Why paint an engine?
Painting helps prevent rust and makes an engine look brand new.
Above: The 1958 Johnson Seahorse.
After sandblasting the next step in restoring the Seagull was to paint it. Before sandblasting the metal surface was smooth, but without any paint it was now a little more coarse, like emery paper. Dirt could easily stick to the metal, and if this happened I would have to sandblast it all over again to get the dirt off. Paint won’t bond to metal if there is any dirt in the way. I had to handle the parts with clean grease free hands to ensure that dirt wouldn’t get into the tiny grooves on the metal.
Painting can be tricky. If too much is applied it will run or drip and the finished result will not look very professional. When I painted the Viking (a past outboard project), I gave it one coat, and when I saw that some places didn’t have enough paint I sprayed it again before the paint had dried. This resulted in large globs of paint in various places and didn’t look very good at all. I had to resand it and repaint it which was very time consuming and quite frustrating. The proper way is to give the object several light coats instead of one thick coating.
Before painting, remove all the old paint. With a small engine, the best tool for the job is a sandblaster. Once the old paint is gone, prime the metal before painting or use rust paint (no primer necessary). Primer helps the paint stick to the metal. It is best to paint on a warm dry day; this will help the paint dry and bond to the metal. If there is too much humidity in the air you run the risk of the paint looking “sticky” or taking ages to dry. I like to use cans of spray paint because you avoid brush marks with spray paint. Make sure you have a large drop sheet or piece of plywood under your project before painting.
Above: Painting the float bowl.
Here’s website that offers some useful advice:
After painting it’s best to leave the paint to dry for at least a week. Once I left a motor to dry only for one day and the next day I tried to reassemble it. The paint scratched off almost immediately; when I tightened the nuts and bolts, the underside of the bolt would scrape paint off the surface. It was incredibly frustrating. If I had left it to dry for longer it wouldn’t have done this. The paint eventually dried but the finished result was (sadly) amateur looking.
Painting bolts and nuts can look nice, but I find that when they are being removed the ratchet bit can scrape paint off the nut or bolt. One solution is to buy new bolts and bypass painting them altogether. This also avoids the issue of having old nuts crack during reassembly.
Above: Don’t forget to clean the cap off when you’re done painting! Old paint will dry up and block the small opening on the nozzle.
To clear the cap of paint you turn the can downside and spray for a few seconds, until the paint no longer sprays out.
After painting I used PlastiKote engine enamel to seal the surface. This adds gloss and prevents dirt from sticking to the paint. It looks especially nice on gas tanks and flywheels. It also handy if you’re replacing engine decals as it will keep the gasoline from dissolving the decal.