I HAVE AN OV490 EA ENGINE. THE CARB DOES NOT HAVE A SEAT FOR THE INLET NEEDLE. SHOULD IT HAVE ONE?

Outdoor Power Equipment Small Engine Lawn Mower Repairs Troubleshooting...
Please refer to item number 6 at the above website.

• #6. Main jet, inlet seat

Most often this is caused be an inlet needle in the carburetor not seating.
1) The inlet needle itself can be at fault
2) The needle seat can be damaged
3) Dirt/debris/foreign object caught in the needle seat can hold the needle open causing a syphon effect
4) Debris/foreign material in the fuel can be transferred to the tank
5) Best to use plastic fuel can

I’m happy to assist further over the phone at https://www.6ya.com/expert/rolandw_c013176d62ee17ae

remove and have the carby serviced
could be that the needle and seat are blocked of stuck off, corrosion in the main jet

Hi. Your carbs needle and seat is either dirty and needs to be cleaned, or it is worn. You need to open the carb and remove the float assembly to get to the needle and seat. You can manually operate the float by lifting it up and then blow through the gas inlet pipe to see if needle shuts off the seat.

Needle valve and seat is the first place I would look. Sounds as though your needle valve is sticking in the carb. Since the needle valve and seat is the only way gas enters your engine, it fills the carb bowl, then because it's sticking/leaking, gas starts running into the engine.
Look for trash in the bowl when you remove the bowl. Shut off/drain the gas then pull the fuel line to the carb, pull the carb and spray some cleaner into the fuel inlet after you remove the float and needle valve.

I am going to go with a few taps on the side of the carb around the bowl .. use the handle of a screwdriver .. it is mostlikely a stuck float.. if that doesn't fix it take the carb off pull the bowl look at the needle and seat make sure there isn't something keeping the needle from fitting snugly into the seat. Not sure if the tip of the needle is rubber or the seat it's self on this carb.. one or the other will be. Look for cracks in the rubber. If none I would try to re adjust the float setting ..

The only reason for fuel pouring from the carb is the inlet needle under the metering diaphram is leaking, as the machine has not done a great deal of work it could just be dirt in the seat, you need to remove the metering cover from the carb, remove the diaphram and gasket, you will them see the metering lever connected to the inlet needle, the needle has a rubber tip, clean or replace the needle and blow out the seat.

your float settings inside your carb are set wrong read my advice to resetting them and you should be ok
You'll need to first start off by removing your carb. Be sure to clean the surrounding area to the best of your ability to avoid dirt and debris falling into your carb; or worse, your engine. After you've removed your carb I would suggest a thorough cleaning using carb cleaner (or equivalent) and compressed air to ensure that all jets and passageways are spotless. Avoid using wire or other tools to clean orifices of jets; it's all too easy to alter their original designed dimensions.

After your carb is clean you can now set your float level. The picture below will allow you to become familiar with the parts that are responsible for maintaining the correct float level in your carb. There are four basic parts, the floats themselves (part of the float assembly), the float assembly tang, the fuel inlet needle valve, and the fuel inlet valve seat.


(Float assembly pivot pin not shown.)


It is always a good idea to remove the float assembly pivot pin (already shown removed) and extract the float assembly and the fuel inlet needle. The fuel inlet needle is a wearable part and over time can deteriorate. A worn fuel inlet needle can contribute to an irregular float level. Most fuel inlet needles consist of an internal spring loaded bumper (which contacts the float assembly tang) and a plastic or Viton (rubber) tip. Inspect the fuel inlet needle tip for wear and/or damage. To give you an idea, Eric Gorr recommends replacing the fuel inlet needle/seat assembly every two years. I've found that the average cost is around $15 for both parts.


(Fuel inlet needle shown with Viton (rubber) tip. The Viton is used to isolate the fuel inlet needle from vibration and to create a better seal against the fuel inlet valve seat.)

Now that you've made sure you aren't going to have any issues from worn parts you can reinstall your needle, float assembly and float assembly pivot pin and continue on to set your float level. The float level measurement is taken from the top of the floats (when the carb is positioned upside down) to the gasket surface of the float bowl as illustrated in the next picture. You can use an open-end wrench (sized per your spec), a small metric ruler, or a float level gauge. The tolerance for your float level is usually around +/- 0.50mm.




When setting the float level be aware that the spring loaded bumper on the fuel inlet needle valve may have a tendency to compress under the weight of the float assembly which will skew your measurement. Before you obtain your measurement you'll need to make sure that the float assembly tang just barely makes contact with the spring-loaded bumper. Sometimes it is easier to hold the carb body at a 45-degree angle to avoid compressing the spring in the fuel inlet needle.




If you find that your measurement does not match your float level spec then you can carefully bend the float assembly tang to achieve your desired measurement. Be sure to recheck your work, and if you feel confident that your float level is spot on then you can reinstall your carb and get back to riding.

The needle and seat in the carb is not seating when the float level is high / float bowl full.

This is from the B & S Carb service manual:

An engine that exhibits leakage after it sits for a period of time can be caused by a number of problems. The most common of these is dirt. Any imperfection on a needle or seat surface, such as a small particle of dirt, can cause an engine to perform well in all other scenarios but still leak after sitting a period of time. In addition to dirt, an improperly vented fuel cap can allow pressure to build in the tank which could overcome the float assembly and result in a sporadic leak.


When an engine is not in use, the fuel in the bowl is exposed to the atmosphere via the bowl vent. Fine
particles of dirt or debris that normally would be suspended in the fuel and pass completely through the carburetor, settle out and end up at the lowest point between the fuel inlet fitting and the inlet needle. As the fuel slowly evaporates, the float responds by lifting the inlet needle very slightly off its seat. The dirt present moves in and lodges itself between the needle and seat. Now a slow but steady flow continues into the bowl, eventually showing up as a static leak.

These are the 2 most common causes of carb overflows.

Before replacing any parts attempt to clen the needle and seat area first by removing the float pin and dropping the float down so that any debris can be flushed out.

A new needle and seat is cheap and can be purchased at every lawn mower repair and parts supply. If you do change the needle valve make sure to tke the extra step of removing the old seat and replacing it. The rubber seat gets hard and the leaking overnight symptom can manifest itself again sooner than you might expect.

MAKE SURE YOU HAVE YOUR ENGINE MODEL NUMBER WHEN PURCHASING PARTS

Thanks for choosing Fixya.

Kelly

no spring poss small wire from needle to float! the way it works is float is up needle close because float bowl full--when fluid or gas goes down valve opens lets fluel in.ck full pump disconnect line at carb crank over with guage should have apprx 7psi of press not less then 5psi carefull gas flameable