Loose Engine Mount Nut

[Favunclerich]

I'd like to follow-up after having started this thread a couple of months ago. After I discovered this issue, I re-aligned the engine to the prop shaft. Then I used a regular length 24 mm combination wrench and applied as much torque as I could within the confines of the bilge to tighten the nuts. There is insufficient room for a conventional torque wrench and socket for some of the nuts. It would be difficult to engineer something capable of applying measured torque within the confines of the bilge. I did not use Locktite.

The results are good so far. I've put around 100 additional hours on Roam after re-tightening the nuts. The nuts are still tight and I can detect no damage to the engine, mounts or prop shaft. Three other owners of tugs with many hours have contacted me privately. All have done the same and all have had similarly good outcomes.

I plan to continue to monitor the nuts, but it seems that including this as a 250 hour maintenance check should keep this from reoccurring.

 

[Levitation]

Rich, I agree that putting a wrench on them now and then every couple hundred engine hours is sufficient. I don't have a clue as to the grade of stud/bolt used on our 25's. And I suspect given the geometry where the engine is mostly compressing the bolt/nuts by it's weight and only minor amounts of tension during vibration are involved that a low carbon material is likely adequate - I take back my previous comment on that. More likely the nut was under torqued either at the factory or during subsequent efforts at aligning the shaft. 70 to 80 foot pounds are likely to hold it. A trick I have used many times where getting a wrench on a nut/bolt is a real hassle is to give it a squirt of bright colored paint. Enamel is the best because of the thicker paint film. Tractor paint is usually enamel. Anyway, I digress - then if the nut starts backing out the paint will crack and be your indicator.

Where are you folks currently? Beans are starting to yellow here and we are working on a combine.

 

[Binare]

nail polish works well too and is easy to apply without a mess.

 

[knotflying]

nail polish works well too and is easy to apply without a mess.

Now that is a good reason for the wife to bring nail polish. A little mascara and some lipstick and you will also have the prettiest engine mount in the fleet!

 

[Binare]

nail polish works well too and is easy to apply without a mess.

Now that is a good reason for the wife to bring nail polish. A little mascara and some lipstick and you will also have the prettiest engine mount in the fleet!

Im my defense, most electricians that deal with fire alarms carry red nail polish 😉 To make it easier for anyone else to pirchase, its cheap as dirt and fits anywhere hehe.

 

[R Baker]

This is very serious sh.. ! The 6by ya nmar has limited access to the motor mounts. So how the torque specs where satisfied becomes a concern. If there is any concern from the factory on this subject it's time for them to weigh in...please.
I asked in an earlier posting ....was there a maintenance schedule for the 29. There was no response. This is subject that might be identified as requiring regular attention.

 

[LADY JANE]

R Baker, Yes. For now, Please Read (on this pg.2 etc.) Sep 9, good entry's by Levitation/etc.. BB+

 

[knotflying]

This is very serious sh.. ! The 6by ya nmar has limited access to the motor mounts. So how the torque specs where satisfied becomes a concern. If there is any concern from the factory on this subject it's time for them to weigh in...please.
I asked in an earlier posting ....was there a maintenance schedule for the 29. There was no response. This is subject that might be identified as requiring regular attention.

It is serious, but I think that as owners it is incumbent on us to check all connections on a regular basis. Boats are in the most hostile environment I can think of, saltwater, bouncing and then add towing on bumpy roads. Wires break and corrode, connections corrode, clamps loosen and bolts loosen. It is a fact of life. The engine manual has a maintenance schedule as does the transmission. After that I would say check all clamps, hoses, fittings nuts and bolts on a regular basis. Check all systems for proper operation. If you have flooded batteries, check the water level monthly.

 

[Levitation]

" .. .. .. it is incumbent on us to check all connections .. .. .."

Here, here!

 

[LADY JANE]

I was just looking at an engineering web site and found a vibration proof, heatproof, & waterproof locknut designed to retain torque/tightness. This tightness retaining nut is something Ranger Tug owners could get for their engine mounts, where other hardware securing systems just won't work. Not all engine mounts are the same. This locknut, designated as the "A4 Nut" is manufactured for "salt water marine use" @ http:\\www.Aerotight.com. It has a locking mechanism that retains final torque when tightened down past the last 2 nut threads.. BB+