Engine Mounting Bolt Torque

Optimizing the performance of Boston Whaler boats
jwaters58
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Joined: Tue Jun 18, 2019 7:35 am

Engine Mounting Bolt Torque

Postby jwaters58 » Fri Jan 24, 2020 8:07 am

When the engine mounting height is changed, what is the proper torque on the engine mounting bolts?

I have a 17 Outrage II with a Suzuki DF140.

biggiefl
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Re: Engine Mounting Bolt Torque

Postby biggiefl » Fri Jan 24, 2020 9:15 am

Snug. Do not over tighten, just tight. I have never torqued an engine bolt. I also like the metal "spreader" bars on Whalers which look nice and spread the load better.
On my 24th Whaler. Currently in the stable: 86 18' Outrage, 81 13' Sport(original owner), 87 11' Sport, 69 Squall(for sale cheap).

jimh
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Re: Engine Mounting Bolt Torque

Postby jimh » Fri Jan 24, 2020 9:26 am

The engine mounting nuts are usually elastic stop nuts. Too much tightening can begin to compress the transom. You are working steel against fiberglass with foam and wood interior. Don't crush the transom fiberglass.

NLA01
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Re: Engine Mounting Bolt Torque

Postby NLA01 » Fri Jan 24, 2020 10:21 pm

Do not over tighten. Over-tightened bolts will crack an outboard aluminum bracket. Use of 3M-brand or any brand sealant on bolt threads will change the torque and can cause you to over tighten by lubricating the threads. Torque will change with bolt thread count, too. Fine thread bolts will tighten tighter with the same torque as course thread bolts and nuts.

I am not sure about elastic stop nuts. I know [nuts] will gall out and lock up.

I have read 35 to 50-foot-pounds.

Archie

jimh
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Re: Engine Mounting Bolt Torque

Postby jimh » Sat Jan 25, 2020 7:47 am

Read the installation instructions for your outboard engine to find the recommended torque setting from the manufacturer for your particular engine mounting bolts.

Evinrude's literature for their legacy E-TEC V6 225-HP engine states:

MOUNTING BOLT INSTALLATION

IMPORTANT: Use a marine sealant rated for
above or below waterline use. RTV silicone is not
approved for below waterline use. Polyurethane
sealants are not easily removed and may damage
outboard or boat mounting surfaces.

Apply marine sealer under hex heads of bolts, on
the mounting plates, and to the bolt shanks...

Tighten nuts and bolts
to a torque of 40 ft. lbs


Source: Evinrude E-TEC Installation and Predelivery

Re thread galling: if stainless steel mounting hardware is used, an anti-galling compound may be necessary. See the FAQ for more advice:

http://continuouswave.com/whaler/reference/FAQ/#Q8

jwaters58
Posts: 18
Joined: Tue Jun 18, 2019 7:35 am

Re: Engine Mounting Bolt Torque

Postby jwaters58 » Sun Jan 26, 2020 5:30 pm

Thanks for the replies.