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

It's in decent condition, new rubber impeller, scraper bar and overall good shape. The guy I bought it from said it had been professionally serviced 2 years ago but had seen little use since then as he decided to hire a plow guy to do his average residential driveway. I could not get it to start after adding some fresh fuel that I brought with me so I offered him $ 40.00 and said OK. - he had it listed for $ 75.00 on CL. I'm pretty sure he left some old, unstabilized fuel in there and it turned into varnish.

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.

>>>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. 

well by looking at the picture of the carb sitting upside down the float is setting WAY to low (its out of adjustment by a mile), it will run lean or not at all in that postion....when the carbs upside down the float NEEDS to sit parrelle to the carb base thats VERY important.

and of course as trouts mentioned the float ABSOLUTELY MUST move freely or it will not run.

And yes the SPRING is installed backwards from what l can see.

Niper99 - it's because of that spring.  If the spring was out it should sit parallel to the bowl rim when upside down.

 install the spring so it pushs the float TOWARDS the carb

Niper99, are you sure?  I think the spring it to insure getting needle off the seat. 

nope lm 100% on this one..he could try and run it with the spring off if he wants and will should run but l suspect it could  possiably cause flooding if ran all the time with out the spring.

now that l see the carb lve work on alot of these, and some have the spring and some dont...not really sure why...but tecumseh does the exact same thing..l do know that tecumseh did it because they had flooding issuse on some of there carbs or a rich condition...(sputter)  

I've never seen a float with a spring to force it in either direction.  If I were Frank, I'd take it off just to see how things work without it.  The way the spring works in his set up is to force the float down thus ensuring the needle drops allowing fuel into the float bowl.  That will not cause a lean condition.  If anything, it might limit the ability of the float to fully close the needle.

Regardless of the float/spring issue, I'm with Trouts.  There has to be some tiny orifices and galleries plugged. 

Trouts, the hollow piece in the center that the main jet screws onto is sometimes called the diffuser.  Most of the ones I've seen have very tiny holes drilled across the tube.  As you have said, they also must be cleaned.  Personally, I think it's the orifices in the venturi that are blocked.  Nonetheless, he should pull the diffuser to ensure it's clean.  

like l said before lm not guessing lm telling u that the spring pushs the float UP not down. l have never seen a carb with a spring that pushs down EVER and l seen hundreds of carbs with springs. and l just went out to the shop and double checked my tecumseh stock with the float WITH the spring and it comes with direction on how to install float and spring...and its pushs UP.

and YES the carb will run lean or nat at all if the float is set TOO low which in the picture is how it looks, now l understand what trouts is saying if the spring is pushing it down then ya thats a problem.

but the fact is we cant tell if the float is adjusted properlly or not and in the picture looks way low, it could be the spring pushing down but that seems doubtful becuase there probally would fuel coming out of the carb all the time.  

anytime l have a no start and l want to determine if its flooding or not getting fuel is PULL THE PLUG and see if its wet or dry....its pretty hard to fix a problem without knowing those factors.

with all that said frank.. l think the thing to do is to determine if its FLOODING or NO FUEL. then we can give u a more accurate diagnoses. everybodys got there opinion and thats fine its good to see everybody helping out but it also leads u all over place, even for my self its hard to give an opinion when lm not even sure what u have or havent ruled out.

1..take pluged out blow it dry with compressed air or whatever u got just make sure its DRY.

2..crank engine over sevral times and PULL THE PLUG.

3..is it WET or DRY???

4..if its DRY then adjust your float level so the float is parallel to the carb base when upside down, and place the spring pushing UP.

5. if its WET then it could be a few different things causing it...

start with that first see what happens.

Borat:>>I've never seen a float with a spring to force it in either direction. 

 

   Tecumseh uses springs on many of their winter snowblower engines.  They often get discarded when the carb is serviced. 

 

   From the Tecumseh 4-cycle tech manual.

 

   “Some carburetors use a float dampening spring to aid the inlet valve to maintain a steady position in rough service applications. Note the position of the hooks before removing the float hinge pin (diag. 25).”

 

The Tecumseh spring has two hooks (arms) that stick out.  One rests on the carb body hinge area.  The other goes to the back of the float.  The Tecumseh spring is very weak and won’t push up or down.  It just provides a slight force to the float and hinge I think to reduce float bouncing on the hinge pin. See: http://outdoorpowerinfo.com/repairs/tecumseh_carb_damping_spring.asp

 

     When I get one like this I usually have to muck with it to get it right.  If I remember right one way will make it not work and the other work.  In the wrong direction the spring it too much force to overcome to make the float work properly.  I’ve got three Mikunis here and none have springs (probably lost before got them).   Put it in a class of water with the bowl off and verify how it works with the current spring setting. 

 

Borat>>>Trouts, the hollow piece in the center that the main jet screws onto is sometimes called the diffuser.  Nonetheless, he should pull the diffuser to ensure it's clean. 

 

    Sometimes they are referenced as emulsion tubes and other places diffusers.  On a Tecumseh they are just a straight tube.  I never replace them, only run a wire through.  As a note: the local Honda/Snapper dealer replaces that tube on every carb rebuild.  I’ve never had a problem leaving them in and only cleaning them but that’s only on Tecumseh winter carbs which is what I mostly work on.

 

   A Mikuni is more complex with the series of holes which can draw more or less fuel with increased throttle settings.  They have to be clean.  Normally I would not pull the tube but given the amount of crud in his carb I would.

 

   He has not mentioned a starting problem which he’d have if he was flooding.  I have had carbs that acted like his.  They would wet the plug right after starting but then not start which he had not mentioned.  Whatever, pulling the plug is always a worthwhile check.

    Getting the spring right is easy enough.  The carb is still dirty and needs cleaning.