Engine clean up time

Don't you have a lot of electronic connections, switches, breaker etc down there? I don't think you want to prep the ER like you are washing a car. I would suspect a lot of it is close hand work with a lot of rags.... I never done it except as annual up keep.

So far so good with shop towels and spray cleaners on a regular basis.

And toothbrush, rag on a screwdriver tip, etc.

Tin foil wraps around hoses, sometimes slightly easier than masking with tape...

-Chris

Simple Green is your friend, non-toxic, safe to be around and will actually degrease. Now you just have to be careful what your bilge pumps discharge, nothing that will create a sheen.

Been thinking about doing some painting myself. Just did a quick search on primer. Came up with information that self etching primer should only be used on unpainted metal. Use an epoxy primer on metal that is painted... ?

I have had good luck with Simple Green products over the years, they tend to be more environmentally friendly than others.

They also have a heavy duty purple product:https://simplegreen.com/products/pro-hd-cleaner-degreaser/

When you're painting enamels like Boomer said he's using than all you need to do is complete a very good degreasing /washdown and the alkali in the enamel will self etch and adhere to the existing base enamel that your spraying or brushing over. The enamels are relatively soft and will yellow over time and will degrade. If you have the time and inclination than degrease and washdown the motor, Tape off with good 3-M tapes and masking paper / alum foil where needed and then use a non sanding epoxy primer (any brand, doesn't matter as long as its epoxy) on the entire engine than you'll be able to topcoat with any polyurethane of your choice like Awl-Grip, Alexseal, Jotun etc. Much harder coating , non yellowing with exception of turbos etc , An all around superior coating with less degradation maint. & shine wise. Two part polyurethanes are now being manufactured in "rattle cans" that have advanced spray nozzles that provide a professional job so the need for conventional HVLP rigs and difficult mixing calculations are alleviated .

Make sure to get a paint suit and the correct respirator and provide good ventilation.

Z-Spar 100 -G gloss White will darn near stick to a puddle of lube oil. Might have a fish eye or two but it'll stick! Prime any bare metal and convert any rust with Ospho. Wipe down large components and parts with a prep solvent prior to painting. Petit , Z-spar or any auto paint store make / stock a good generic prepsolve for this .

It will come in quarts and gallons. Use a "Pre-valve " for spraying. I don't recommend attempting to brush coat an engine. Pre valves are very good for getting into tight corners and will give you professional results on any surface. A large Pre -valve bottle and charged atomizer will cost around ten dollars and two should be enough for one engine and gear. You will use a gallon between both motors, gears ,mounts and engine beds in my experience.

The Caterpillar spray cans are cheap, coverage is excellent and the finish comes out very nice. It's what I use many times on various brands of engines.

This sounds good...they have white ? Or is it just Cat yellow? Will it stand up to the DD exhaust manifold heat for a few years?

Cat has White . Water cooled or jacketed DD manifolds yes, otherwise its barbecue grill paint for manifolds.