Dinghy outboard motors - Caring for your carburetor (Part 2)

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In the first part of this series (See MW190), we saw how to carry out the basic overhaul of an outboard motor, starting with flushing the cooling system to prevent rust from invading the block. We then turned our attention to replacing the engine oil and gearbox oil to ensure proper lubrication. The fuel system is another essential element in the smooth operation of an outboard motor, and must be regularly maintained to prevent breakdowns which, by definition, never happen at the right time. Shifting the tank around in the dinghy and exposing it to the elements - not to mention poor-quality fuel - are conducive to the proliferation of dirt and bacteria, which can clog the carburetor. It’s always a good idea to carry a jerry can or a spare tank with clean fuel. In this respect, it’s important to store spare gasoline in fully-filled jerrycans and/or containers, as trapped air is likely to lead to condensation and thus pollute the gas. After two months’ storage, this fuel should be used up and replaced, as it ages very badly. This chapter deserves a brief aside concerning the fuel itself: even if outboard manufacturers don’t give precise specifications on this subject, always opt for fossil fuels and not biofuels.
In addition to all these precautions, we strongly recommend that you dismantle the carburetor once a year for proper maintenance. Outboards can easily stall due to a clogged carb. Having a carburetor maintenance and repair kit on board, including replacement gaskets and jets, will mean you can get back under way as quickly as possible.

Philippe Bauer, from Tendance Voile, dismantled the carburetor on this 8HP Yamaha to give it a good clean and change the gaskets and seals. His advice is to take photos during disassembly and be tidy when removing components. We start by draining the bowl after having emptied the fuel lines.


1/ The fuel filter can be seen under the intake hose. In the event of an engine problem, you can start by cleaning it and changing the filter if necessary.


2/ The carburetor is now removed - after removing the air intake hose.


3/ Now it’s time to disconnect the fuel inlet and remove the air intake housing.


4/ Next, separate the fuel bowl from the carburetor body, taking care to put the bolts and other components in a pot or jar.


5/ The jet (tube with a slotted head) vaporizes the fuel and can be liable to become clogged with dirty gasoline. If the motor won’t idle properly, it’s often because the jet is clogged. Unscrew it and blow it out (blow it out by mouth if you don’t have access to a compressor). Don’t use a needle, as it could damage the jet.


6/ The fuel bowl we see here isn’t that shiny. After disassembly, a good cleaning with WD40 is called for... As for the seal, it has to be changed and replaced by the new one supplied in the kit.


7/ Once the jet is clean, it can be reassembled by screwing it in as far as it will go - be careful not to ...

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