13
Dec
11

Beyond the Sea…horse!: Outboard motor restoration step by step…Day Two!

Painting using good quality paint can really make a final product stand out.  Peter McDowell explains the issues with using spray paint, which never really gets hard, on any product that will see hard service and or exposure to fuel.  You can read more on his website at North York Marine.  Peter also sells paint that is painstakingly matched to the original colors of our vintage outboards.  He’s a helluva nice guy, and very knowledgeable.

The main issue in painting a motor is preparation!!!  ALL parts must be totally free of all grease and grime, fuel, oil, and dirt.  To do this I use various stiff and soft bristle brushes and generic parts washer to get loose debris off each part after dis-assembly of the motor.

The old saying is "Cleanliness is next to Godliness!" "Tis true in this case. All parts must be degreased completely BEFORE using blasting media to get rid of paint.

Low grade lacquer thinner is used  to clean off the crud that is very stubborn or caked on.  Be sure to get up into nooks-n-cranies.  There are a lot of them on these old outboards.

For final prepping of parts, a clean bowl and clean lacquer thinner is used. I get my lacquer thinner in 5 gallon pails from the paint supply house.

Using a brush and lacquer thinner a final degreasing is underway. All grease must be removed before blasting parts to remove paint. Failure to do so will result in the blasting media just sticking in the remaining grease and potentially getting blown into the media and clogging your gun

In my post about Day One of this project, I suggested being into forensics is helpful.  This motor was suspected of being repainted somewhere along in it’s life.  It was painted a “correct” color of Johnson Sea-Horse Green which is darker than the 1946 to 1951 Sea-Mist Green.

Upon application of lacquer thinner to clean the main steering tube, this old Sea-Horses true colors were beginning to show.  The Sea-Horse green was wrinkling up and leaving behind the original color as seen below.

Here is where forensics that was mentioned in the Day One blog plays into the project. After application of lacquer thinner, the "second coat" of paint...Sea Horse Green is peeling like crazy...revealing this motors true colors.

The old dirty thinner used in the first cleaning can be reused to clean hardware used to put the motor back together. I use the original hardware always if possible.

After thoroughly cleaning ALL crud and filth off each part, blasting was done to rid each parts of it’s old paint and primer.  For this I use a generic blast cabinet and slag blasting media.  If a part is delicate, I may use soda-blasting as the media of choice.  The problem with soda-blasting is it works well, but the media is only able to be used once.  It also must be done outside of the shop.  The good thing is it is environmentally friendly in that it uses baking soda with is water soluble and thus easily disposed of with water.  Soda-blasting also does not dig into or etch the metal being blasted.  Additionally, unlike sand-blasting it does not heat, and potentially warp the metal being blasted.

All parts have been blasted in an inexpensive blast cabinet from Harbor Freight tools. Next it's time to prep for primer.

The power-head has also been cleaned and is stored in a tote until the cylinder block is finished being honed at the local marina.

Following paint removal, all parts must be cleaned again to remove dust and residue from the blast media.  Again, any impurities left behind will likely cause issues with primer adhering to the aluminum or could even cause paint to “fish-eye” when sprayed over those particles of impurities.  This will appear as an area that paint will spread out AROUND the particle or impurity.

Once the lacquer thinner has been used to clean all parts, they are hung up and allowed to air dry...or they can be blown dry with compressed air.

As always, when any motor is disassembled, mechanical issues arise.  A common issue found after a lower unit has been rebuilt is shown below.  A small dowel is inserted into a hole in the lower unit castings at the front and rear of the prop shaft.  The purpose is to “index” the bearing on the leading end of the prop shaft so it will not turn in the housing while under power, and the dowel at the rear (Prop-end) keeps the prop shaft seal housing from falling out of the lower unit.  Our front dowel has been pushed all the way down into the lower unit housing.  This must be removed and repaired as follows below.

Lousy photo...but in the area near the round edge you can see a little pin that is used to index the bearing on the prop shaft. This must be pulled out and replaced to keep the bearing from turning in the housing while under power.

Using a drill bit that is smaller than the dowel pin, drill a straight hole in the dead center of the dowel.

After drilling a small hole in the dowel, an easy-out removal tool, or even a sheet metal screw can be inserted in the hole to pull the dowel out of the housing.

The dowel is sufficently long enough that once it has been pulled out, it can be turned 180 degrees and re-inserted in the lower unit housing.

Here we see the dowel sticking out of the lower unit housing so it can now do the job it was intended to do by holding the bearings on the prop shaft in place.

Normally BEFORE priming and painting a lower unit, I would first rebuild and reassemble in to a sub-assembly.  However, upon further examination the weakest point of all lower units appears to be worn out.  The shift “sliding member” (OMC term) or “clutch dog” has had its ears worn by improper shifting.  Thus it will need replacement.  All OMC motors are designed to be “snapped” into gear!  “Easing” them into get creates premature wear of the clutch dog which engages the forward and reverse gears as shifted.

If in doubt...replace it. The clutch dog has seen its best days behind it.

The final preparation is to tape off, mask, or plug any holes that you don’t want paint to get into.  Despite primer and paint being only microns thick, it is enough thickness to complicate reassembly or create wear if clearances in drive shaft bearings are allowed to decreased even slightly.

To keep primer and paint out of the bronze bearings for the drive shaft, I use neoprene stoppers in the holes.

Any bearing surface within the steering tubes must be taped off to avoid being coated by primer or paint.

After a thorough cleaning with solvent, the parts are ready to be primed.  I use a PPG product from their Shop Line that is mixed with a primer hardener made specifically for this application.  Epoxy based primers are not of the self-etching type used on aluminum, but it does have some etching properties and seems to do well on a properly prepared aluminum surface.  It is touted to be good for most applications, and is commonly used in the automotive repair industry.

Primer used on most of my projects is an epoxy primer and hardener.

Per instructions, the primer is mixed 2 parts primer to 1 part hardener.

Using a mixing cup from the paint supply house makes mixing easy.

DP Epoxy Primers must be allowed to cataliyze with the hardener for 30 minutes after mixing.  This gives a bit of time for organizing parts to be sprayed in a logical sequence and any last minute cleaning that needs to be accomplished.

The clock is running!

During the 30 minutes we have waiting on the primer to do its thing, let’s discuss technique using an paint gun.  First and foremost…READ the instructions.  Each gun may vary.  The most basic features are a nozzle that allows a change in spray pattern by rotating the nozzle on the front of the gun.  There should be a knob to control with of the spray pattern, and finally a way to adjust the needle to control the amount of material/paint that can come out of the gun tip by pressing the trigger.

The gun! This is an inexpensive HVLP gun from Harbor Freight tools.

The business end of the gun! This nozzle can be turned 360 degrees to adjust the horizontal and vertical pattern of the spray gun.

This knob rotates to change the width of the pattern being delievered from the gun to the target.

This knob acts as a stop for the needle. Backing it out allows much more paint to flow from the nozzle, screwing it in restricts flow. There is also a stop nut that keeps the stop-nut from adjusting on its own.

Get used to this view! This is the disassembled gun. L to R: Gun, paint cup, needle, filter, nozzle, and needle stop nut.

So that is the basics of the HVLP gun.  This is a gun designed to put maximum material where it is supposed to go…on the part being painted.  This makes for less waste and better use of material than older styled paint guns.

After the clock has ticked off 30 minutes, we're ready to shoot the parts.

I use a stand for painting the underside of parts, then hang them to complete the job.

With parts hanging, primer is sprayed using and HVLP spray gun. Requires little air, and delivers plenty of material. Make sure you use no more pressure than needed...usually in the 20 to 40 psi range.

All these parts are now primed. Make sure all sides are covered with primer for paint to adhere properly.

Since I have some excess primer, I decided to prime so other parts that were prepped previously for other projects.

Okay, so now all the pieces and parts of the motor that need to be primed…are…well…primed!  What’s left?  Not much.  This primer requires you to paint the with the color coat within three hours to three days.  That is a pretty nice window of opportunity.  However, if your window slams shut, you will need to scuff-sand all surfaces to be painted with some 800 or 1000 grit wet dry sand paper or better yet a scotch-brite pad.

So that is it for Day 2!  Next we will paint the first color coat.  No doubt there will be the inevitable touch up and repair of a sag, drip or run!  So this is where the “artistry” will come in…along with patience, finesse, and a light touch!

All this work took 3.5 hours, so we now have about 7 hrs in our motor.

Hope you’ll join us for the next edition here:  Beyond the Sea…horse!:  Outboard motor restoration step by step…Day Three!

Greg


3 Responses to “Beyond the Sea…horse!: Outboard motor restoration step by step…Day Two!”


  1. 1 Pete Economos
    December 13, 2011 at 7:36 pm

    Greetings Greg,
    I talked to you via telephone a bit ago about the Aluma Craft that you had for sale but I missed out because some lucky person saw it and had to have it.
    I am sure he will be happy with it as well.
    I really didn’t connect the dots and realize who I was actually talking to.
    You were lucky because I would have probably picked you brain for longer than you may have wanted!
    I had previously commented on your restoration of your 1956 Johnson Javelin. (I located the “Javelin” scripts that I needed.)
    It was inspiring and helped push me “off the fence” with my restoration of the same item.
    Thanks again.
    You are really helping all of us “quiet restorers/enthusiasts” out there and you should be aware of that and thanked!
    It was a pleasure to talk to you and I look forward to your articles.
    Just another Thanks from me, Pete

    • 2 conductorjonz
      December 13, 2011 at 9:07 pm

      Thanks Pete!

      Good to hear my mistake may help others! I enjoy working on old things. Boats, outboards, radios, tv’s, and anything else that comes along. Nice to see these things survive!

      Take care!

      Greg


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