h_lankford
Petty Officer 2nd Class
- Joined
- Aug 6, 2005
- Messages
- 135
Can you identify the holes in this pic? Thanks.<br /><br />I am rebuilding a saltwater 1986 Johnson and found what looks like an extra, abnormal hole. When I lifted the block off, and looked into the exhaust adaptor, I could see a normal-appearing, non-corroded small hole approx 1/8 inch size at the bottom of the chamber (small stick). But I could also see a larger, corroded, irregular hole 3/8 to 1/2 inch size on the side of the same chamber (large stick). This would appear to take too much cooling water and empty it straight into the main exhaust. Or, depending on pressure,it might force exhaust into the coolant passage (judging by the color, the latter has occurred). This abnormality has apparently been there for quite some time. I don't know if the larger hole is all corrosion-induced, or if there was normally a small hole there that has enlarged over the years.<br /><br />The overboard indicator was ok and no known overheating. The reason for the rebuild was an instant loss of 500 rpm (running at 4500, dropped to 4000), zero compression in the middle cylinder, and parts of the wrist pin clip visible along the edge of the top of the piston (with resultant groove in that cylinder). <br /><br />I think the wrist problem was unrelated to the corrosion problem. Some crosshatching was still visible on all 3 cyl walls. VRO had been disconnected 10 yrs ago and used 50:1 instead. The engine had only 500 hrs, was used weekends in summer, and stored on lift out of water in boathouse, or in garage rest of year. Had used muffs and fresh water flush, although apparently 30 second runs was not enough. <br /><br />I have plans for the block, my question is what to do about the new finding of the hole. Should I patch it up (JB Weld or what else?, scrap the whole project? - although I am trying it "because it is there". Just for the fun of it. <br />Thanks, Harvey <br /><br /><br />
