Thread locker for outboard motor bolts?

Discussion in 'Boats, Blinds, & Gadgets Forum' started by fowlogic, Oct 29, 2017.

  1. fowlogic

    fowlogic Senior Refuge Member

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    I need to drop the lower unit on my Nissan(Tohatsu) 9.8 to change out the water pump impeller and maybe other related parts. What bolt thread lock(er) do I use on the lower unit gear case bolts and water pump bolts to reassemble. The service manual says ThreeBond 1401 for both. I can't find 1401, though 1401C is available. 1401C has a higher torque value to break it free. My '90 4hp Johnson manual says OMC Lock for the lower unit bolts, but OMC gasket seal for the pump mounting bolts. All I can find on-line is Loctite Blue. Can't find any outboard motor branded lock compound. Frustrated in Boise! Thanks!
     
  2. hatch

    hatch New Member

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    Honda/ Yamaha tech here.... do not put high strength thread locker on your bolts..Yamaha up to 350 hp use teflon sealer. Honda up to 250 hp use water proof grease. Three bond low strength would work fine..As noted above these are used to keep the threads from seizing not locking them in place. If you are worried just use a lock washer. hope that helps.
     
  3. Tailfeathers

    Tailfeathers Elite Refuge Member

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    I agree, its not the bolts coming loose but the corrosion that makes big trouble. I had a Merc outdrive I was trying to remove. Normally you undo all the nuts and the hydraulic rams and then simply lift and drop the lower unit a couple of times and the weight and shock pulls the unit off and the bolts let her slide. Not mine. I must have tried it a hundred times. Used tons of blaster, used heat and ice, even a small scissor jack to force it off. Rubber hammer, sledge hammer with a block of wood. Almost got to the dynamite and she finally let go a hair at a time. When it came off there was white and grey corrosion and salt that had jammed up the bolt holes big time. Grease is traditionally used on outboards, but I like the idea of thread locker. Grease gets old and can wash out. I like a soft flexible material filling the threads grooves so water and corrosion can't.
    Remember the strongest thread locker should only be used where needed and recommended with the proper torque. The strongest thread locker has to have heat applied to it to release. You don't want to have to heat and burn your paint on your outboard just to take off a not or bolt unless absolutely necessary. Goos luck....listen tho the professional advice of Hatch above my post.
     
  4. Tuleman

    Tuleman Elite Refuge Member

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    Agree; use only Low-Strength thread lock on those bolts.
     
  5. fowlogic

    fowlogic Senior Refuge Member

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    What low-strength locker do you guys recommend? I can't find the ThreeBond 1401. The 1401C version is available, but has a higher removal torque. Is Loctite Blue appropriate or still too strong? Thanks again!
     
  6. hatch

    hatch New Member

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    Again.......I work on hundreds of outboards a year.....most likely you are working with a 6 mm bolt with a 10 mm head....I use marine grease or liquid teflon and hand torque to 9ft lbs. forget the loctite........
     
  7. fowlogic

    fowlogic Senior Refuge Member

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  8. California Flyway

    California Flyway Elite Refuge Member

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    I too am far more worried about corrosion than bolts loosening. I put the silver Permatex never-seize on all bolts and nuts I remove on inboards or outboards.
     
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  9. fowlogic

    fowlogic Senior Refuge Member

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    I've got some Rectorseal Tru-Blu on order. It's a paste with PTFE. The label says 'with Teflon'. Suitable for most metals including aluminum and a number of plastics. Seems to have a minimum of nasty stuff in the ingredients. The SDS listed only one ingredient. It's at 50 ppm. I'm going to use it on the lower unit bolts and the water pump bolts.
     
  10. Tuleman

    Tuleman Elite Refuge Member

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    https://www.permatex.com/products/t...permatex-medium-strength-threadlocker-blue-2/

    Note; this also prevents corrosion, which is the primary reason for using it on your outboard. That it also prevents the fasteners from backing out is a bonus; something grease or anti-seize will not do.

    Here's another one that I've used in the past, with good success:
    https://www.vibra-tite.com/products...-threadmate/?gclid=CJmgvrXooNcCFZu1wAodV-4H9g
    ..it also claims to help with the corrosion issue.
     

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