Stripped bolt hole

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Jay415
Posts: 433
8
Location: Long Island, NY

Stripped bolt hole

Post by Jay415 »

Ok this problem isn't for my tin boat but I received some outstanding help for my other 2 motors on this site. I just recently purchased a 2002 20' center console Proline with a 150HP Mercury Outboard for saltwater use. I was changing the thermostats today which don't look like they've ever been changed. Lots of saltwater corrosion and one of the bolts will not tighten now. I think the hole's threads pulled out with the bolt when I removed it. When I put it back it just got slightly snug then broke free, now it won't tighten at all. #-o What's the best fix for this? Should I just have my Marine Mechanic handle it? I left him a message but he hasn't gotten back to me yet (it's after hours) and I'm impatient! :lol: I won't attempt anything before I speak to him, but I just wanted to get some input from you motor guys.

sawmill
Posts: 207
7

Stripped bolt hole

Post by sawmill »

I would use a Helicoil. You drill the hole out and tap it with a special tap and screw a coil that looks like a spring into it and the inside of this has the correct threads for the bolt. You can buy a kit that includes the tap the tool for installing the coil and has some inserts in it. Maybe the marine place can do it cheaper as they probably already have the tap and tool for installing.

Talons
Posts: 155
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Stripped bolt hole

Post by Talons »

The bolt definitely stripped the threads, whether they there or not, don't matter.

You need to 'rethread the hole'. You do that with what the other gent said, a helicoil. Remember that most outboards are made out of POT metal. This is a cheap aluminum mix and overtightening bolts happens all the time. That is why you're best bet when tighting the bolt is 'under-tighten' then go back and 'bump it' up. Never overtorque. Now, this is great because it is after the fact and does not help you.

BUT, the mechanic guy probably already has ALL of the items he will need to take care of this. As a matter of fact, he should be able to actually fix it and get you ready to go in less than an hour if he is not busy, or you slip him a $20. :D

Good Luck,
Talons
If you are not having FUN, you're doing it WRONG!!!

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Jay415
Posts: 433
8
Location: Long Island, NY

Stripped bolt hole

Post by Jay415 »

Cool thanks! I just researched them online. Looks like exactly what I need.

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Jay415
Posts: 433
8
Location: Long Island, NY

Stripped bolt hole

Post by Jay415 »

Talons wrote:The bolt definitely stripped the threads, whether they there or not, don't matter.

You need to 'rethread the hole'. You do that with what the other gent said, a helicoil. Remember that most outboards are made out of POT metal. This is a cheap aluminum mix and overtightening bolts happens all the time. That is why you're best bet when tighting the bolt is 'under-tighten' then go back and 'bump it' up. Never overtorque. Now, this is great because it is after the fact and does not help you.

BUT, the mechanic guy probably already has ALL of the items he will need to take care of this. As a matter of fact, he should be able to actually fix it and get you ready to go in less than an hour if he is not busy, or you slip him a $20. :D

Good Luck,
Talons
I'm sure the bolt stripped the threads I don't deny that. But I definitely didn't over tighten. It never tightened more than very slightly snug. The saltwater corrosion definitely eroded the threads.

Talons
Posts: 155
7

Stripped bolt hole

Post by Talons »

Please don't take offense, none was intended.

Well, that sucks. But, hey, there it is. I had a '66 Mercury 9.9 Outboard that I never could get fixed and it had a stripped bolt hole around the water cooling cover. No one would touch it because it was so old. It was not corroded, it was force stripped.

I got it as part of a package deal, though, so it was actually the spare engine.

Talons
If you are not having FUN, you're doing it WRONG!!!

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Jay415
Posts: 433
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Location: Long Island, NY

Stripped bolt hole

Post by Jay415 »

No offense taken I was just saying that it was inevitable. I should have just had my mechanic do it, then he would have had the problem not me! :lol: instead now he has to fix my problem. He made some adjustments for me today and said "you should change those thermostats, its only 2 bolts on each, shouldn't take you long" :lol: I'm hoping he can fix it for me and if so, do it tomorrow. I was planning on getting out Sunday. I really don't want saltwater leaking all over the inside of my motor.

JMichael
Posts: 2926
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Location: Northeast Arkansas

Stripped bolt hole

Post by JMichael »

I'm not a big fan of helicoils myself. They are notorious for coming back out with the bolt the next time you remove the bolt. A helicoil is nothing more than a coiled piece of wire that you are attempting to wedge between the bolt and whatever the bolt needs to grip to. Then you have to break off the little tang, and hope it doesn't fall down inside your engine. IMO a Time-Sert, Big-Sert, E-Z Lok, or one of the other solid piece repair systems is a better bet. Advantages of a repair like Time-Sert is that it is a solid piece of metal that actually screws in to the new threads. It has a positive locking method to keep it where you put it, you can get them in metric or standard, and you can get them in aluminum, stainless, or carbon steel. It may cost a little more by the time you buy the installation tools/kit, but it's worth it when you want the repair to be a permanent fix and as good or stronger than the original threads.

https://www.timesert.com/html/faq.html#3

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Jay415
Posts: 433
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Location: Long Island, NY

Stripped bolt hole

Post by Jay415 »

Cool I'll look into that as well. As of now I'm gonna try the simplest fix. I just measured the hole depth and it is about 3/8"-1/2" deeper than the bolt. Hopefully it is threaded all the way down. Gonna try a slightly longer bolt.

User avatar
Jay415
Posts: 433
8
Location: Long Island, NY

Stripped bolt hole

Post by Jay415 »

The longer bolt worked. Now I just have to find a stainless steel flange bolt the right size. I tested with a zinc flange bolt, since that's all I could find. That won't lay long is saltwater!

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