fdsinozich 1 #1 Posted April 29, 2011 My C120 Auto has a Tecumseh HH120-120180D. I changed the plug and now it loses power and rpm when put under a load. I put the old plug back in and no improvement. The only thing I have noticed is that the terminal on the plug wire ( where it goes on the plug ) is not round like on an automobile plug. It looks like it is only contacting one side of the top of the plug. Is that normal for this engine? Or do I need to look elsewhere for the loss of power? Thanks, Frank :D Share this post Link to post Share on other sites
puddlejumper 67 #2 Posted April 29, 2011 Was it losing power before you changed the plug ( that being the reason for the plug change) or did it start after the plug change. Share this post Link to post Share on other sites
fdsinozich 1 #3 Posted April 29, 2011 After the plug change. It was mowing fine, I just wanted to change the plug since I have only had the tractor a few weeks. Should have left well enough alone. Share this post Link to post Share on other sites
puddlejumper 67 #4 Posted April 29, 2011 Well thats odd since it does it with the old plug also now. Try running it after dark and see if maybe the plug wire is arcing to the block somewhere ( Bad coil wire and when you moved it it found a place to ground.) I would like to say the new plug is bad (luck of the draw) But since the old one is doing it also I think if it is not arcing I would still try another new plug Just for sh@ts and giggles if nothing else you will have a plug for next years tuneup. Share this post Link to post Share on other sites
puddlejumper 67 #5 Posted April 29, 2011 By some chance did you pull the spark plug boot down some on the coil wire. You might try to push the wire into the boot and see if a ring appears that actually goes around the spark plug. I know this sounds simple but you did say something was off in the way the connection is made. :thumbs: Share this post Link to post Share on other sites
fdsinozich 1 #6 Posted April 30, 2011 :thumbs: Turns out it wasn't the plug or plug wire, I changed both. I forgot that I had tried to free up the throttle movement and inadvertently tightened the governor clamp too much. I loosened that and problem solved. What a moron!!! Thanks for the responses. Frank Share this post Link to post Share on other sites