Mercury 40-HP: Remedy for very stiff steering

[Wesley8808]

I have a 2006 Mercury 40-HP outboard engine that had very stiff steering. I tried to have the pivot tube fixed, but an honest mechanic recommended against doing that because of the high cost associated with a repair. The honest mechanic said the [engine] power head had to come off, which might lead to more problems. The mechanic thought to purchase a new [or used engine pivot tube], if one could be found, would be cheaper than the repair costs.

I took to the internet [for advice on how to make a repair]. I found advice that [the cause of the stiff steering in my 2006 Mercury 40-HP outboard engine was due to] the grease [in the pivot tube] hardening over time. My remedy was as follows:

• remove the grease fittings on the pivot tube
• drill and tap a hole in the top of the pivot tube for a new grease fitting
• drill out the ball in a grease fitting and install the fitting into the new tapped hole
• attach a two-feet-long tube to the upper grease fitting (with the removed ball); the tube should be a friction fit over the grease fitting
• fill the two-foot-long tube with KROIL penetrating oil; let gravity move the oil into the pivot tube; allow several days for the oil to soak into the tube
• remove the two-feet-long tube;
• use a blow torch to heat the pivot tube; this may sound scary but it will not be [dangerous];
• watch the heated grease come out [of the pivot tube with significant speed, and]
• repeat the above steps three or four times.

Before using this procedure, to turn the steering wheel would take two hands and much effort. After using this procedure the steering wheel could be turned with one finger.

[RLSmith]

Intriguing approach. I assume the "pivot tube" is the swivel bracket aka steering bracket. My outboard would benefit from this procedure. Questions:

1. How did you know what depth to drill the hole for the new grease fitting without unintentionally drilling into the contained shaft?
2. What type of blowtorch?
3. Did heating the pivot tube with the blowtorch remove the paint? How did you restore the anti-corrosion coating?
4. Did "the heated grease come out of the pivot tube" at the holes for removed grease fittings, the seals at the top and bottom of the shaft, or both?

Thanks.

[Phil T]

The grease fitting referenced is likely for the engine tilt and not for the steering tube.

The correct approach is to remove the steering cable, clean the cable and tube of existing grease.

Reapply grease to the cable and reinstall.

Replace the port side steering tube nut with a Steersman Nut (includes grease fitting)

There are two sizes, 1" and 7/8" so check your engine. This is the 1" nut.
https://www.wholesalemarine.com/steersman-boat-steering-guard-1.html

Grease 2x per year.

See photo below.

Fig. 1.

FrozenSteeringPhotoRevised3.jpg (132.96 KiB) Viewed 2966 times

[jimh]

I do not think that Figure 1 shows any of the area of the engine problem with steering that is under discussion in this thread. My reading of the thread is the problem is in the engine mounting mechanism and the pivot tube therein. That is why the initial report of the problem mentions that the engine power head must be removed to effect a repair.

[Phil T]

The OP states the problem is steering.

It is the mechanic who recommends a repair that involves the pivot (side-to-side) tube.

The OP lists steps gleened from searching the internet.

I recommend the owner disconnect the steering arm nut (see figure 1) and move the engine manually to verify the source of the difficulty.

[jimh]

I recommend the owner disconnect the steering arm nut (see figure 1) and move the engine manually to verify the source of the difficulty.

Yes, that is the logical first step in order to determine which element of the system is the cause of the resistance to turning. But in this case, the initial article in this topic thread presumes the problem is in the engine, not in the remote steering system or actuator.

The basis to assume that the diagnosis of the problem was completely wrong from the start is not reasonable, as the remedy described seems to involve the pivot tube, not the tilt tube--that is unless the description is so inarticulate that the tilt tube is incorrectly identified as the "pivot tube." However, the description seems to fit with the pivot tube, as there would be no need to separate the power head from the engine mount to lubricate the tilt tube.

[MarkCz]

My 1987 70 HP Mercury outboard has grease zerks on both the tilt tube and the pivot tube.

[jimh]

My 1987 70 HP Mercury outboard has grease zerks on both the tilt tube and the pivot tube.

Having a grease fitting on the pivot tube is probably common. Regarding the grease in the pivot tube becoming solidified, most outboard engine maintenance instructions require annual inspection and addition of new grease, forcing out the old grease. The grease in the pivot tube only hardens and creates a problem if the owner of the outboard engine neglected to follow the manufacturer's recommended maintenance interval for greasing the pivot tube for a decade or two of ownership.

[Jefecinco]

Using a hand held grease gun it should be possible to pump some solvent through the pivot tube zerk fitting to facilitate future lubrication.

[Wesley8808]

The method I used [to remedy the stiff steering] was on the vertical pivot tube, not the horizontal [tilt] tube that accepts the steering actuator. I did undo [the drag link between the steering actuator and the outboard engine tiller], and I greased the shaft [of the steering actuator]. But [that action] did not ease the steering at all.

I bought this boat in 2019 from the original owner, who I don't think maintained this outboard engine properly. The engine is a 2006 Mercury that was kept outside in a saltwater environment. I have read a lot about these Mercury' engines having problems with grease hardening in the pivot tube. I found a couple of youtube channels that showed some techniques: here is one:

https://www.youtube.com/watch?v=dJpw9IJ9H1U

For drilling the top grease fitting hole, I took my time. When the drill penetrates through the outer tube will be clear. I started with a small bit and gradually got bigger.

I also removed the lower grease fitting on the pivot tube when I was heating the tube with the torch so the hardened grease had as many exit holes as possible when it expanded. I mostly concentrated the torch on the lower half of the pivot tube. I used this torch:

https://www.homedepot.com/p/Bernzomatic-Bernzomatic-14-1-oz-Map-Pro-Hand-Torch-Fuel-Cylinder-332477/203226566

I did keep a spray bottle of water nearby as the penetrating oil will sometimes flash ignite.

I plan on repeating this procedure again soon, when I will take some pictures and record the technique.

Once I evacuated a good amount of hardened grease, I reinstalled the zerk fittings and greased the pivot tube.

Heating the pivot tube and watching the grease come out was oddly satisfying. I never let the pivot tube get red hot; I just applied constant heat moving across the tube to heat the grease on the inside.

I hope this helps readers.

[jimh]

'8808--thank you for the follow up and further clarifications on the procedure you used to remedy very stiff steering in your Mercury 40-HP engine due to the grease in the pivot tube having become hardened.