Corroded Mercury Outboard Tiller Arm

Repair or modification of Boston Whaler boats, their engines, trailers, and gear
bobct1
Posts: 3
Joined: Sun Mar 25, 2018 10:09 am

Corroded Mercury Outboard Tiller Arm

Postby bobct1 » Sun Mar 25, 2018 11:14 am

I am in the market for a boat for my family and have found a great looking 19-foot Montauk. I am not looking for a project, but don't mind a little bit of work. Everything looks good except for some excessive corrosion on the [engine tiller arm]. From what I've read online, this is common on Mercury outboard engines used in saltwater. It seems to be a fairly pricey fix. Not anything crazy--just a lot of labor.

I'm [giving links to] some pictures. Any advice would be greatly appreciated.

https://drive.google.com/open?id=1X7dxc ... hR5rp1II2j

https://drive.google.com/open?id=1-lyaP ... uQemK4dC0z

https://drive.google.com/open?id=1rQHbS ... hnSdbyp-jB

https://drive.google.com/open?id=1qWmUT ... zSjU5mj4Dg

jimh
Posts: 6915
Joined: Fri Oct 09, 2015 12:25 pm
Location: Michigan, Lower Peninsula
Contact:

Re: Corroded Mercury Outboard Tiller Arm

Postby jimh » Sun Mar 25, 2018 2:17 pm

The component of the unidentified Mercury outboard engine is usually called the tiller arm. The one shown is badly corroded. I would not assert that the tiller arm shown and its condition is typical of all Mercury outboard engines used in saltwater; that one looks abnormally rusted. Perhaps there was a defect in the original manufacture in which the protective paint and corrosion protection were not properly applied, or perhaps the protective paint surfaces were penetrated by some sort of impact, and the damage to the surface was not properly repaired, thus allowing corrosion to proceed to the extent it has.

Replacement is likely to be labor intensive. A great deal of disassembly is generally needed to get to that component and remove it.

You should look for some resource, perhaps something on-line and at no cost, that shows more details of the construction of that portion of the engine mount and steering tube. A good drawing of that section will give you an idea of what will be involved in the remedy of that badly rusted tiller arm. You should try to find the factory service manual--at least get a look at one if you can--and make a copy of the drawing for that section.

I don't know if there is a mechanical joint between the tiller arm and the steering tube. If they are one piece the repair can be even more difficult to perform.

A long-shot: get the engine identification number, contact Mercury customer service, and inquire if there are any remedies offered by Mercury to repair this problem. Sometimes there are "silent" warranty coverages for certain engines in certain production sequences when there was a known deficiency in their manufacture.

kwik_wurk
Posts: 95
Joined: Fri Oct 16, 2015 3:23 pm

Re: Corroded Mercury Outboard Tiller Arm

Postby kwik_wurk » Sun Mar 25, 2018 2:25 pm

The Mercury mid-range horsepower steering arms from the late 1990's to c2005 experience corrosion rates far higher than one would ever expect or want. I would call it a defect. However they don't seem to limit operation, they are just a pain to deal with if you have to.

Mine were all of similar condition, and I never replaced them. Functionally the steering arms where plenty robust, so a little (or a lot) rust was cosmetic. If the arm is any thinner in material than a large crescent wrench, I would be worried, but I have never seen one get like that.

This said I will will say the last picture (2377.jpg) does show the trim-tilt sensor as probably toast. While I have not dealt with all trim-tilt sensors, in theory that should be one assembly, BUT a bushing or collar part may need addressing if it's going to completely fail. (Generally speaking said bushing or collar should not affect the actual rigid mechanical connection--should be a retaining clip--but if it does and allows any play (of the trim tilt rod), eventually that will find its way down into the trim tilt seals.

There are two other parts that can corrode as well, depending on model and vintage:

The early steering tubes were not all entirely stainless steel; check engine serial number io determine if so. Or, just make sure it's not stiff and sticky; with that sort of corrosion on the tilt arm, you'll know if the steering tube is also suspect.

Also on earlier vintages the bottom-most connection from the midsection to the tilting bracket [is a concern]. Depending on the vintage there is an exposed but little stainless steel braided grounding wire that if lost or broken can lead to corrosion of the nut fasteners, which is a big pain. You'll see the remnants if the wire is broken. I never had to deal with the aftermath, but my mechanic advised if the nuts can't be pulled off, it's not a big deal because cutting the bolts and replacing the small affected bracket was actually not hard to do or expensive.

bobct1
Posts: 3
Joined: Sun Mar 25, 2018 10:09 am

Re: Corroded Mercury Outboard Tiller Arm

Postby bobct1 » Sun Mar 25, 2018 9:13 pm

Thanks for the info. I should have specified, this is on a 2007 Mercury 115-HP EFI FOURSTROKE on a 19-feet-long Montauk.

You are referring to it as an Outboard Tiller Arm but from the info that I am finding online, looks like it is called the Swivel Pin Assembly. The part that is rusted would be the Swivel Pin Arm. I suppose it could be the same as a Tiller Arm.

It would be the top part of #9 in this drawing:

https://www.marineengine.com/parts/merc ... eering-arm

That is most likely not the correct serial# range--just linked to it for illustration purposes.

I wouldn't mind purchasing the boat as long as the seller adjusts the price somewhat. I'll try calling around, but would anyone be able to ballpark the cost of the repair. What makes me nervous is that I don't think the motor was professionally maintained. I am pretty sure that the boat sat in the water for the three or four months for the summer and then taken out. I don't think that it was ever rinsed down during that time. I am also pretty sure that he just changed the engine and lower unit oil, and called that winterized. Not sure that the anodes were ever changed. Supposedly, the motor has less than 200 hours.

Considering that it was probably not properly maintained, this may turn out being more costly than I would like. Or due to the low hours, for the right price, is this something worth considering?

jimh
Posts: 6915
Joined: Fri Oct 09, 2015 12:25 pm
Location: Michigan, Lower Peninsula
Contact:

Re: Corroded Mercury Outboard Tiller Arm

Postby jimh » Mon Mar 26, 2018 8:25 am

Nice find with that on-line drawing. It looks like the tiller arm or steering arm is only sold as part of the "Swivel Pin Assembly" that is CALLOUT 9. That is clearly a bunch of components already assembled into one big part. And it looks like you'd have a lot of disassembly of the engine to get to it.

vze2gbs4
Posts: 124
Joined: Wed Mar 30, 2016 9:34 pm

Re: Corroded Mercury Outboard Tiller Arm

Postby vze2gbs4 » Tue Mar 27, 2018 12:36 am

Had many whalers with exact same problem. Motor looks almost mint but tiller arm so rusted its ridiculous. But piece is rock solid - rust is mostly surface and there is a remedy, First take long flat screwdriver and remove all rusted surface particles the best you can . Second get thin wire brush and try to clean as much surface dust as you can. And for the miracle remedy pls buy Rustoleum Rust Reformer ( Home depot ). Little white liquid bottle with a pic of a chair on the label. Tape cowling around the arm for liquid dripping and apply with long brush-2 coats at least. You will not believe your eyes when your rusted piece of iron becomes black again and this time wrapped in protective plastic film against future corrosion. i did this procedure many times and had zero problems after rust treatment and arm performed as it should .Use this little bottle on my trailer since there are many parts there that need protection.Also undercarriage of the car or anything cast iron that loves to attract rust due to salt presence .But use caution- liquid will turn metal to black color after treatment so it works best to parts that were originally black color coated from the beginning.
I may take a heat for this but I would have zero problems buying a whaler with rusted arm like this boat has .

That corrosion on tilt arm is another story-I would probably worry more about this -that looks like it may crumble any moment .

MarkCz
Posts: 26
Joined: Sat Jan 27, 2018 3:44 pm

Re: Corroded Mercury Outboard Tiller Arm

Postby MarkCz » Thu Mar 29, 2018 6:18 pm

I repaired a 1987 70 hp Mercury that I needed to replace the exhaust adapter plate gaskets and water tube seal. I had to remove the powerhead to get to those parts and If you do want to change the swivel tube you will need to pull the powerhead. Since yours is a 2007 I don't think yours will be that bad. For my 1987 I had to grind off bolt heads and remove quite a few bolts so rusty I could not get a wrench onto them. it took quite a few hours but my time was free so I just addressed one bolt at a time. If it were me I would chip off the biggest rust pieces and put a few coats of Miracle paint on the rusty tiller arm. Some guy who repairs Mercedes sells that stuff. I used it on a Toyota minivan a few years ago and its still protecting the rusted area very well.

jimh
Posts: 6915
Joined: Fri Oct 09, 2015 12:25 pm
Location: Michigan, Lower Peninsula
Contact:

Re: Corroded Mercury Outboard Tiller Arm

Postby jimh » Fri Mar 30, 2018 4:32 pm

A new topic introduced into this discussion of repairs has been moved to another forum for discussion.

jimh
Posts: 6915
Joined: Fri Oct 09, 2015 12:25 pm
Location: Michigan, Lower Peninsula
Contact:

Re: Corroded Mercury Outboard Tiller Arm

Postby jimh » Sat Mar 31, 2018 7:14 am

bobct1 wrote:I ...don't mind a little bit of work.


Based on the comments from others who have encountered and repaired a Mercury outboard engine with a corroded tiller arm that is part of the "Swivel Pin Assembly", it seems that as long as the rust and corrosion is just surface and cosmetic, "a little bit of work" may be able to remedy this problem.

But another point of view says the presence of all that corrosion--that could have been remedied with "a little bit of work"--tells me the present owner was neglectful and failed to take good care of this engine. The corrosion on the steering arm or tiller arm may be a visible manifestation of a general neglect for the engine.

bobct1
Posts: 3
Joined: Sun Mar 25, 2018 10:09 am

Re: Corroded Mercury Outboard Tiller Arm

Postby bobct1 » Sat Mar 31, 2018 10:38 am

Guys, thanks for the advice.

Based on some of the comments here and others online, I think I may pass on purchasing this one. The boat itself is in pretty good condition, but I think that the motor may have been neglected. It's an 07 and the owner never changed out the water pump. I don't think the zincs were touched. Not sure that the motor was ever professionally service.

In addition the the questions that I have on the motor itself... the water lines on the boat have also peeked my curiosity. Looks like the boat is listing to the port side. The water line is approx 2 inched higher on the port side. Not sure if this is just the way that it was tied off and due to the changing tides, or if it is a sign of a larger concern.

Thanks again for the advice.