boat owner

When using a spare pump as

the quick-change standby, it

is important to be able to

remove the hoses quickly

and easily. Marine reinforced

hose, which is used to avoid

collapse under pump suction,

hardens over time – and often,

the only way to disconnect it is

to cut it off and renew it. This

is clearly of no use where the

pump needs to be changed

quickly. On this installation,

vehicle hoses are used for the

final short connections to the

pump as they never harden

and are always easy to

remove. The main pipe runs

are all domestic copper tubes

which are cheaper than

reinforced hose, and there is

no problem with pipework

collapse. Where it is essential

to use convoluted hose, it is

possible to make up an end

connection using a copper

tube stub 4 or 5in long,

depending on the diameter of

the hose, in the appropriate

size to fit inside the hose. The

end of the convoluted hose is

warmed slightly in hot water to

soften it and the copper tube

is secured halfway into the

tube with two hose clips for a

permanent fix. Then, use a 4in

length of vehicle hose on the

exposed end of the copper,

again secured with two hose

clips. This hose is used to

make the final connection

onto the pump with a single

hose clip and ensures it can

be fitted and removed very

easily while still providing a

reliable seal every time.

The quick-change standby

Thermostats are often forgotten

but they can eventually go

wrong, and usually in the closed

position – which means the

engine overheats quite quickly.

Less serious is when they fail in

the open position, as in this case

the engine simply never reaches

its correct operating temperature.

The quickest cure for a closed

thermostat when away from

home is to simply remove it

and fit a replacement at the next

convenient port of call. For an

open thermostat, simply keep

a careful eye on the engine

temperature to ensure that it

doesn’t decide to close. Again,

replace it at the next convenient

point. Test the thermostat by

placing it in a pan of hot water and

watching to see when it opens. As

long as it opens before the water

boils, you can assume it is OK.

For a more accurate test, place

a thermometer in the water and

check the temperature when the

thermostat opens. Thermostats

usually have the operating

temperature stamped on the case.

Thermostats can be mounted in various ways, but generally speaking

they are easy to get at and can be removed and replaced by removing

the housing, lifting the old one out and fitting the new one. Fit a new

gasket to ensure the housing doesn’t leak after replacement.

Check the thermostat

The raw water strainers need to be checked

1

The raw water strainers need to be
checked on a regular basis, especially if
cruising in shallow waters. A quick flush-out
with clean water is all they need.

2

Make sure the pipework to the strainer

is not partially blocked by rodding it

through after cleaning the strainer basket.

3

Check the cover seal is in good

condition and give it a light greasing

to help it seal when the cover is refitted,

otherwise the system may not prime.

TIME TAKEN: Average 1 day

COMPETENCE LEVEL: Intermediate

UK COSTS: Spare pump, from

£100-£1,000 depending on make

and size of engine

■ Alternator and pump belts, average

of £3-£5 per belt

■ Impellers, from £10- £150 depending

on make and size of engine

■ Thermostats, less than £10

...And finally

The final engine service item, once
everything has been reconnected, is
to refill the heat exchanger system
with a 50-50 mixture of good quality
antifreeze and water and recheck the
level after the engine has run up to
temperature and cooled again.

Cooling system service