Boat Engines etc - Maintenance and Repair

Winterising a Mercruiser 4.3 V6 MPI and Alpha One Gen2

by argonaut » 15 Oct 2016, 17:21

First off there is no absolute right or wrong way … there are logical approaches, and foibles, I list my approach.

After last run of the year I put the appropriate amount of Fuel Stabiliser in the tank. (Mercury Quickstor at 7ml per gal of petrol)
Then it has a full service – I feel it better to have engine sitting over winter on clean oil, new filters etc. Why leave engine sit for 5 months on all sorts of crud & acids in the sump and oil ways.

As part of service – leg comes off, new water pump impeller fitted as well as gaskets and full inspection of gimbal oil seal and the various parts of the Transom seal kit (30-803099T1) If anything is in doubt it is changed – but if it looks fine then it is left alone.
Engine has oil change, new oil & fuel filter, plugs inspected and changed if any corrosion – modern Mercruiser plugs do not need changing every year. Gearbox oil replaced.

Engine is run to normal operating temp, on muffs – then swapped to run in a barrel of anti-freeze mix.
With air intake cover removed, then electrical connector to fuel pump is unplugged – with a can of fogging spray at the ready … once engine starts faltering as fuel comes to the end - empty spray can into air intake …. It will usually stall engine once all is coated.
At this time engine is running in an anti-freeze mix … so all the inside of the block has been coated with anti-freeze. Then the block is fully drained down.
The alternator/water pump drive belt removed (to prevent deformation)

All linkages are then cleaned of any crud (not much usually) and all parts are greased with marine grease.
A step I take is then to spray Corrosion block (http://www.acf-50.co.uk/marine.htm) over electrical connectors on the engine, HT leads, battery connections & switch and in my case the operating mechanics & stepper motor of the Hydrophase cruise control.
If you stand the spray can in hot water it will spray & penetrate much better, woks on capillary action to get into all the parts.

Next I remove the gas dampers from lower swivel point on the engine hatch and fit some 4x2” wood offcuts so hatch is held open by 2”. That way when the covers are on, as I have a dehumidifier in the cockpit area – the flow of dry air, can get in the engine bay – all is then kept perfectly dry, no mould or damp.
I lower the drive – few reasons, one so no water can be left trapped in it … and also so bellows is not held in stretched position over winter, and trim rams are in retracted position.

Prop is removed, splined shaft coated with anti-corrosion grease, and prop is then sitting in my garage pending polishing with Autosol. The shaft and raer is covered with a plastic bag - bungeed on to prevent insects etc. making a home.

I remove the battery – take in indoors and leave it on a multi-step conditioning charger over winter, (I use a CTEK MSX5.0) don’t leave it on a standard trickle charger – if you only have one of those, best to just put in on charge once a month.
If you want to know why you need multi-state charging take a look here: http://tinyurl.com/d577nsj
While battery is on the boat I have an anti-sulphating unit fitted – prevents early demise of battery due to sulphate build up on the battery plates. Fit & forget unit. (http://tinyurl.com/jo8c8z2)
I disconnect this when it is on the charger.

Final step is to fill fuel tank up to brim, to minimise any condensation forming.


I will cover trailer & boat winterizing in a separate article. (http://www.boatbanter.co.uk/posting.php?mode=post&f=26)
Monterey 194fs with Monster MTK tower + water and SkySki = fun ...... towed by JEEP Cherokee Limited
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