1999 200hp optimax, seized spark plug

working on a 200 opti and have a seized spark plug. im a mechanic, and I know what its gonna take to fix it but has anyone else had a issue like this? is it a common thing for these motors?

The Bottom most Plug is stuck on my 3 cylinder 75hp Merc I found out when I went to change my plugs this week . I am not a mechanic and have no Idea how I will get it out of there. Could I get a few Ideas on how to get it out of there ? Sorry for Hijacking your thread.

oh god no, that’s what its all about… helping people…. usually if you decide to power through and keep removing the plug it will take the threads out of the head. basically the head should come off, take it to a engine machine shop and have the threads repaired and reinstall the head with a new gasket. sounds like a huge project buts its not to bad on a 2 stroke…. maybe a hundred bucks for the gasket and probably a couple hundred at the machine shop. only [censored] part is you will be without a boat for a bit….. think im gonna wait till the end of the season and take care of this one for my buddy…. its hard to be with out a boat the week after opener….. now of you have a bad plug that’s fowled you will have to do it asap!. if you need any more help let me know!

Thank you so much !

Before you rip up the threads on the head, have you tried heating the bottom of the plug with a torch?

Obviously, you have to be careful with this and start with just a little heat, being sure to let the plug cool completely BEFORE you put the socket to it as you never want to remove a hot spark plug.

I wouldn’t heat it as aggressively as a stuck bolt, but I’d be tempted to try just a little heat and see what happens. Given that the brute force technique is likely to tear up the threads anyway, is there anything to lose?

And yes, obviously you don’t want to heat it so much that you risk warping the head, or other damage like drawing the temper of the threads. But I’d still try this as I’ve freed up a lot of stuck bolts with a little heat, it does work.

Grouse

If in no hurry, douse that plug with penetrating oil several times a day for a few days, then take a torch and heat the spark plug only. Let cool and give it a try. In the future a small dab of anti seize on the threads will prevent this situation in the future. Good luck.