Outdoor Power Equipment (Lawn Mowers, Snow Blowers, Chain Saws and more) Discussions

I removed the top and back covers and dropped the fuel bowl. It looked like a bad batch of applesauce in there so I cleaned it out and shot the carb with carb cleaner and reinstalled the bowl. It fired up for a few seconds and then died. A good carb cleaning appears to be in order and I'm wondering if I can do this with the carb installed or is it easier/better to remove it from the engine (Suzuki 47P)? I've never removed a carb before but am mechanically inclined and would like to get this operational for next winter.

I remember Borat discussing a cleaning of the jets using wires to remove any build up inside that could cause fuel starvation. I have never done this so any suggestions or tips will be very much appreciated.

   On his carb the slot is for the needle to fit into, >>loosely<<.  The needle tang is smaller than the width of the slot.  There is a bulb end on the tang bigger than the slot to pull the needle off the seat when the gas is low.   The tang goes on the bottom side of the slot.  His looks right.

    The solvent will not clear all crud but even the worse will usually be soft enough to break with carb spray.  So, poking with the wire, carb spraying and air wash still required. 

     Possibly you have the jet removed but in the pictures above there should be a jet at the bottom of the tube in the center of the carb.  If that was plugged it could cause what you have for a problem. 

    Poke up through the center tube inside the main tube.  

    There are holes on the right and left sides of the body which I'm not sure about.  They may be air ports but you can partly poke in there. 

    Looking into the choke side of the throat there may be holes on the right and left side about half way up.  Prod in these. 

   On the manifold side under the gasket there may be 4 holes to poke in.  You may not have those holes on your model.  My Mikuni has them. 

   On the screw head side of the low idle screw there may be two jets.  One is fixed and I think has a through hole.  I can't remember but I think that is a low speed feed limiter. 

   There should be another screw close to the top edge with a spring.  I think that controls air for high speed fuel control.  I think that one is set backed out 1 1/2 from lightly seated (It might be 1).  If it runs poorly tweak it.

Note how the float sits in this photo. It does not move freely but is more spring loaded (down pressure). I can move it up but the spring action forces into the position seen in this photo - even if I tip the carb upside down. Does the needle need to go in a specific way???

See how the needle is positioned - it really can't go any other way.

Looking down the throat.

One more that shows how the float is positioned.

The spring could be in correctly or incorrectly, I forget.  Most of the Mikuni carbs I've worked on did not have springs.  Maybe the spring is in backwards.  It does not matter.  What has to happen is the tension has to be small enought that the float alone can overcome it.  You said the flow stopped when you tested that so the tension is probably ok. 

When you have it like you are holding it and the float falls to its stop it's ok.  When you tip it over the float should be level with the bowl gasket rim.  That won't happen with yours because of the spring.  You can pull the spring can check where the flot ends up when the needle seats.

Looking into the choke side there are two internal holes that can be seen in the throat that should be prodded.  

You still have the minifold and gasket on.  Those should come off before tanking.   I think there will be 4 holes in back of the gasket which must be clean and prodded.

In the prior pictures it looked like the plastic bowl stop was cracked.

Do you have the jet that screws in by the bowl stop?

Did you take out the low idle feed screw on the top of the carb and clean it and in there? 

Also, the air feed screw next to it, the black one?   Those usually are brass and have a spring on the screw.  Never saw a black one.  It looks like the type that only has a hair of adjustment.  Maybe they are like the Hondas and have to be broken to get at the screw.  ??  If you can that one should come out and be cleaned and inside cleaned.

The needle does not go in a way other than the way it must go.   The only way it will fit into the hole and slot is the way it is in the pictures.  It's fine.  But it must move freely other than the spring tension.  It should be able to go up overcomming the spring by the force of the float lift from the gas rising.  You'll have to guess that. 

What you've cleaned is external parts which is essential to stopping crud from falling off and plugging something.  What matters is the passage passageways, ports and jets to be clean like the body.  The float looked like it had varnish.  The body looked like it had prior white aluminum powder buildup with a varnish cover on top.  Both are tough to deal with in hard to reach passageways.  If not white buildup then it's probably piles caused by the oil evaporation.  Two cycle gas evaporation can be very weird and many types depending on the gas, oil used and how the buildup happened.

You can test the float action as is by dunking what you have in a class filled with water.  Does the float raise and lower properly?   You can test how soon the float lowers the needle by putting on a 1 foot section of gas line and then fill that with water.  I test needles like that all the time for seating.  Get a class with a mount that is just big enough to sit the carb body on.  Then fill the gas line (pointed up).   You should be able to fill the tube and let it sit for an hour and the level not drop any amount.

SO:

1. Insure the float is freemoving.

2. clean the jet at the bottom of the tube in the center of the carb.

3. clean emulsion tube

4. clean the ports on the manifold side.

5. clean the jets by the low idle stop screw.

6. clean the ports in the choke side of the throat.

7 prod the holes on either side of the body.

>>>I'm wondering, that the carb might cleaned properly but the screw settings might be out of adjustment.

   Could be but I doubt it because of the things below - as far as adjustments.  His does not have a nut from the bottom like a Tecumseh nut with those two holes that get plugged all the time.  His had a solid nut.  The metering hold is on the jet that screws into the base of the tube that sticks down from the center of the carb body.   He's never shown it in the pictures.  If that's plugged it's like the nut holes on a Tecumseh being plugged.  And his has others - the 4 ports on the manifold side mentioned in another post and here.  You were right twice and still right.  He's got dirt someplace(s).

Yes, it has a low idle screw just like on a Tecumseh.  That’s the one that is a physical stop to the butterfly. 

There is also the gas feed low idle jet but it’s just screwed in.  It’s not settable like on a Tecumseh.  It’s got a screw like plug that screws in.  The bottom of the plug part has a hole in it which is the low idle metering flow control hole (jet).  

There is a high main jet on the top of the carb body.  I think the way it works is the high jet controls the flow of air which controls gas flow.  His has a plastic part I’ve never seen on a Mikuni.  It’s like the plastic stops on a Honda carb jet.  At least that’s what I think it is.  It’s a plastic stop so people can’t mess with it.  On a Honda you can break off the plastic and access the slot for the screw.  On his I’m not sure.  If his is a non-removable cover then that’s a problem for cleaning access and a positive for doing a dip.  BUT, I think the 4 holes I mentioned at the back of the carb on the manifold end lead to that jet.  He can prod and squirt in through those ports. 

Chances are pretty good that there is internal varnish buildup.  Frank, remember to separate the gasket and manifold before the dip.