Shaft lock .... anyone fixed a stripped thread before ?

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Well it had to happem sooner or later ....

My Johnson 3.3 on the back of my little weekender has a thumb-screw for locking the engine in ahead position ... well it stripped the thread today and started a chain of events that did not bode well for a day on the river ...

Anyway - the thread is stripped from the soft ally boss that sits round the shaft ... the thumbscrew etc. is fine. Now what to do ?? S'pose speak to friendly workshop - see if they can re-thread with larger size ....

Anyone else cured this problem ?
 
Either a larger thread or repair the original thread with a 'Helicoil' or similar thread insert. Most garages/engineers should have the kit to do either job. Thread inserts end up with a stronger thread in alloy than the original.

Last time I had to use a thread insert repair, I went to a motorcycle workshop.(They are used to seeing damaged threads in the soft alloy of m/cycle engines) It cost me a few pounds for the mechanic to put the thread insert in, in a matter of minutes.
 
Had a Helicoil fitted to myn Lambretta .... ally head prone to throwing plugs !!

I thought they were illegal for plugs now ??

The size of this bolt on outboard is small though .... do coils go that small ? Anyway - let's hope Soviet style Latvian workshops can do something !!
 
I will certainly be looking around for such ... only trouble is the location - it's not UK !!

Let's see what workshop says this week ...

Cheers
 
If he has no access to helicoils, but is a real aluminium craftsman, it may be possible for him to add a bit more metal into the hole, re-drill and re-tap. But I would check what his aluminium welding looks like first!
 
Eaten away ???? The engine is like new and its stripped thread not corrosion ....

/forums/images/graemlins/cool.gif
 
1) Drill out if enough metal surround, chemical bond new metal plug in , drill and tap to original thread
or
2) Use a coil
or
3) Drill out to next tapping size



After any of the three above be more careful in the future /forums/images/graemlins/wink.gif

Good luck
Brian
 
Be careful ... have you seen the crap ally they use ??

From new - it never really locked the outboard .. as its a small pressure pad that is working amongst the grease etc. If it had a small dimple hole to sit into to lock it - would be much better.

I've now found a service that should be able to do it ... descibed what I want - they said ... "Dah - niet problemo .... savodni - harosho ??"

I said "Dah ... prekrasna ... spaseba ...!
 
There are thread repair inserts on the market that are far superior to Helicoils (wire inserts). A Helicoil insert requires a relatively larger hole to be drilled for the insert. In some cases, especially on smaller threads in cast / pressed out fittings there might not be enough spare metal to drill an oversize hole.

For the life of me I can not remember the name of these alternatives to Helicoils. A quick Google reveals: -

http://www.tappex.co.uk/

The above (the Ensat) doesn't sound familiar to me and they do look quite chunky, but slim inserts are available.

Standard Helicoils here: -

http://www.engineering-supplies.com/cat/88/helicoil-v-coil-wire-inserts-taps-gauges-/
 
;920983 said:
Well it had to happem sooner or later ....

My Johnson 3.3 on the back of my little weekender has a thumb-screw for locking the engine in ahead position ... well it stripped the thread today and started a chain of events that did not bode well for a day on the river ...

Anyway - the thread is stripped from the soft ally boss that sits round the shaft ... the thumbscrew etc. is fine. Now what to do ?? S'pose speak to friendly workshop - see if they can re-thread with larger size ....

Anyone else cured this problem ?
Click to expand...

What size is the thread? We use M5 Helicoils for Morgan car accessories.
 
A Helicoil will sort it, but bear in mind that it is not a lock system - the handbook warns against overtightening and tells you it will break if you try to lock the steering!

Rob.
 
I'd think that since the thread was started nearly 6 years ago the OP has solved the problem by now..

No longer a forum member anyhow
 
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