Mercury 90

[Virgo67]

Hi folks,

I bought a 5m RIB with a mercury 90 outboard, wondering what maintenance/service I need to carry out with the engine thru the winter if any?

Should I run with a hose it once a month to keep it ticking over?

thx

[Pikey Dave]

4 stroke - 2 stroke-carbed or EFI??

[Virgo67]

sorry, 90HP 4 strike EFI

[Pikey Dave]

Originally Posted by Virgo67

sorry, 90HP 4 strike EFI

In that case I wouldn’t do anything apart from give it a good flush & give the head a spray with silicone. Don’t drain the fuel or run it dry.

[Jon Tallis]

In addition to what PD says above, I'd recommend winterizing it with fogging oil.
Store it trimmed fully down so you don't risk water freezing in the lower unit.
If you've just bought it, now might be a good time to do a full service and winterize it afterwards so you know you're good to go in the spring whenever you want to dust it off. Shame to miss the first glorious weekend of spring waiting for an obscure part.

[Pikey Dave]

Originally Posted by Jon Tallis

In addition to what PD says above, I'd recommend winterizing it with fogging oil.
Store it trimmed fully down so you don't risk water freezing in the lower unit.
If you've just bought it, now might be a good time to do a full service and winterize it afterwards so you know you're good to go in the spring whenever you want to dust it off. Shame to miss the first glorious weekend of spring waiting for an obscure part.

Personally I wouldn’t fog an EFI 4 stroke & I’d leave the service until spring, I wouldn’t want the (new) impeller sat all winter. That’s just my opinion, I’m not saying it’s right or wrong, just my way of thinking.

[69cmw]

Why even winterise it?
You get some cracking days over the winter for boating.

[Jon Tallis]

I guess I read the OP's question in the context of laying the boat up....but yes...if you have the chance to use it, keep it in commission and use it. I've had some cracking days out in the depths of winter[emoji16][emoji3063][emoji16]

[whiskylee]

Bill Higham’s Outboard winterisation process!

Top off all fuel tanks using high octane fuel, and add Lucas fuel stabiliser to the fuel at the correct ratio link to the right stuff: Lucas fuel stabiliser

Carburetted engines remove carb covers, fuel injected engines remove air box to expose throttle valves

Run the engine for 20 minutes to run high octane stabilised fuel right through the fuel system, check water circulation at intervals during running

Put engine on fast idle around 2000rpm, squirt fogging oil into each carb/throttle valve opening. This will make clouds of white smoke which is Normal, 3x 3 second bursts to each induction hole is about right, swap cylinders between squirts

(This step is only necessary if you store your engine in a damp cold climate for a protracted period) stop engine and remove spark plugs, squirt fogging oil into each cylinder and crank engine for a few seconds before re-fitting spark plugs.

Remove kill cord and flywheel cover, turn flywheel in clockwise direction one turn by hand, this ensures impeller is in correct position for storage.*

If your engine has carbs drain them of all fuel using the carb drain screws.*

Spray all linkages, carbs and mild steel parts with spray grease, spray all other surfaces under cowling with corrosion guard.*

Remove prop and thrust washer, and grease prop shaft, grease all grease nipples, remove steering cable and grease.*

Check gear oil quality and level.

If 4 stroke engine check engine oil quality and level.*

Tilt engine down to vertical position and wash*exterior of engine with soap and water and treat with storage seal or similar.

Close vent on fuel tank, disconnect battery and trickle charge occasionally.


I hope this has been helpful to you

Yours in Boating,

Simon Higham

Just came through on my emails from higham marine, some good pointers