Marfam 1 #1 Posted December 14, 2017 My grandson just purchased a C-160 with a Tecumseh engine HH160-170019. It came in pieces and we are trying to get it assembled so we can see what we have before we decide on what restoration we need.We keep ordering recommended spark plugs and they all show up wrong. The plug is smaller than the threaded hole in the head. Has anyone else run into this and if so what plug do I need to get. The last one we ordered was a champion c7 and it was too small. Share this post Link to post Share on other sites
ol550 825 #2 Posted December 14, 2017 Do you still have the plug that came out of it? May have a helicoil that came out with the plug. 4 Share this post Link to post Share on other sites
gwest_ca-(File Mod) 10,444 #3 Posted December 14, 2017 Champion L-82c or L-85 in this operator manual for the OH-160. A quick search found 14mm threads with a 12.7MM (1/2") thread reach. Garry 2 Share this post Link to post Share on other sites
pfrederi 17,040 #4 Posted December 14, 2017 I have a feeling that the overhead valve OH-160 would use a different plug than the Flat Head HH160. I am wondering like ol550 about a helicoil that came out. 1 Share this post Link to post Share on other sites
Marfam 1 #5 Posted December 14, 2017 The original plug was missing. Im thinking about a spark plug adapter to take it to 18mm. NGK does make an 18 mm plug but for ease in the future I think an adapter may be the way to go. Share this post Link to post Share on other sites
pfrederi 17,040 #6 Posted December 14, 2017 (edited) I just measured a helicoil spark plug insert. It is just under 17MM OD Edit Their instruction have you drill out the old hole with 5/8" drill bit. If that fits on your hole I would try getting an insert and see if it threads in. Edited December 14, 2017 by pfrederi 2 Share this post Link to post Share on other sites
Howie 881 #7 Posted December 15, 2017 I've never seen one of those with bigger threads than the 14mm. I would check about the helicoil insert. Share this post Link to post Share on other sites
Marfam 1 #8 Posted December 15, 2017 We have determined that the head has been messed with. My concern now is that it doesn't appear that this head has ever been taken off. Going to pull the head and see about installing a timsert insert. 1 Share this post Link to post Share on other sites
Howie 881 #9 Posted December 16, 2017 I have heard that some people try to put those inserts in without removing head. To me that is not a good idea! Share this post Link to post Share on other sites