Draining Carburettor Bowls

[Bigted]

I have a 1993 Yamaha 175 BETO 2 stroke and I want to know how to drain the carburettor bowls. Can anyone describe (accurately) from the photos, which plug(s) to remove? Sorry that the photos are on their sides.
Any help appreciated.
Ed

[Geoff54]

I don't know that specific engine but I believe that you have a double barrel carburetor with two float bowls. You would need to remove the drain plug from each side to drain the separate bowels. The drain plug would be the copper colored hex with a slot to the left of the pictures. The one between the linkages on one side and the corresponding one on the opposite side. Some designs just need to be loosened, and may have a spring, while some have to be removed completely.


edited for clarity

[a64pilot]

Usually two or four barrel carbs share one float and one float bowl.
It would appear in your photo that your drain bolt is pretty obvious, but strangely it almost looks like a jet, but I’d remove it and see if fuel comes out.

[Geoff54]

Originally Posted by a64pilot

Usually two or four barrel carbs share one float and one float bowl.
It would appear in your photo that your drain bolt is pretty obvious, but strangely it almost looks like a jet, but I’d remove it and see if fuel comes out.

"Usually" is the key word here. Some Yamaha outboards used two barrel carbs with two float bowls - effectively two carbs cast as a single body. I believe this is what we are looking at here.

[Shrew]

That large bronze head doesn't look like a typical drain plug. It's hard to tell, but it looks like I can see a smaller bronze bolt on the bottom of the fuel bowl in the background. The angle of the pics are from slightly above, so don't really give us a good image.

A service manual would be tremendously helpful right now. Something to consider buying if you are attempting to do your own service.

[belizesailor]

Loosen/remove the screw circled in blue. Some are drilled with channels so that when loosened they drain...you may not need to totally remove it...also why it looks like a jet. Lower carb should be identical.

[Geoff54]

Here you go. Not sure if this is EXACTLY the same engine but it's a 1993 175 2-stroke. #6 is labeled "SCREW,DRAIN". Google is your friend.

[Bill O]

From the parts diagram for that carb/motor the hex head w/slot is actually the main jet (one on each side of the 2 barrel). From the parts diagram there is a drain located underneath/to the side the jet. It can be seen in the pic from belizesailor (it looks like its on top in the side ways pic).
If you remove those main jets, don't lose them as it appears those are not available for replacement.


Bill O.

[Geoff54]

Originally Posted by Bill O

From the parts diagram for that carb/motor the hex head w/slot is actually the main jet (one on each side of the 2 barrel). From the parts diagram there is a drain located underneath the jet. It can be seen in the pic from belizesailor
If you remove those main jets, don't lose them as it appears those are not available for replace.

Look closely. #15 is the main jet. #6 is the drain plug below that - the one with the little line that goes to the bottom of float bowl. One #6 on each side and, yes, #6 corresponds to the one the belize circled.


CORRECTION. I think that the one circled IS the main jet and the drain is not actually shown in the photographs.

[redneckrob]

If the engine still runs then by far the easiest way to drain the carburator bowl is to disconnect the fuel line while it's running and let it run until it stops. If it doesn't run, then you're taking the carb off anyway right? Just put some shop towels under it and the fuel will drain out various places as you remove it.

[Geoff54]

O.K. humble pie here.


I just looked more closely at the pictures and the one circled by Belize is marked "126" whick would almost cirtainly be the main jet (#15 on the diagram). Looks like the drain bolt (#6 on the diagram) goes in from the side and is below that, not visible in the photographs or possibly the one just in front and below that. As I said previously, I am not sure that the diagram is the exact same model.



I have come across float bowls that didn't have a drain screw and the bowl had to be removed. I don't think I have ever encountered one on a Yamaha though.

[Bill O]

Originally Posted by Geoff54

O.K. humble pie here.


I just looked more closely at the pictures and the one circled by Belize is marked "126" whick would almost cirtainly be the main jet (#15 on the diagram). Looks like the drain bolt (#6 on the diagram) goes in from the side and is below that, not visible in the photographs or possibly the one just in front and below that. As I said previously, I am not sure that the diagram is the exact same model.



I have come across float bowls that didn't have a drain screw and the bowl had to be removed. I don't think I have ever encountered one on a Yamaha though.

Thanks, feel somewhat vindicated here!
Hard to tell but I believe the smaller screw in belize's pic (in the blue circle) is the drain.

rnrob. Would agree to run the carb dry when setting the motor up for a while, but if crud/water is sitting in the bottom of the bowl the best way to get it out is through the drain.


Bill O.

[Geoff54]

Both screws are within the circle belize added. I think he was indicating the main jet but also has the other screw within the circle. It could be the drain but I'm not certain. Honestly, a long as you are careful, it doesn't do any harm to remove it and see.


As to running the carb dry - it depends. I like to drain them occasionally or if I am putting an engine away for the winter as it ensures any contaminates are also drained.

[redneckrob]

Originally Posted by Bill O

Thanks, feel somewhat vindicated here!
Hard to tell but I believe the smaller screw in belize's pic (in the blue circle) is the drain.

rnrob. Would agree to run the carb dry when setting the motor up for a while, but if crud/water is sitting in the bottom of the bowl the best way to get it out is through the drain.


Bill O.

Makes sense. I do have my doubts on how effective that little plastic fuel filter is at catching anything smaller than a small stone.

[belizesailor]

Originally Posted by Geoff54

Look closely. #15 is the main jet. #6 is the drain plug below that - the one with the little line that goes to the bottom of float bowl. One #6 on each side and, yes, #6 corresponds to the one the belize circled.


CORRECTION. I think that the one circled IS the main jet and the drain is not actually shown in the photographs.

Originally Posted by Bill O

From the parts diagram for that carb/motor the hex head w/slot is actually the main jet (one on each side of the 2 barrel). From the parts diagram there is a drain located underneath/to the side the jet. It can be seen in the pic from belizesailor (it looks like its on top in the side ways pic).
If you remove those main jets, don't lose them as it appears those are not available for replacement.


Bill O.

Interesting....odd place for a main jet.