stripped threads-help?

Scott Chinsota

Petty Officer 1st Class
Joined
Apr 18, 2011
Messages
216
I have a '71 50 hp evinrude "hydro electric shift" :facepalm: . of the the four bolts attaching the lower unit, one wont torque past ten ftlbs (stripped), another can only go about 30 ftlbs (nearly stripped). fortunately the're diagonally located and the fifth bolt, under the trim tab is ok as well. the lower unit wont fall off :eek: but...i would REALLY like to adress this issue...correctly...asap. any suggestions?
 

emoney

Commander
Joined
Jul 19, 2010
Messages
2,551
Re: stripped threads-help?

Best idea is to take it to a machine shop and have them all re-threaded. In the mean time, you can always use washers to help snug it up.
 

Sixmark

Master Chief Petty Officer
Joined
Jul 11, 2010
Messages
890
Re: stripped threads-help?

Best idea is to take it to a machine shop and have them all re-threaded. In the mean time, you can always use washers to help snug it up.

If a hole is stripped a washer is not going to help snug it up in any way, a washer merely distributes the working load limits of the bolt head over a larger surface area. It's not going to help the bolt bite on threads that are no longer there.

Get it fixed properly before running it anymore, when torque is placed on the assembly with missing bolts it can cause damage from everything being misaligned or even worse it can come apart and endanger you or someone else.

If you have any experience with Heli-coils that might be an option for you.
 

Bifflefan

Commander
Joined
May 27, 2009
Messages
2,933
Re: stripped threads-help?

You will have to pull the motor off the boat (unless your reall good at working upside down) and turn it over so you can get to holes. Get the proper size Heli-Coils and install them per their instructions and you should be good to go. This whould only take you a couple hours at most if you have installed them before.
Good Luck
 

wilde1j

Vice Admiral
Joined
Apr 15, 2002
Messages
5,964
Re: stripped threads-help?

If you'vre never installed a Helicoil before, have a machine shop do. It will be done correctly then.
 

Scott Chinsota

Petty Officer 1st Class
Joined
Apr 18, 2011
Messages
216
Re: stripped threads-help?

If you have any experience with Heli-coils that might be an option for you.

yes, been there before. wasn't sure they would hold....and for how long. considered having it tig welded and re-threaded...probably expensive. i'm re-stringering and re-flooring right now so i have a little time before she goes back in service.
 

Scott Chinsota

Petty Officer 1st Class
Joined
Apr 18, 2011
Messages
216
Re: stripped threads-help?

You will have to pull the motor off the boat (unless your reall good at working upside down) Good Luck
oh im quite the upside down mechanic...changed rod bearings on a couple car engines with the engines still in the car. by the way, not much fun but possible.
 

wifisher

Chief Petty Officer
Joined
Mar 9, 2011
Messages
578
Re: stripped threads-help?

If you don't trust the Heli coil, then you may try TIMESERTS threaded inserts http://www.timesert.com. These are, in my opinion, a better option than a Heli coil.

Helicoils can be used without oversizing the hole as much as threaded inserts. If material removal is not an issue, then yes, threaded inserts are a stronger option. Your link is to one supplier of them. Google "threaded insert" and you will find many different manufacturers and vendors.

Helicoils are the more popular and easier option between the two, and if installed properly, will last for a long time.
 

RZR2007

Petty Officer 2nd Class
Joined
Apr 6, 2011
Messages
137
Re: stripped threads-help?

You can repair it yourself, buy a helicoil kit it comes with everything you need, correct size drill bit, heli coil tap, install tool, and different lengths of coils. Keep the drill straight, usually the bit will follow the hole pretty good, it's not much bigger than the stripped hole you have now, Keep the tap straight! I would also recommend stainless heli coils....
 

boobie

Supreme Mariner
Joined
Nov 5, 2009
Messages
20,826
Re: stripped threads-help?

A helicoil thread is actually stronger than the orginial thread. OMC Cobra stern drives had Helicoils in them right out of the factory. I've used them for many yrs and and never had a prob with them. It just takes patience when installing.
 

Scott Chinsota

Petty Officer 1st Class
Joined
Apr 18, 2011
Messages
216
Re: stripped threads-help?

Thanks for the help guys, i wasnt sure they would hold and i didnt know they made a stainless steel version. the threaded insert option may come into play if the heli-coils fail down the road.

The confidence to do what i must comes from the assurance of others who already know how.
 

Sixmark

Master Chief Petty Officer
Joined
Jul 11, 2010
Messages
890
Re: stripped threads-help?

Oh we don't know how, we are all just guessing.......lol just kidding!!!!
 
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