To understand why the shift cable is usually the culprit you have to understand how the mercruiser alpha one gear shift mechanism works.

The forward and reverse gears are in the lower leg behind the propeller (in the torpedo shaped casing), they are both revolving all the time, one clockwise and one anticlockwise and the propeller shaft runs through the reverse gear and sits in the forward gear at the back of the casing.
Both gears are free to revolve independantly of the prop shaft and the shaft direction is only determined by the position of a sliding ‘dog clutch’ which slides along the shaft and engages with either the forward or reverse gear.

This ‘Dog’ is a cylindrical piece of hardened steel which has ‘teeth’ in either face and slides along splines in the prop shaft, mating up with similar ‘teeth’ in either the forward or reverse gear.

Now here’s the thing
these teeth are slightly ‘undercut’ which means they are sloping backward and this is good in that there is much less chance of them ever jumping out of gear whilst under load, however when the engine is running and there is loading on the prop (ie it’s in the water) These teeth do not want to disengage AT ALL, so heaving on the poor old gear lever would just stretch the cable and achieve nothing.

Mercruiser came up with a simple way to overcome this
They split the gear cable into two separate parts, being the ‘shift cable’ (from the leg to the engine mounted bracket) and the ‘gear cable’ (from the control lever to the engine mounted bracket)

Mounted on the bracket is a mechanism which senses the tension between the two cables and when it reaches a certain level it operates a micro switch, this switch kills the ignition circuit and this in turn takes the pressure off the ‘Dog clutch’ allowing it to disengage with whichever gear it is in.

All this hapens in a split second and should be quick enough that the flywheel momentum allows the engine to continue running.

Imagine what happens when the ‘shift cable’ starts to get old and sticky, now you’re getting the picture, it holds the microswitch over too long and stalls the engine, usually when you’re just coming into a marina.

It Also causes problems when shifting INTO gear, as the ‘stickiness’ causes the mechanism to throw the microswitch over, however this mechanism should not actually flinch at all when shifting INTO gear.

IT IS NOT UNCOMMON TO SEE THESE MECHANISMS DISCONNECTED OR EVEN REMOVED WHEN FOLKS DID NOT REALISE WHAT IT DID.

Some people think that this is related to a ‘start in gear protection’ mechanism but this is not the case. If you are having shift p.roblems, check that the shift cable is not sticking first, it should slide very smoothly when removed from the bracket, but DO NOT TAMPER WITH THE ADJUSTMENT BARREL ON THE CABLE UNLESS YOU UNDERSTAND WHAT YOU ARE DOING, THIS SHOULD ONLY BE CARRIED OUT WITH MECHANICAL KNOWLEDGE AND A MAINTAINENCE MANUAL

Shift Problems can be caused by other factors which can only be assesed with the drive removed,

Sticky slider
Intermediate shift shaft sticking in its bushes
mud or debris around mechanism
Bent shift shaft
To name but a few, however, suspect the shift cable first.

So lets guide ourselves through the procedure. Please note that some people have slightly different ideas and procedures, but we are all searching for a common goal – to prevent damage caused by corrosion and freezing bvoth internally and externally. Remember our principal enemy here is WATER!

First off, we need to ensure our fuel is free from contaminants and water. Using a good quality water absorber fuel stabiliser pour the recommended mixture into your fuel tank. In our case we usually use starbrite ez-store ez-start or water absorber as they are proven products at a reasonable price.

Now fill your fuel tank to the brim (sorry, this can get a bit expensive!). This prevents condensation forming at the top of the tank, potentially contaminating your fuel.

It is also worth changing your fuel filter, ensuring it is primed with a little fuel mixed with your water absorber.

Now that any fuelling issues are hopefully resolved, we can move on to the bigger stuff.

You will need a pair of flush muffs for the next part. These fit over the water inlets on the sterndrive and allow you to flush water through the engine whilst running out of the water.

Connect these up to a fresh water hose and turn on your water supply.

Start up your engine and run it for 10-15 minutes to allow the engine to reach full temperature and to ensure any remaining salt water has been flushed out of the engine.

Now that the engine is up to temp, it is worth changing the oil and filter if it hasnt been done recently. This prevents any harmful contaminants or water from sitting in the engine over winter.

Now for the most awkward bit. You will need to employ a friend / helper / glamorous assistant at this point.

Disconnect your fresh water supply but leave the flush muffs on the sterndrive. Make up a system to pour through a funnel into the sterndrive. We use a funnel and a piece of hose about a meter long, jubilee clipped onto the funnel at one end, and the flush muffs at the other.

Mixup a nice 50/50 mix of antifreeze/ water.

Restart your engine and let your glamorous assistant pour the antifreeze mix into the funnel and through the sterndrive. Continue running the engine until you see the blue of your antifreeze run out of the exhaust outlet, and then pour roughly a household buckets worth through. Then switch off the engine. This is the tricky part. Climb back to your engine and remove the flame arrestor on your carburettor (or intake pipe on EFI motors). Now you need some fogging oil. This will prefent corrosion to the engine internals during layup.

Restart your engine and set the revs to around 1500rpm and spray fogging oil into the inlet. Do this until the engine starts to cough and stutter. Reduce revs to tickover and continue spraying until either the engine dies or 5 seconds. Then shut down the engine completely. The engine will not be restarted, so thats all the running you will be doing for another season! Two important things to note: This process must not take longer than 15-20 seconds. Your running the engine dry and any longer than this can cause impeller damage. Secondly we dont recommend spraying fogging oil into a running diesel engine! This is very likely to cause the engine to ‘run on’ and increase revs due to the engine becoming fuelled by the fogging oil.

Now the most complicated bits are out the way, its time for a little preventative maintenance. Disconnect your battery and grease the terminals (unless you need an auto bilge pump to work). The battery should be regularly charged and discharged over winter to preserve its longevity.

Next, to prevent the belt shredding we mentioned in the last blog post, loosen off your belt tensioner (usually a 17mm nut on a toothed tensioner) and remove your drive belt(s). Next, give you pulleys a quick wire brush or sand to remove any loose corrosion. This helps to prevent corrosion build up during storage that can cause excess wear and premature belt failure. Once this is done you may wish to grease your pulleys. This will prevent moisture getting to the pulley causing corrosion. Remember to THOROUGHLY remove any grease when you relaunch though!!

It is well worth using corrosion guard or a similar product now to spray around the engine and drive, paying particular attention to electrical connectors and any exposed bare metal. Whilst your spraying, make sure to grease and lubricate any steering connectors or linkage parts.

If you can, remove the impeller. It is worth noting that impellers are a service item and should be replaced if they have any signs of brittleness, small cracks or after around 2 seasons use.

Nearly there!! Before we finally put the boat to bed, give the bilges a good clean to get rid of any moisture or damp that might be lurking. If possible leave the bung out of the boat so that if any water does find its way in it is able to drain out. Remember that the bung is missing when you relaunch! If you can, try and get a small tubular greenhouse type heater into the engine compartment. This will keep the compartment warm and moisture free, as well as hopefully reducing the risk of frost further. Ensure that the boat has a good quality, breathable cover over it to help keep it clean and dry during storage.

Finally, take a peek at your sterndrive, checking all the bellows are in good condition and crack free. Again, these are service items recommended for replacement every 2-3 seasons. If there is any hint of cracking or wear, REPLACE the bellows before launch. A leaky UJ bellow can kill a sterndrive, a leaky exhaust bellow can sink a boat! Some engineers like to remove the sterndrive for storage. This is not particularly necessary, but worthwhile if you are going to be swapping bellows out. Remember to use forward gear if you are removing the drive.

Now is also the time to remove your prop if you wish. This prevents the prop from becoming seized over the winter.

Last but not least, check your sterndrive oils level and condition. If it looks to have contamination of any form, replace the oil with a fresh tub or two of your specified brand (hi performance gear lube, ep90 etc depending on application).

And that, finally, is it!

It may seem like a lot, but its all fairly simple and very easy to do for a competent DIY’er. An hour or two on an autumn Saturday should see you done and dusted and your boat in great condition to fire up in the spring.

The best way to break down this question is to first look at WHY you should prepare at all? So lets first look at what problems an engine with no winterisation process can cause:

• Emulsified and creamy engine oil
• Manifold failure
• Starter failure or engine slow to turn over
• Misfires
• Slipping or shredding alternator and PAS belts
• Poor running

All of these problems can commonly stem from a poor layup process and a lack of winterization causing avoidable corrosion.

This is all sounding a bit serious isnt it?! So how can all this damage occur over a winter layup you may be thinking.

Lets examine each point individually:

Emulsified oil:

This goes hand in hand with manifold or engine failure. Creamy oil is caused by water ingress into the engine oil. The two main ways this can happen is through a cracked cylinder block / head and through a cracked or damaged exhaust manifold / riser. These cracks can be caused by the freezing and expansion of water within the engine block or the manifolds. It should be noted that due to the watercooled construction of marine manifolds, failures will eventually be caused by corrosion. However, lack of winterizing causes premature cracking and fractures. We have seen manifolds under a year old fail due to particularly nasty frost!

Starter failure:

As the starters on marine engines sit in possibly the harshest environment for an electrical component they are a common item for failure, particularly after a winter layup. This is caused by corroded terminal and water ingress. The dampness of the bilges, either through rainwater or through lack of cleaning and drainage cause corrosion to both the external terminals on the starter and to components within the starter. Worst case scenarios being a bilge full of water swamping the starter completely!

Slow to turn engine:

Another hand in hand problem here – a tight, slow turning engine can in turn lead to burning out or damaging the starter (see above), or alternatively can be a symptom of a dying starter motor (again, see above). A tight, slow engine is generally the result of internal corrosion, with cylinder bores rusting up, valves not sliding in the guides due to stem corrosion or another worst case scenario in that the engine is hydrolocking caused by water ingress through a damaged manifold. On sterndrive engines drivetrain damage may also cause slow turning particularly due to gimbal bearing corrosion or corrosion to internal sterndrive bearings and gearsets.

Misfires & poor running

A problem very rarely experienced on its own! Generally caused by the corrosion seen above, mild water ingress and also by water condensing in the fuel or damp in ignition system components.

Slipping and shredding of belts

Again, the harsh, damp environment of the bilges can take its toll here. Slightly corroded bottom pulleys can easily rust up heavily over winter, basically giving the pulley the appearance, feel and roughness of sand paper. As soon as the alternator or power steering puts a little extra strain on the belt this roughness can easily wear through the belt causing it to shred through.

So now we can see WHY we should pay special attention to winterizing, we can look at HOW we can carry out a winterisation, and how we can keep the costs down and do it ourselves.

In my next blog post, I will break it down into nice, easy to follow, and almost enjoyable, steps!

This is question we get asked alot, this is the easy
way to identify which one you have.Mercruiser has used several different types of carburetors over the years.
The Rochester 2 Barrel Carb was popular on the early 4 cylinder models and it
was also used on a few V6 and V8/305 GM engines as well.Rochester then stopped production so Mercury Marine designed its own version of the
Rochester 2 Barrel Carburetor called the Mercarb.The Mercarb and Rochesters were mixed in production models.
When ordering replacement carbs, kits or parts you need to know exactly
which carb your engine has.

One simple test can distinguish between a Rochester and a Mercarb.
The throttle base plate of a Rochester Carb has two idle mixture screws.
The throttle base plate of a Mercarb has only one idle mixture screw.

If you have determined that your carb is a Mercarb, then there is one more
identification you need to make.
The Mercarb came with two different styles of accelerator pumps.
One pump rod was straight and cut off flat at the very top. This was the older style.
The other pump rod has a 90 deg bend at the top. This is the newer style.

Chris & Peter stepped up and offered to model them………..

I am undecided if I will run with this piccy on the website just yet…..

So Peter & Chris have been on a mission with saws, hammers and spanners unbolting everything before they eventually chop her up.

The Leisure 27  is a nice sturdy little yacht, and this one was once well loved.

Needless to say we have been listing all the bits and bobs for sale on Ebay , which in a way is nice because at least the boat will live on in pieces on other peoples pride and joys!

The fabulous weather ensured there was an excellent turn out, and everybody that visited our stall was extremely friendly and enjoying their day.
We were amazed by the diverse amount of gear for sale at the show, from £1000 sailing suits to nautical antiques and everything else in between. All day long we were treated to a parade of  boating object d’art ranging from a model motor torpedo boat (which we were jealous of!), coils of rope, brass funnels, folding bikes and literally tins of other gear being lugged around by the bargain hunters!

Our best selling item of the day was undoubtedly boat seats and I think if we had taken a whole van load we would of sold them all!