stripped lower unit bolts how to fix?

gazza2007au · Nov 19, 2010

i have a evinrude 50hp 1971 model the two front lower unit bolts have been stripped how should these be fixed if i need to use a tap does anyone know what size and thread type also what size bolt replacement?

F_R · Nov 19, 2010

Re: stripped lower unit bolts how to fix?

Heli-Coils will put the holes back to original dimensions, and you will use same bolts as originally specified.

It takes a fairly expensive, specialized kit to install them, so it might be better to just have a shop do it. Outboard shops can't live without them, so they know all about it.

gazza2007au · Nov 19, 2010

Re: stripped lower unit bolts how to fix?

i just looked up the helicoil videos on youtube they seem simple enough i will give it a try can someone tell me what size bolt and thread this motor has? a local shop will charge me $100-$120 for the two bolts

thanks for the reply F_R much appreciated

F_R · Nov 19, 2010

Re: stripped lower unit bolts how to fix?

gazza2007au said:
i just looked up the helicoil videos on youtube they seem simple enough i will give it a try can someone tell me what size bolt and thread this motor has? a local shop will charge me $100-$120 for the two bolts

thanks for the reply F_R much appreciated

Just for the bolts??? Or the whole job, or whole motor or what? Anyhow, the bolts are part number 305282 @ $5.96 each. Sorry, I don't have one to measure. http://shop.evinrude.com/

gazza2007au · Nov 19, 2010

Re: stripped lower unit bolts how to fix?

yeah the whole job would be around $100-$120 not including removing/installing lower unit

jeffersondodson561 · Nov 19, 2010

Re: stripped lower unit bolts how to fix?

One helicoil should not take more than 20 minutes to do and I am being leinient. If you want to do it your self the helicoil kit should only cost about 15 bucks and this includes the die. All of the information is on the back of the package (what drill size to use and such). Just know your thread size, being this is an OMC older model I am sure the threads are course.

F_R · Nov 20, 2010

Re: stripped lower unit bolts how to fix?

Remove one of the other bolts and you will have the thread size in your hand.

gazza2007au · Nov 20, 2010

Re: stripped lower unit bolts how to fix?

ok the helicoil option wont be available unless i take the whole boat to the shop and have the repairs done

for the time being i think im going to use this product only if i can properly torque down the bolts http://www.permatex.com/products/Au...r_systems/Permatex_Stripped_Thread_Repair.htm

wilde1j · Nov 20, 2010

Re: stripped lower unit bolts how to fix?

The big labor piece here is dropping and replacing the lower unit. Why not do that yourself, take the LU to a machine shop, etc. to have the Helicoils installed? Shouldn't cost very much done that way, certainly not 100 to $120.

oldcatamount · Nov 20, 2010

Re: stripped lower unit bolts how to fix?

I'd be a little careful using the Permatex. Remember, you may be the one that has to remove that lower unit next time and it won't be easy.

bailey · Nov 20, 2010

Re: stripped lower unit bolts how to fix?

Gazza I agree with you that looking at the video it looks like a piece of cake,BUT!! remember the thinness of the "lower unit walls" presents a whole different type of problems. You have to "nip" off the threads on the "heli coil" plus the little "tang" after you've installed it,easier said than done! (metal pieces entering your lower unit causes many problems later on). Do yourself a favor and to a search on this site, this helicoil, lower unit problem was brought up a few weeks ago.
Bailey

bailey · Nov 20, 2010

Re: stripped lower unit bolts how to fix?

Gazza may I apoligize (spell) I thought it was the drain hole screw (a senior moment)!
Bailey (I was referring to "RodBolt" reply of Nov. 2 Page 16 at 11:48 pm)

boobie · Nov 20, 2010

Re: stripped lower unit bolts how to fix?

Gazza, I'd try the Permatex repair. Haven't seen that one but it looks like it might work. I'm from the old school and still use heli-coils.

gpsguru · Nov 20, 2010

Re: stripped lower unit bolts how to fix?

Helicoils will be the strongest repair.............. in fact stronger than the original thread as the coil will also apply axial force as the bolt is tightened. This is a permanent repair and also used in the aircraft industry.

As has been said .......... about 15 - 20 bucks for the kit and about 15 minutes to do the job. The thread will be UNC.

I rebuild classic engines (mostly V8's) and often have the helicoil the cylinder head bolt holes in ali blocks ....... some of these are going up to 80ft/lbs torque.

stripped lower unit bolts how to fix?

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