Engine layup afloat 6-9months

Tim Good

Tim Good

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We’re laying up our boat afloat in Brazil for up to 9 months. Would you:

A: leave battery connected and not flush the raw water circuit. Pay then marina to turn the engine over every month for a minute or two.

B: flush the engine through with fresh water + corrosion inhibitor, ensure battery is fully charged and disconnect the battery negative. Don’t turn it over for period of layup.

C: something else.

In each case say why you prefer you’re choice.

Update: Perkins M90 4.236 diesel engine in a sailing vessel
 
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Not sure what type of engine you have but if it’s petrol, I would go for option B.
I would also change the oil and filter and add fresh oil, run it for a couple of minutes to ensure the new oil coats everything internally. Remove the spark plugs, add a little bit of thin oil or fogging oil down the spark plugs holes, crank the engine for a couple of seconds so that the walls are coated and fit the plugs back. Top up the fuel and add the correct amount of a decent fuel stabiliser.
The other usual stuff that you would do to a boat when laying up for a long period is also a must, i.e, ventilation, moisture traps etc.
 
I would go for option B. Run it nice and hot the last time you use it. Make sure there's no salt left in the cooling system. Remove the impeller.

I've routinely left engines for six months laid up and never had a problem. I don't think nine months is fundamentally any different.

When recommissioning it, I like to pour a bit of fresh oil in at the top to coat the rockers etc, and then turn the engine over by hand if possible, or if you can't do that, a brief blip on the starter without letting it actually start.

There's no real point in running it periodically over the lay up period, IMO.
 
Flush through with decent Coolant / Fresh water mix .. as this will reduce salt residues as well as distribute the anti-corrosion additives in the coolant.
Close all valves once done to hold flushing medium ..

Disconnect battery ? If everything is turned off as well as the isolator switches .. why ??

No need to turn over engine IMHO. But at end of layup - turn engine by hand slowly (you only need a part rotation) to make sure all free before hitting starter.

Changiong oil and filters is not a bad idea at start of layupu .. to remove any acidity residing in the old engine oil.
 
There is some oil specifically for lay up on piston engined aircraft. Called inhibiting oil. It coats the internal surfaces. At putting back into service, drained and fresh oil put in + filter.
 
You might find that your battery has had it after being left for 9 months. Can you fix up some kind of trickle charger (solar?) Or get the yard to charge it from time to time?
 
Tim Good said:
We’re laying up our boat afloat in Brazil for up to 9 months ... B: flush the engine through with fresh water + corrosion inhibitor, ensure battery is fully charged and disconnect the battery negative. Don’t turn it over for period of layup ...
Click to expand...

Option B for me.

I own a Perkins 4236 and have done some of the following. Other advise is based on my experience of cold layup of drillings rigs in humid environments: -
  1. Change oil and filters.
  2. Remove air filter if it has one. Spray some WD40 into the air inlet and then block off with a tape. This will keep any dampness out. Place air filter in a dry plastic bag.
  3. Daub some grease on the external linkages for gear leaver, stop cable and fuel cable. Years ago I found corrosion in Scottish winter environment. I think Brazil humidity needs to be considered.
  4. Lubricate the throttle cables at the back of the Morse control and the lever shaft with a light oil. On drilling rigs Fill the space between Morse lever and lever body with grease, to keep air out and stop any oxidisation of alloy / stainless shafts.
  5. Check that the back of the ignition switch is dry (if it is the standard Lucas switch and spray with WD40. Also spray inside key barrel with wD40 and then place tape over key slot. Same reason as point 3.
  6. If there's risk of condensation in the engine space due to environmental conditions, consider pulling wiring harness plugs and applying WD40 to the connections and then reassemble.
  7. If you have a sum tray, remove any sump tray water, and clean up any crud that has accumulated. Crud attracts moisture.
  8. Wipe down engine with a cleaner if it's dirty and then finally wipe over with a rag cover in WD40. This keeps condensation from accelerating any corrosion on the surface. if its clean don't bother, maybe just wipe over with WD40 assuming a high humidity environment.
  9. Treat fuel with an enzyme or biocide, topical fuel treatment.
  10. Tape off any fuel tank vents to keep bugs out.
  11. Consider preventing fuel theft by fitting and anti syphon cage in the top part of the deck diesel fill up flange , or removing the fuel hose at the tank top and blanking off somehow. Also blank off the bottom of the hose.
  12. If you have desiccant bags, place them in the back of the instrument panel. There is a type, not desiccant, that emits a moisture displacing vapour with anti corrosion properties. They last about a year or two. Desiccant bags once used no longer function, which could be quite fast in a humid country. Example Cortec VCI Inhibitors
Cortec have many products, which I have used for years on drilling rig layups. They are available on the consumer market. The products, greases, sprays, bags, pads all contain their product that emits the corrosion inhibiting vapour. They work well and I have left drilling rigs for a couple of years in tropical areas, come back and commission with no corrosion issues.

Good luck with your lay up.
 
Definitely B. Our boat was left with engine flushed through, batteries disconnected from each other and everything else, every winter for six months. But then Covid arrived and it was three years. On return the batteries showed 12.4 volts when reconnected, engine started after about 10 seconds of cranking, batteries were perfect for the remainder of the season.
 
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