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I have a MTD yard machine - 38 inch cut. My problem is I have a spark plug I cannot get out. Very likely it is cross threaded. I can get the sparkplug wrench on the plug and turn but it comes to a point where can't turn any further (Not turning the wrong way, lol) I can turn backwards to a certian point then it stops. Tried spraying with "blaster" to loosen up, left overnight, but still won't come out. Mower will start, should I let it run a little while then try to get plug or will this hurt engine?

I am truly a "shade tree mechanic" tear up more than I fix but I like to try. I appreciate these type of forums and willing to help any way I can.

Thanks

On what you are describing you can remedy it one of two ways. #1 you could keep fighting with the plug and if it is cross threaded, you could put a heli-coil in it (which I wouldn't recommend). #2 You could buy a new head for it and install the new head, which in turn would give you a fresh spark plug hole that isn't stripped. I would elect for the new head, that way it is less time consuming and it is done right.

I appreciate the reply. I agree a new head would be the way to go. Goint to give it one more try this eveing to get it out, if no luck off to the shop it goes.

In addition to the last post - the other thing I could suggest is to put the plug back in tight and if it doesn't show any signs of leakage and runs OK -- just keep using it that way until it is obvious that the plug is not firing properly. THEN see if you can find a new or used head with a good thread for the plug.
I've been told that Helicoils work fine, but don't have any personal experience with them.

God Luck !

I have had very good luck with Helicoils. The last one I bought was last fall and the kit was 40 dollars. You might want to do what BKBrown said tighten it and look for a used head which wouldn't cost much more then a helicoil kit. Or maybe you know someone with the kit already.

I'm with BKBrown on this one... Why replace the spark plug? I have generators, chain saws, trimmers and a couple gasoline mowers that have spark plugs that are Well Over 10 years in service never any problems...
Unless your local landfill is needing more stuff, don't change out working spark plugs...
When you Do change plugs always use anti-cease, and an inch-pound torque wrench ... :smile:KennyV

If sporty is anything like me if I have his spark plug problim to just leave it alone is something I could not do. If something isn't right on any of my equment I just have to fix it. Can't help myself. I just start thinking about it and before you konw it I am working on it.

Another "advanced" shadetree mechanic and sometimes perfectionist. I'm on the side of tighten it back up and run it, supressing the urge to fix it right and fix it now. BUT - I would use the time wisely to acquire a replacement head on your terms for when, not if you need to replace the head due to the spark plug failing.

I tried again this evening, I can turn the plug counter clockwise for several turns when it becomes so tight i cannot turn any. I can then turn back the other way till it tightens up that way. Need a way to put pressure and pull the plug out. Big screwdriver may work. Any suggestions?

Grass ala Mowed said:

Another "advanced" shadetree mechanic and sometimes perfectionist. I'm on the side of tighten it back up and run it, supressing the urge to fix it right anf fix it now. BUT - I would use the time wisely to acquire a replacement head on your terms for when, not if you need to replace the head due to the spark plug failing.

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Maybe a shadetree mechanic when I was just starting in this trade I would do any job in any location, perfectionist I do the job right. The only trade I have done in the last 60 years of my life is a mechanic and most of them as a truck mechanic so to pull a head off a small engine is a small job to me. As a matter of fact in my retirement years I find working on small engines enjoyable. Now to fix the striped spark plug.. I own a helicoil kit with new inserts, it would be less then a 1/2 job for me and when I was done it would be like new with no cost to me. My helicoil kit has payed for its self on its frist job. Now as I recall on this trend in a earler post I said to tighen the plug and run it till he could find a used head. And by the way mowing grass to me I HATE the job but one of then jobs I have to do and you will find most pople on this forum love it.

I put another reply, don't know what happened. I have another mower just like this one. My uncle and I bought at same time. My deck rusted, my uncle gave me his (had to mow his yard of course). If I have to how hard is it to remove one head and replace another. Is there a "sticky" for this. I can give motor type and size. Thanks

go to youtube and type in lawnmower engine head removal. or Briggs head removal. 9 bolts and accessories around head, new gasket torque to specs done.

Putting pressure on it might work. I would loosen it up as much as you can, then either pry it with a flat head while at the same time loosening it; or pull on it with vice grips while loosening it with a wrench. Not sure if this will work but might lead to something. Also I have the same mower and I had stripped the threads while putting a new spark plug in and the new spark plug won稚 tighten all the way but the old spark plug fits in still and works so I知 just going to stick with the old one since it痴 not a problem yet!

Finally got plug out. Little bigger ratchet and slow turning. The end of plug had broken off, not sure how. I removed head and found some shavings and cleaned up. Plug hole would definitely have to be helicoiled. I have the head off my other mower going to try first. Gasket looked good. Hoped to put back on and be back in business. In putting the casket back on, will it hold in place or do I need to use something else. Thanks

I like Copper Coat spray ... SCE Gaskets G1612 - SCE K&W Copper Coat Gasket Sealer - Overview - SummitRacing.com

Works great when reusing Head Gaskets... :smile:KennyV

Use Permatex Aviation sealant. Sold at any auto parts store in a small container. I have used it for the last 60 years on head gaskets.

Well guys, not so good. Decided to go with head from other mower. Took off, cleaned what carbon I could (wasn't to bad) and put back on. Started and seem to run okay. Tried to start 15 minutes later, would turn but not hit. Took off air filter, sprayed a little starter fluid in card (left air filter off) and tried to start, started right up, but, when I lifted cover of mower, oil was shooting into breather through what I think is an exhaust hose (goes to engine). Immediately turned off but oil had covered everything plus you can see oil in bottom of carb. Is this something I done or did something just break in motor. Either way looks like a rebuild, any idea on cost?