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Reviving an outboard

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I'm buying a new boat that has a Mercury 3.5 HP four-stroke outboard. The motor was running when the boat was stored more than a year ago, but she was left full of fuel and oil.

Obviously I have to drain the old fuel and oil and replace, but what protocol gives me the best chance of reviving this motor without having to take it in for service? Should I do a belt of Seafoam in the first new tank of gas? Go ahead a order a carb rebuild kit? Would appreciate any advice from those who have been through this.

 

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My Honda 2.5 4stroke came back to life after 4 years in the shed.

But  the main jet was clogged  75% with old gas goo.

Was easy to clean as. It was accessable from outside with a screwdriver . So 10min.work and ist was running like new.

So try after checking oil level and watch if  water is coming out of the check  bypass.

 

 

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Clean the carb.  It's almost certainly dirty and you'll need to do it sooner or later so you might as well practice now.

If the motor's maintenance is suspect, wouldn't be a bad idea to go over the major service items.  Better to find out now vs on the water the the impeller is toast, the thermostat doesn't function and the lower unit is only half full of oil.  You don't need any more than a socket set to do this.

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Head over to Harbor Freight and buy their ultrasonic cleaner for around 75 bucks. Pull the carb and put it in. Works miracles. I did this with my 15hp honda. Just used Simple Green and water. Let it hear up a bit and run the cleaner for about 15 minutes. Rinse and reinstall. 

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Another vote for carb removal and cleaning. Pretty simple procedure. Then see if it starts and runs, but make sure you run it in gear, in a bucket with water. I used to service my 4 stroke OB in the spring and would let it idle (and rev it in neutral) in a bucket of water.  Seemed fine. I never bothered to rev it in gear in the bucket. Mistake. Then I got on the water and it wouldn't rev in gear. Rev'd great in neutral, but bogged-down in gear. Lesson learned. 

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Drain fuel from tank and carb.

Add about 4x suggested dose of stabil to a quart of gas. 

Put gas in tank and turn engine over till the treated fuel fills the carb. 

Come back in two days, fill tank with fresh gas, no need to drain treated fuel

Run for 20 minutes.

I've had great success with this method on outboard and motorcycles that have sat for long periods. 

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On 4/10/2018 at 10:34 PM, Alcatraz5768 said:

Have you tried starting it???

Is there an echo in here? And yes, try starting it first.

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If it's been stored wrong side up the engine oil will leak out.  Wouldn't it make more sense to check the oil level before starting the engine instead of after?

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55 minutes ago, Alcatraz5768 said:

Ok, check the engine oil level, then try starting it. 

Nope Check to see if there oil on floor where the OB was stored. If none try starting it.

IF IT AIN'T BROKE DON'T FIX IT.

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58 minutes ago, Alcatraz5768 said:

Ok, check the engine oil level, then try starting it. 

FFS, has anyone tried starting the f'ing motor yet!??!? And yes, it's a 4 stroke, so check the oil, provide new fuel and try starting. Work from there...

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