Fuel injected outboards

[C08]

I recently had a carburettoor problem on a 20hp outboard only 6 years old and 400 hours. The outboard workshop advised that ultrasonic cleaning did not always work and anyway only loosened certain types of gummy deposits but not corrosion. As it was the start of my summer cruise I fitted a new carb and is ok. However I am thinking of getting a 30hp engine as 20 is on the small size for my boat. The 20hp was an old fashioned carb but the 30 hp is fuel injected. My question is whether fuel injection overcomes gumming up problems which with ethanol 10% imminent may only get worse? Also does petrol fuel injection have problems that carburettors do not have?

 

[Assassin]

Considering that they are totally different systems it will cure the problem of the carburettor gumming up.

Petrol injection has several problems and this is determined by the complexity of the system, as a minimum you have to have some form of ECU and a number of sensors within the system to ensure the correct timing of injection and duration of the injectors is correct, this means a bundle of extra wiring and connections to potentially go wrong, lose electrical power and you lose fuel into the engine.

Carbs are much simpler and less efficient than injection and this means you have fewer sensors, no ECU and less wiring and as carbs are simple, they can be dismantled at home and cleaned by people with the most basic of engineering skills using something as cheap as a tin of carb cleaner. Why is corrosion an issue as any carb for a marine environment is very durable and unlikely to corrode as it is more likely to have deposits from the fuel in the float chambers which will harden up if stood for very long periods without fuel in them, or running the engine periodically.

In simple terms, you can resolve one issue and replace it potentially with many others; ultrasonic cleaning is merely a modern gimic and current fad and is rarely effective on items such as carbs as they have too many internal parts which trap and hold anything broken down by U/S cleaning and is the same reason most specialist carb specialists don't use them and strip carbs down and clean them properly.

 

[spannerman]

I work with Mercury, Yamaha, Evinrude, Suzuki, and Honda, and we get very few problems with the injection systems on the 400+ boats we service every year, but every spring we get a flood of customers who come in with their carburettor outboard which has been lying in the garage over winter and won't start. The majority are because they didn't drain the float bowl and there was some water present which has now corroded the carb and blocked the jets. We have an U/S cleaner which has rescued many carbs for us, we strip them and put all the parts in for 30 mins with a mix of hot water and solvent and they come out like new.
We don't experience the typical gumming problems as the injection system is closed so there is no evaporation leaving gummy deposits, but the filtration must be good and the pump/float house needs draining at the end of every season to remove any water that may have collected.