outboards with their open cooling, so I figure a 23 year old outboard Needs a physical cleaning and descaling.
I ordered the head and head water jacket gaskets and go to work. And of course, 4 of the 14 head bolts snap off in the block. Of course. Could have been worse: they were all higher up on the block and easily accessible. I ordered replacements and picked a weekend to remove the bolts and did a lot of scrubbing with brushes and a dremel to remove crud and scale from all the accessible water passages. None were blocked, but there was a lot of crud and scale to wire brush off.
I then go after the broken bolts, and that's where the fun begins. I started with the worst one broken off about 1/8 inch deep. First I try to drill it out, and back it out with an easy out after a lot of heating with a butane torch. Nothing but fail. Bigger hole, bigger east out. Nothing. Won't budge. Then: snap. The damn tip of the east out breaks off in the hole. They are super hard steel and as hard as the drill bits I have, so it won't drill out. These are m8 bolts so they aren't very big, either. Not much to grab.
So I decide to use the weld a nut on technique to get it out. I figure the easy out is steel so it will just become part of the weld, and back out with the rest. After a couple of hours of work with my wire feed welder and several 1/4" nuts later, I get nowhere. They all snap off. I then decided to try my stick welder with some 7018 rod. I figure a bit more amps and the nice smooth 7018 weld will get a good contact with the bolt remains and get it out. I position a nut with pliers over the bolt hole and strike the arc and it goes fast and gets orange and in a couple of seconds I have a good weld in the nut, seemingly. I chip the slag and verify, then try to spin it out, and it snaps off again. F!
Then I see why, part of the molten steel underneath the nut had gotten hot enough long enough to melt the alloy block whee it was thinnest along the inside edge and had basically flowed into that spot, replacing it. If I had welded any longer, I might have destroyed the inner wall of the block in that area, so I was very lucky actually. I was at first very dejected as I thought I might have compromised the block, but then I realized I could clean it up with careful dremel work and the burn though metal had basically replaced the area it melted out. I'd never get that bolt/broken tip out whole now, but I could still drill it out and re-tap it.
Some research and I discovered carbide and diamond tipped tools could grind down that broken extractor tip, so I made a hardware store run, and came back with a fresh set of normal and left handed drill bits, a few new masonry/tile carbide bits, and a diamond dremel grinder tip, and a carbide dremel burr tip.
The dremel tips and the carbide tile bit did the trick, slowly and methodically grinding away the extractor tip after I had fully exposed the base of it by drilling out the previous weld attempts. I ground it down, then noticed a curious lack of resistance. WTF? The remaining tip was now spinning loose in the hole! I could not now grind it any more. After some careful work around the hole edges, I was able to widen the hole so the there was room to get the extractor tip out, but it took about 10 minutes of prying with a pick to flip it up out of the hole. Success!!
I then drilled the hole out to depth with some left handed bits, hoping they would spin the bolt remnant out at some point, but that never happened. What did happen, however, was that just when I had drilled completely to full depth and was widening the hole for re-tapping, the MF drill bit tip broke off in the hole!!!
That's what I get for tempting fate and asking "what else can go wrong?". Keep in mind I am working in a 7mm wide bolt hole with 47 year old eyes. I can see the tip in there and it's wedged, but it wiggles a bit when I push it with a pick, so it might be extracted with care and enough force. Otherwise I would have to dremel grind it out because you can't drill a drill bit with the same grade of drill bit. By some miracle, however, I had a small stainless steel hemostat that would fit down the hole with a tip small enough to open and grab the bit at the flutes. About 10 minutes of grabbing, twisting, and pulling at the bit, it finally came loose. (Yeah, that's what she said!). But seriously, it was euphoric. I was finally able to drill out the bolt hole, and carefully re-tap it, trying my best to find the original threads if I could.
I verified the results with a head bolt, and it had worked!
One down, three to go.
Fortunately, these did not fight back as hard, and I went for what had worked: center punching the old bolt remains, drilling it out with successively bigger bits, heating and trying a left handed bit to see if it might spin out in the process, then I if that failed, drilling out to the tap diameter, trying to pick the old threads clear at the top, then tapping the hole out with new/cleaned threads.
I only broke off one more bit tip doing all that but it came back out more easily than the first one.
8 hours of work including the shopping and a lunch break, but I can put it all back together now, cleaned and descaled.
And that is why boat shop repairs cost so much. Imagine dealing with this bull**** 5 or 6 days a week. It should pay well.