1964 Merc 650 cylinder block-stripped spark plug thread

[LunaStarcraftJupiter]

Previous owner mis-aligned/overtightened one of the spark plugs at some point. I'm not able to replace that plug because it damaged the threads on the cylinder block and the spark plug in there now is the only one that will sit properly. Is it possible to fix this without replacing the whole block?

 

[Johnson110]

I have a 115 hp mercury 4 cylinder, The second cylinder had a stripped spark hole from previous owner. I used a time cert, its thread that you screw into the stripped spark plug hole and you use the thread locking compound on the threads before you CAREFULLY thread the cert into the block. Now the one I used, mfgr: gearwrench p/n: 2128d size: 1/2 long, 14mm spark plug rethreader. Maybe one on the guys on the forum can tell you if this the correct size for your motor.

 

[racerone]

A careful repair with a " helicoil " insert works as well.----Replacement block might not be hard to find.----Your location ?

 

[LunaStarcraftJupiter]

I have a 115 hp mercury 4 cylinder, The second cylinder had a stripped spark hole from previous owner. I used a time cert, its thread that you screw into the stripped spark plug hole and you use the thread locking compound on the threads before you CAREFULLY thread the cert into the block. Now the one I used, mfgr: gearwrench p/n: 2128d size: 1/2 long, 14mm spark plug rethreader. Maybe one on the guys on the forum can tell you if this the correct size for your motor.

Thanks! I will look into the time sert. Cheers

 

[LunaStarcraftJupiter]

A careful repair with a " helicoil " insert works as well.----Replacement block might not be hard to find.----Your location ?

Yes I thought about a helicoil. Is it necessary to remove the block to do the repair? I did a quick search in the area for a new block and don't see anything. I'm in New York in the Catskills area.

 

[racerone]

The repair can be done without removing the block.------Just use grease on the tools to keep chips from entering the cylinder.

 

[Johnson110]

Curious to know how you,
if you fixed the spark plug thread?

 

[LunaStarcraftJupiter]

Curious to know how you,
if you fixed the spark plug thread?

I haven't gotten around to it yet but I'm planning on doing it in the next few weeks. I'll update here.