Thread: Welding up a Yamaha 2 Stroke Block

A Bud that builds Racing Outboards brought me this block. I saw it a few months ago and told him I thought I could fix it. My Bud blends this area to improve flow but this block was very thin from corrosion.



Being Cast I need to use a filler that has a bit of Silicone in it, wets easily, and not prone to cracking. 4043 Alloy in 1/16th inch will melt fast, wet out well flowing over the damaged area, and remaining there forever.



To ensure a positive flow of 4043 into the substrate I use my TIG machine set to 65 amps, 50/50 Argon Helium gas mixture set to 20cfm, 65% polarity (heavy cleaning), 75Hz Frequency, and instant on - no foot pedal ramp - instant 100% 65 amps. This lets me either burn off contamination or flow it. I took the pictures before going all the way around so you can see how I'm stitching a layer of good alloy over the damaged area a arc at a time. I pop it, fill it, and get off it within a second. Got to move fast or the damaged metal will fall out.



Now this can't be blended down enough to match the flow of the other Ports but it can be placed into service for a "Daily Driver" so to speak saving a very expensive Engine Block. My Bud will do the dressing, he is a professional at that.



Much more metal around the damage to support the repair.