Re: JW10 carb kit and impeller
Aw, that ain't so bad. Not around here anyway!<br /><br />Heat is the magic bolt remover. Really, it's the only thing that works worth a damn. Use MAPP gas if you can, propane takes forever to get things warm enough. It will get those two remaining bolts out. With the amount of acess you have to the corrosion, penetrating oil may help a bit. Honestly, I think it's pointless most the time.<br /><br />The very worst thing you can ever use on an outboard is an EZ-Out. They almost never work, and when they fail you're stuck finding a machine shop with an EDM drill machine to remove the EZ-Out for you. They are a curse on the desperate.<br /><br />The right one will need a different tactic. There's a few to chose from. <br />You can weld a nut to the stud if you've got a welder. The heat of welding can often break the corrosion's bond so the stud turns out freely. The aluminium isn't a problem since it's so conductive to heat, it will just sit there with a glowing stud in it. That is, unless you hit it with the arc direct naturally.<br />I often give this a try because it's easy for me and it works occasionally. The consequences are not bad - if the nut twists off, I'm just back to square one.<br /><br />Next step is to drill out with the intent of leaving the aluminium untouched. For this you need to centre drill the bolt precisely. That means getting the top of the bolt flat with a file as best you can and centre punching it, and then running in with a 1/8" drill bit nice and square. Then increase the diameter of the bit until you just reach the minor diameter of the bolt (around a #7 bit or 13/64). At that point, only the screw's threads remain in there and you can free them by tapping them loose with a small hammer and tiny slot screwdriver until you get a tab to grab. Then just wind the old thread out. <br />If at any stage you detect movement in the bolt, count yourself lucky and wind it out. Bang in an allen key or whatever fits. This is the only time an easy out type device can be considered. If you wind off centre with your drilling, it's best to attempt a repair. I have a tiny carbide mill for my dremel tool that works prefectly for this.<br /><br />If that isn't going to work, then keep drilling up and install a heli-coil. Most professionals jump right to this step since time is the overriding factor. You may want to too, but getting the the hole on centre is still crucial.<br /><br />Some people will instead of using a helicoil, simply drill and tap for a larger screw. There's a few good reasons not to go that route in this case. One is you'll need to drill the head too to fit the larger screw, and second you'll have to use a different torque setting to get the same clamping force on the head. It can be done, but it's an ugly solution.<br /><br />The block is just the same as the 4hp. It even has those two posts on the top although they're unused on the later engines. If you stick a screwdriver or drill or whatever into the hole on the top port side of the block, just at the top of the water passage, right above the exhaust area you'll see that the screwdriver runs right through into the cylinder jacket. But then it continues, right to the passage on the starboard, which goes down the block.<br />But it looks like the top passage at least is clear. Probably the bottom one is too, but feel in there with a pick.<br /><br />I'll leave it to you to decide if you want to do it or not. Usually it's not very difficult and really requires more patience and care than skill. It is time consuming. Accept no advice but from people who work on marine engines - it really does not compare to the sort of troubles encountered anywhere else. Rusty auto exhaust parts are simple by comparison.<br /><br />Check and de-warp the cylinder head. I often find them in need of a little bit of surfacing. This is just the hand surfacing where you're at best taking off a couple thousandths: use no power tools.
<br /><br />You know, I've got an exact same exact drill stand.