Subaru engine question

[Flipper]

We have an Outback, I am not impressed with our local dealerships service program, especially when they charged me $60 for a cabin filter, so they are finished. How do you decarb the engine?I was in the marine industry and to decarb a 2 stroke outboard basically you warm the engine then spray Yamaha decarb down the throat of the carb shut if off, let it sit a couple minutes, fire it up take it for a hard ride, shut it down and change the plugs. Same with the Subaru engine?, pull off one of the hoses on the intake manifold or shoot it down the main intake after the air filter? Is the Yamaha decarb basically the same as the Subaru product? And what mileage should this be done? The plugs and crankcase oil are also going to be changed when this is done.

 

[1derer]

I would be very surprised if this car would ever need to be "decarb" if its running rough there is likely a different reason like a throttle positioning sensor or O2, etc... you could also use a fuel treatment like Seafoam pull the plugs see what they look like but if they are fouled chances are there is a cause other then just use.

 

[Graeman]

2 strokes are different and need to decarb due to the fact that they have oil mixed in with the gas. 4 strokes should only need to be cleaned if you see the gunk buildup on the intake. Any good carb cleaner should work to break down the sludge/gunk. Seafoam works great and can be either put into the fuel tank or poured into a vacuum line, but most gunk buildup is before the fuel side of the carb at the throttle valve.

 

[Flipper]

I would be very surprised if this car would ever need to be "decarb" if its running rough there is likely a different reason like a throttle positioning sensor or O2, etc... you could also use a fuel treatment like Seafoam pull the plugs see what they look like but if they are fouled chances are there is a cause other then just use.

Thanks for the response, the car is running fine, saw you tube videos of guys decarbing Subarus, thought it was part of the maintance schedule

 

[Delete Me]

Take a peek at your owners manual. It should give you a good service schedule.

You also need to know if your engine is direct injection or not. I mean if gas is sprayed directly into the combustion chamber adding fuel treatment is not going to work because the treated fuel wont' be flowing past your intake valves or intake manifold. However, it would still help keep your injector nozzles clean. And some manufacturers don't want you spraying cleaners into the intake; air flow sensor, too high temps, etc. I think bottom line is to call service advisor for a particular vehicle and see what service work they offer and why. Then, you can figure out if its something you can do at home or if your vehicle requires special cleaning equipment.

Oh, if your engine doesn't have an PCV oil/air separator then you can add one to help keep the intake clean.

 

[THEpoorguy]

Thanks for the response, the car is running fine, saw you tube videos of guys decarbing Subarus, thought it was part of the maintance schedule

People decarb subarus the same reason why they do rotaries: they burn oil. The horizontal layout of subaru boxer engines means oil sits in the cylinder after shutdown and doesn't just run back like an inline or V engine. Look through any rebuild threads on a subaru forum and you'll see carbon deposits on the lower side of the pistons, due to oil seeping past while shut down and burning. Usually by the time there are enough deposits to justify cleaning it out, the rings are starting to weaken and you'll have oil consumption at a noticeable rate. If yours is NA just keep adding oil and the thing won't die. Odometer has said 125k for the last 3 owners of my car and the old EJ22 still runs fine. If you do decide to decarb anyways, go with seafoam. There are YouTube instructional guides for running it through the fuel tank or a vacuum line.

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