Several 3.3HP Questions

Jester0826

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Jul 11, 2007
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Hey guys, I'm a definite outboard motor newbie. I just "inherited" a mercury 3.3 after my uncle deemed it dead. Turns out it's nowhere near dead, just a little injured. Before I mess with it too much, I'd like to get some basic quesitons answered since I've never messed with an outboard before, and I don't have a mamual (yet). Sorry if the questions get a little lengthy.

First: I'm trying to figure out the year of the engine so I can find a certain part. The engine serial number is 0D912056, and the cover graphics look like it's straight out of the mid-90's.

Second: The main injury of the engine was that it was seized/stiff. It was next to impossible to pull the starter cord, so my uncle thought it was dead. I took the starter off and just gave a nut on the top of the shaft a good tug with a longhandle 17mm wrench and got the entire engine-to-prop shaft turning again. I'm afraid I might have been a little rough to the innards, so is there some sort of oil/lube that should be somewhere in there to keep things running smoothly? I heard that walmart gear lube is supposed to be in there somewhere.

Third: So I got the engine and prop turning again with a bit of elbow grease. The motor started fine and everything was dandy. Unfortunately, I'm an engineering student :redface:, so I had the dorky desire to open up the tiny carb and see how it worked. I managed to lose the tiny, sharp, hexagonal, ribbed, springloaded, pin-looking part. Now the engine floods after a few mins of use, and fuel will actually fill up the carb so much that gas leaks through the seals and drips to the ground. Since then, I've found out that the part's called the "needle", and it controls the fuel intake into the carb. I've found several types of needle&seats for sale on iBoat, but I have no idea which one is the right one. Are they pretty much universal, or do I need to know the specific part number or engine year to buy one?

Fourth: I'm also clueless when it comes to carburetors in general. It looks like the 3.3 carb is basically a small reservoir of fuel with a donut-float inside. The fuel comes in through a valve on the top (off-center). The float pushes a "needle" into the valve (is this called the seat?) to close it off and keep a constant level of fuel. The fuel vapor is sucked up through a tube coming down from the center of the top. Am I correct about this :confused:? Does the needle sit on the top of the float, wedged into the seat? I need to know so I can put it back together later.

Thanks for any help. I know this was a beast of a post, I'll limit my future posts to single questions.
 

nickandm

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Joined
Jul 11, 2007
Messages
21
Re: Several 3.3HP Questions

I have the same engine. Almost the same serial number.

I don't know much about carbs. ( I killed one on a generator). But I do know the lower unit needs gear lube. There are two silver screws on the lower unit to drain and fill it. I have a question for you though. Are you planning on replacing the water pump impeller? If so, could you let me know how to drop the lower unit? Mine only goes down an inch and then stops. I tried prying it with a screwdriver, but it didn't work; and I didn't want to break it. Now I'm stuck, and I don't quite know what to do next. This is my first outboard too so I'm clueless as to what I should do.
 

Jester0826

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Jul 11, 2007
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Re: Several 3.3HP Questions

Thanks, nickandm. I'll be heading to wallymart to get some gearlube.

I haven't done much with the lower unit besides scrape barnacles off and replace the propeller. Since I don't have a manual yet, I've been referring to the simple drawing of the unit on the Crowley Marine website, http://www.crowleymarine.com/mercury_parts/546/120.cfm. The way it looks, after you remove screws #3(2x) and #8, then the unit should drop freely. One thing that might be getting caught is that bevel gear (#10), but I can't really see what parts it would be touching.

The other thing could be the water line that runs up from the impeller. If it's securely fastened to the pump housing, and the other end is secured to the cylinder block, then it could be holding up the entire unit (this only counts if the water pump is attached to the lower unit, not floating freely on the driveshaft).

Another alternative I can give is to get a buddy to rotate the propeller shaft or driveshaft slowly as you gently tug on the lower unit. If there is a key on the driveshaft (the #14 part looks suspicious), then the driveshaft might only slide out of the lower unit if the key is facing forward, or backwards, etc. Rotating the shaft would guide the key into it's special groove and out of the unit. This could also help free the gears if they aren't releasing.

Keep in mind these are all just educated guesses, I've never opened up an outboard motor before in my life. Don't trust me too far on this one. I'm picking up a repair manual from the library tomorrow, so if it has any detailed views of the lower unit, I'll give it a looksee.

Just to make sure I understand you, are the #6 screws the two lube screws you're talking about?
 

nickandm

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Joined
Jul 11, 2007
Messages
21
Re: Several 3.3HP Questions

To tell you the truth, I don't know one numbered screw from the other. I don't have a manual yet. I'm check my library asap though. The oil screws on the lower unit both have some kind of oil marking near them. i.e. oil level, oil, etc.

I'll try your ideas. That's the best lead so far. thanks
 

nickandm

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Jul 11, 2007
Messages
21
Re: Several 3.3HP Questions

Okay, just went to the site you posted. Yes, the screws are #6. Very helpful diagram. thanks
 

Jester0826

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Jul 11, 2007
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4
Re: Several 3.3HP Questions

That website is amazing if you want to figure out how the motor is put together. If you explore the website, then you can find the digrams for the carb, the cylinder block, the ignition system, and more.
 

Jester0826

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Joined
Jul 11, 2007
Messages
4
Re: Several 3.3HP Questions

OK, I got the shop manual from the library. But since it covers every engine from 2.5 to 60hp, it will spend five pages describing the 60hp model, but maybe 1/2 a page on my 3.3. The wording is confusing, and the illustrations are scarce, but here's how it explains removing the lower unit.

1-4. close fuel valve, ground the spark plug (just for safety), tilt the motor up, shift into NEUTRAL.

5. Remove the rubber plug on the port side of the drive shaft housing. Insert an appropriate size socket into the hole and loosen (but do not remove) the shift rod clamp screw enough to allow the shift rods to seperate.

6. Remove the 2 gearcase mounting screws, lock-washers, and flat washers. Then, pull the gearcase straight down and away from the drive shaft housing. It is not necessary to remove the anode screw.

Hope that helps. Check the Crowley website to see how it all fits together.
http://www.crowleymarine.com/mercury_parts/546.cfm
 
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