Re: cylinder head concern
I see you posted this a while ago and haven't had an answer. So, you were drilling out the broken bolt and drilled through it and into the combustion chamber, right? Did you get the bolt out after drilling this hole?<br /><br />Here's what I'm thinking. I believe you can probably work out a plug of some kind. It's worth a try. If it fails, a new head will be needed. If it works, you'll save some bucks.<br /><br />What I see happening here is a job that will require tapping the hole...possibly redrilling to enable the right sized tap. Then, using the proper loctite sealant (I don't know which one, frankly, it will be a high-temperature non-removable variety), screwing in a straight allen-headed set screw of the proper size and length to allow reinsertion. of the thermostat cover bolt, with the sealant providing the seal and locking of the setscrew.<br /><br />That done, whatever part protrudes into the combustion chamber will have to be carefully dressed to match the contours of the chamber. High speed air grinder, used by someone who has done such things before.<br /><br />That done, the thing gets reassembled. My guess is that it should hold just fine.<br /><br />An alternative would be to have someone weld the mistaken hole to fill it...using the appropriate filler material. Again grinding to match the combustion chamber. I'm not big on welding aluminum castings, but that's another possibility.<br /><br />Seems worth a try to me, but finding the right person to do the work is the iffy part. They'd have to know their business.<br /><br />You might want to check the price of a replacement head, first, though, through tcoutboard.com or another outboard junkyard. It might not be too bad.
