Stripped spark plug hole on chainsaw

[pbm]

The spark plug (Champion DJ8J) on my 35+ year old McCullough 3.7ci chain saw won't tighten down because I apparently stripped the threads. I have never used a Helicoil or Timesert and I'm looking for suggestions on how to fix this beast of a saw?
The DJ8J plug has 14mm thread but there are very few of them. I use this saw so infrequently that I usually need a blast of 'starting fluid' to get her running so the plug is removed to spray it in....thus I dont see JBWeld as an option. Do any of you have suggestions? Thanks in advance.

 

[thastinger]

It is easy to get the cylinder head off of a chainsaw. I would remove the head, weld it up and rethread it.

 

[thastinger]

or Ebay might have a used head, I sometimes have luck in finding older used parts on there.

 

[demarpaint]

I'd look for a used head as already mentioned.

 

[wpod]

Helicoil or Timserts are easy to use.

 

[Escape08]

Try inserting a washer, see if it works

 

[jeepman3071]

Helicoil or Timserts are easy to use.

+1

This would be my suggestion, otherwise remove the cylinder head which is more work. You shouldn't need to remove the spark plug every time you start the saw. Instead just pull the cover off, spray some fluid in the air filter/carburetor and put the cover back on then start the saw.

 

[Chris142]

Put a helicoil or timesert in. super easy to do.

 

[mk378]

Do those work on a taper seal plug? It seems like drilling out the hole would interfere with the area where the taper seals.

 

[DriveHard]

If you were closer, I would sell you my saw cheap, as I moved and no longer have use for it.

Time = money...

While there are many cases it makes sense to repair things, I am learning the older I get it is often more financially efficient to purchase new or used in place of my time and energy repairing something smaller like a chainsaw.

Things to think about...

-will I learn anything by making this repair? (learning trumps time and money IMHO)
-how close will the money I spend for the repair come to replacing the item...when the new item should in theory have a much longer overall life
-what other problems will I cause attempting the repair? Stripped threads, broken bolts, cracked tubes...etc.

 

[DriveHard]

Try inserting a washer, see if it works

I would say using a plug with a longer reach (risky), or machining the seat would have more of a chance. Every spark plug I have seen has threads that run all the way to the seat, so I don't see how less engagement could help this situation.

If you want a "CHEAP" solution, just coat the threads with JB weld, screw the plug in until just before you can feel the thread skip, and let it sit a week. I bet it will work until the plug fouls for the final time at which you can decide to replace the saw or head (which you would have to do anyways) at that time.

 

[Astro14]

Used head is simplest.

Time Sert is the best repair if you can’t find a used head, but it’ll cost as much as an entire used saw.

Helicoil is OK, if you’re not going to be removing the plug often, which you said you are.

So, I would look for a used head, or take it to a small engine repair shop that already paid $100 for the Time-Sert kit, and will charge you a few bucks for an easy repair and the cost of one insert.

 

[pbm]

Thanks Guys....Lot's of good info/ideas here.

 

[nwjones18]

I used the helicoil kit that comes with the tap and everything on an old boat motor once with success. I was nervous every time I removed the plug after I had them in, but don't recall having any issues.

https://www.amazon.com/Heli-Coil-Helicoil-5334-14-Thread-Repair/dp/B0002SRF4O

 

[Tdbo]

Repairing the saw in a quality manner will cost more than it is worth.
Unless you have a sentimental attachment to the saw, you probably would be better off putting that money in either a good used saw, or a new one.

 

[Lubener]

I have an old (1973) small McCullough Mini Mac with the same problem, same spark plug.. I haven't dealt with mine since I have other saws. On mine, the head is part of the whole cylinder assembly . You may want to look on yours to prepare for that if you take it off the saw.

 

[97K15004WD]

McCullough has been out of business for over 25 years. Parts are probably going to be hard to find.

Helicoil or Time sert would be my go to.

 

[97prizm]

Used head is simplest.

Time Sert is the best repair if you can’t find a used head, but it’ll cost as much as an entire used saw.

Helicoil is OK, if you’re not going to be removing the plug often, which you said you are.

So, I would look for a used head, or take it to a small engine repair shop that already paid $100 for the Time-Sert kit, and will charge you a few bucks for an easy repair and the cost of one insert.

Yeah I went to several different repair places when my neon spark plug stripped. The time cert looked way better but was $1,000 vs $200 to helicoil.

 

[RooflessVW]

.

 

[Cujet]

Just an FYI, piston aircraft engines use Helicoils, new from the factory, for spark plug threads. It is a time honored way of ensuring integrity.

In this pic, you can see the Helicoil and the threads for the Helicoil. And I promise, that's a Helicoil, not an insert.