Cross threaded a plug in block

[Manatee Mauler]

<2B402096>

Didnt realize the plug was cross threaded and messed up the threads in the block. If the head has to be replaced any rough idea what im looking at money wise? If my mechanic can rethread it how dependable would it be. I had the bright idea of switching out the plugs while i cleaned the compressor strainer. About 3/4 of the threads are chewed up a bit. The bottom left passenger side of the motor. Wont try this.again. Those plugs are a pain in the butt, especially compared to my old EFI.

[CatFan]

Machinist can install a helicoil insert on many engines. What do you have?

[Manatee Mauler]

250 pro xs. Im a midget and my fingers couldnt hold the plug even with the cowling off. So i put the plug in a socket and started it. The plug sits so far up in there and not being able to reach it even on a ladder sucked. Im 5'5 with short fat fingers...ah im pissed.

[Manatee Mauler]

Motor was one of the last made regarding two strokes, its only a few years old. Dont remember the exact date of production.

[CatFan]

250 pro xs. Im a midget and my fingers couldnt hold the plug even with the cowling off. So i put the plug in a socket and started it. The plug sits so far up in there and not being able to reach it even on a ladder sucked. Im 5'5 with short fat fingers...ah im pissed.

I’d ask Don and your mechanic what they think of boring it for a helicoil or trying a thread repair kit.

[Jtreed99]

Agreeing with Catfan, I believe Don and Joe will recommend a timesert http://www.timesert.com/html/sparkplug.html

[Bryanmc57]

For future reference, use a piece of 3/8" fuel line on the plug to thread it in. Makes it easier to feel what's happening and much harder to cross thread it.

[Mike1969flh]

Use a threaded insert. Type that you stake in place. Also use high strength loctite. Kits are readily available. Can be done with head in place by a competent mechanic but recommend head removal to eliminate shavings in cylinder.

[Woody b]

It should be an easy fix for a competent mechanic.

Next time, and anyone else, if you're having trouble starting spark plugs put a piece of vacuum hose on the plug to hold it while your starting it.

[JOE54]

Agreeing with Catfan, I believe Don and Joe will recommend a timesert http://www.timesert.com/html/sparkplug.html

they will work but only way i do it is pull head ,still better to replace cyl head my opinion

[Jtreed99]

they will work but only way i do it is pull head ,still better to replace cyl head my opinion

Thanks for that clarification Joe but I hope I never need the advice!

[EuropeanAM]

Didnt realize the plug was cross threaded and messed up the threads in the block. If the head has to be replaced any rough idea what im looking at money wise? If my mechanic can rethread it how dependable would it be. I had the bright idea of switching out the plugs while i cleaned the compressor strainer. About 3/4 of the threads are chewed up a bit. The bottom left passenger side of the motor. Wont try this.again. Those plugs are a pain in the butt, especially compared to my old EFI.

Please take a few moments to review the Announcements at the top of the Forum, and be sure to provide the Required Info (serial number) when posting. Thanks!

The head needs to be removed BEFORE ANY FURTHER ATTEMPTS ARE MADE. Do NOT attempt to chase the threads... any metal that gets into the cylinder may also end up in the Direct (air) injector... neither place is good!

If you plan to have this repaired, it should be done with a thread repair SLEEVE (not a helicoil). Properly done, the thread-repair sleeve is swaged and locked in place, resulting in a permanent repair.

New o-rings (4) and new head bolts (20) are required (per head). NEW heads are another option, of course.

And of course- it's ALWAYS best to remove the lower cowlings before attempting repairs such as this.

[Sun Fish]

Didnt realize the plug was cross threaded and messed up the threads in the block. If the head has to be replaced any rough idea what im looking at money wise? If my mechanic can rethread it how dependable would it be. I had the bright idea of switching out the plugs while i cleaned the compressor strainer. About 3/4 of the threads are chewed up a bit. The bottom left passenger side of the motor. Wont try this.again. Those plugs are a pain in the butt, especially compared to my old EFI.

Did same thing 1,000 parts and labor new port head by authorized dealer to not effect remaining protection plan.

[JOE54]

^^^^^

[Manatee Mauler]

Sorry Don. I thought i put serial in there but it was on another post. I was just pissed. Serial # 2b402096. Thanks and sorry about that.

[krindgen]

Next time, 12in piece of radiator hose to install the plugs by hand before torquing. Slip it over the plug and feed it into the hole. Same thing for removing the plugs after they are loosened up.

[EuropeanAM]

Next time, 12in piece of radiator hose to install the plugs by hand before torquing. Slip it over the plug and feed it into the hole. Same thing for removing the plugs after they are loosened up.

Kurt- I've tried and used several different types of hose, but at the moment I can't imagine what radiator hose is small enough to use on a spark plug. Any idea what size?

[fly by night]

They make a special tool to put on the end of the spark plug to start it softly, different lengths for different applications. I have about 3 of those. You can pick those up and some auto parts stores, work great. I use mine all the time. Don may have meant 5/16 or 3/8 inch gas line would work but the professional tools are superior.

[JOE54]

i use a piece of hose comes with remote oil tank when they are new its nice and plyable about 3in long and straight

[Manatee Mauler]

Mucked it up good mech says. Ordered new head. Much rather go this route
Plat warty untill 2024, dont want to void it. Back ordered till feb 3. Wont be fishing for two weeks it looks like.