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B20-25 Water Pump Housing Bolts....Thread sealant, grease, torque specs?

SoCalAngler

Regular Contributor
Hello all--
I have a 2017 Yamaha F25LWTC and am preparing for a new water pump install. I will be installing a complete WP kit with new bolts. I asked questions in Yamaha forum but no answers yet. While I wait for some responses, I thought I'd inquire on my old stomping grounds here at Honda forum!!

my OEM Yamaha manual does not provide water pump bolt torque values. Not sure why. Called a Yamaha dealer and they could not answer this.

Also, the manual calls for Loctite 527 thread sealant to be used on WP bolts and many other bolts used on motor. Difficult to source this Loctite 572 and they want like $30 for a less than 2oz bottle!!!! Dealer didn't even know what 572 was....they thought it was thread locker...it is not...it is a thread sealant (see attached TDS).

NOTE: Over the years, after a wire brush cleaning, I use marine grease on bolt threads for most, if not all bolts on my marine engines.

Curious about comparable Honda motors.....

Does Honda OEM service manual provide guidance on sealant and torque values for these BF20-25hp models:

1. A thread sealant for water pump bolts?
2. Water pump bolts torque values?

Thanks!
 

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  • 572-EN.pdf
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Well, in the 20hp manual the four 6mm x 1.0 .x 90mm "washer bolts" that secure the impeller housing are torqued to 11n•m (9 lbs. ft.).
No sealer OR thread locker mentioned and I have never used any on the litterally hundreds of twins that I have worked on.

Although, the NEW bolts that come with a NEW replacement housing do have a green tinted substance applied to the threads by Honda. It's obviously not the Loc-Tite 272 because that is listed as being white in color in the attachment you sent.

The "green stuff" might be Honda's version of 272 but I would think that they would mention it even if for no other reason than to sell a few tubes.

As far as the 25hp, that's a completely different service manual and it's a 3 cylinder engine. I have never seen a 25 in person. I did look at buying a broken 30, which is the same "family" I believe but I passed on the deal so I just don't know.
 
Thanks jgmo-

Do you use marine grease on threads or do you go with a dry install?
I’m probably overthinking this, but I try to do things correctly the first time.

I contacted Permatex and they have a thread sealant that is a close match to Loctite 572; it is Permatex 59214. It’s available locally.

Wondering if I should try this or marine grease?
Since the manual is calling for a thread sealant, I’m leaning towards using the comparable Permatex 59214, even though it is not the precise Loctite 572 sealant called for.

Thoughts?
 
Well, I'm going to agree with you on this and go with the sealant. I learned my lesson about 45 years ago on an old Ford V-8 waterpump. It had two mounting bolts that went right into the water jacket in the block. Those bolts HAD to have sealant otherwise they would leak. Leak BADLY!

Because there was the pulley and accessory bracketing in the way, the two bolts couldn't be easily removed to add sealant. You practically needed to do the job twice to correct the mistake. GIANT PAIN! But that's how my young axx learned to do some research before diving in.

So, if the manual calls for it, I would use it until that information changed.

On the Honda twins though, nothing is directed to be put on the mounting bolt threads for either the impeller "cover" or the pump base (which Honda calls a housing). So, I don't use anything because I also learned, many moons ago, that applying "stuff" to bolt threads when it isn't called for is also a no-no that will bite hard too.

Applying "lubricants" to bolts will decrease the amount of torque required to put the bolt into tension because thread friction is reduced. This increases clamping force and could cause component warpage as well as bolt failure.

Applying thread lockers and many "anti-sieze" compounds usually INCREASES the amount of torque required to put a bolt in tension because they increase thread friction. This can result in the bolt not changing state and entering tension. If that occurs, the joint is likely not going to remain clamped and the bolt can loosen, back out or fracture.

I would just caution anyone using a "knock-off" repair manual that those publications are known for having errors and mis-information and you never know if you're getting accurate directions.

Just sayin'.
 
Oh, here's something else I've learned...

We have a really wonderful, old school hardware store called Hank's Hardware. I love the place! You can almost get pretty much anything you need at Hank's

But....I have learned that items with a shelf life, sometimes, don't seem to move real well there. Stuff like glue and, yes, Loc-Tite I usually get someplace else because I have found some items there are just past their prime and don't seem to work like they should.

Again,

Just sayin'
 
Test the hole for the bolts, see if it goes into an opening or a deadend? I use Hylomar Ultra Blue on bolts and gaskets and mostly tighten by feel and then check it with a torque wrench. On engine bolts going into a water jacket, I use a white thread sealer product, I forget what it’s called, but it’s available at engine builders and auto parts places. It about like a runny toothpaste but stiffens up once in place and stays that way. It’s not a silicone that turns into a rubbery solid.
 
jgmo:
I agree on using OEM manuals. I purchase them for all of the vehicles/toys I decide to work on myself. This Yamaha one I recently purchased was nearly $100, but worth it IMO.

The Permatex 59214 is pretty close to the Loctite 572, not an exact replacement, but appears to be chemically very close.
I can't see it not working, causing any damage, or leaking.
Thoughts on using this one?

NOTE: I've been to Hanks a few times and he does have quite a bit of stuff, especially wood trim molding. I wish it was a little closer to me!

NSDON:

Might the Permatex # be 59235? If so, it is the same as the Permatex 59214 (6ml), the one I am considering using, only the 59235 is the 50ml version.
 
Also, the lower end install calls for using Loctite 518 on lower end. It doesn't specifically show exactly where to place it other than at a point near rear section. Wondering if it spread around lower end housing where it mates to upper housing?

NOTES:

A= Yamalube marine grease
GM= Loctite 518 (gasket maker)
LT= Loctite 572 (thread sealant)
 

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