Friday, March 20, 2009

Outboard Engine Trouble - Carburetor Issues

I could quite safely say that 90% of the troubles spearos have with their outboard engines is carburetor trouble - mostly just dirt in them that needs cleaning out.

Ever heard your outboard mechanic say that the carbs were "gummed up" or "full of muck" just before he presents you with the bill?

I do the services on my outboard motors myself for three reasons:
1. To get to know the systems
2. To keep an eye on the systems - helps spot faults
3. Save some money.

You do not normally take an outboard mechanic out to sea with you! So if your motor fails it would be great if you could do a trouble shoot at sea if it is possible rather than call for help or send off you pyrotechnics to attract attention.

So since the dirt in the carbs is an ace problem I will post some of my experience with pics so you can see how easy it can be to strip the carbs clean trouble areas and reassemble.

Symptoms of muck in carbs is normally partial loss of power with engines having two or three carburetors. If you have only one carb as some of the older two cylinder Yamaha's and mariners did then you may have complete loss of power.
On occasion the engine will idle but cannot run at increased revs - as you try to accelerate it dies - not great fun in the surf!!

I will split this into two posts as there are plenty of pics:

First remove the carburetors - fuel pipes and the air inlet cover will need to be removed.

Loosen the bolts securing the outer cover over the air intake.

Now loosen the bolts securing the half of the cover to the carburetors:

Next disconnect the fuel lines - indicated by the drill bit in the pic below and each carb is held on by two nuts with washers - these can be tricky to access on some motors. Start on the top carb and work downwards to the second and third if applicable - this just gives more works space - you may swear at the designers during this stage for their inconsiderateness of the one working on the motor, especially of you do this at sea in a fair chop.

There you have it the carbs are off and ready for stripping and cleaning out of the jets that feed the required amount of fuel to the engine. Also we will clean the bowl, float and the needle and seat which lets the fuel into the carbs. If you do this at home be sure to cover the motor again to keep the dew off the engine and keep all parts safe from pets and kids who could disturb them.

Tip: if you will not get to do this work in one shot then take along you camera to take pics as you progress - it may help for the reassembling part in case you get lost. Alternately if there are two engines - strip one then the other after the first has been put back together - this helps as a guide to see how to reassemble the first one.
In my next post on the carb issue I will strip them - see free strip shows on this blog!!


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With rise in demand of outboard motor covers from usage prospective, they are easily available at various boat shops of Australia.

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