looks like machine marks left from 'cc'ing the head(an operation preformed to ensure that both combustion chambers are exactly the same size to achive even preformance...nothing to worry about
probaly done during a rebuild basicly it involves placeing the heads cumbustion chamber side up with spark plugs installed sealing the top with a glass plate that has a hole in it and filling the chamber with precicley measured volume of liquid to ensure they are exacxly the same volume thereby providing even compression ,power ect..if they are not even material may be removed from one or both to acheive the precice combustion chamber volume desired...on rare occasions material may be added by welding in order to decrease volume thereby raising compression..
Maybe I'm missing out here, but of all these motors I have owned, I never had a problem starting or running them as they came from the factory if everything was set up properly.
I guess I am too 'cause I've worked on a lot of 6 hp mtrs over yrs and never had a prob if they were properly tuned. I don't think the bean counters at the factory would spend the extra $$$$ to do something like that on a 6 hp mtr.
I was hoping to be able to use the cc'd head on the other engine as the other head does not allow a spark plug to properly seat. It it useable or should I find another head?
no problem using it...or as boobie said clean up the threads on the other, its six of one half dozen of the other as long as their not warped either would work fine........
I guess I am too 'cause I've worked on a lot of 6 hp mtrs over yrs and never had a prob if they were properly tuned. I don't think the bean counters at the factory would spend the extra $$$$ to do something like that on a 6 hp mtr.
ive never seen it on a factory engine this small either but have when its been rebuilt by someone whos a bit anal about their work,ive got aneihhty two 9,9 that was rebuilt by a previous owner who happened to be a jet turbine engineer and its been balanced ,blueprinted,portmatched and cc'd it runs so smooth and quiet people think its a four stroke....im kinda glad he was so anal
