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

I have been working to get an leaf loader ready for fall clean up. The 11hp briggs and stratton engine starts briefly when choked and then dies. Gas runs out and drips below. It runs all of 3 seconds before it dies. I've tried starting it without the choke but no luck there. When I bought it a week ago the previous owner started it on the first pull. It has a good spark, fresh gas, a clean air filter. With the spark plug pulled I can see the spark. I've tried starting it at half throttle, full throttle and low throttle. No difference there. I took the bowl off the carburetor and cleaned out the crud that was in there. Do I need to take the carb off and completely clean it? What setting should the throttle be at for start up? Any suggestions? the motor is a Briggs Industrial Plus model 256422 type 1015 -E1

I did remove the fuel pump from the engine. I inspected it carefully. I leaks, mostly at the seams where the gaskets should be sealing the pump casing. The diaphrams (there are two inside) look fine with no rips or tears or signs of distress.
I remain baffelled however. I'm not sure that the leaking fuel pump was my source of trouble with respect to the engine's problems. With the pump still attached and the carb bowl removed I could pull the starter cord watch the gas pour from the needle valve hole just about the float. Gas has definitely been making it into the bowl.

Would I be safe in ruling out the fuel pump as the source of my problems? The symptom being a engine that would start when choked and then quickly die. Either you're getting gas into the bowl or not. I don't see how the leaky fuel pump would play a role.

is the plug wet or dry when it doesnt start (pull out and inspect)? well if fuels going to the carb then either your carb gots dirt in it blocking fuel entering the engine or a possiable intake leak/head gaskets leak which doesnt sounds likely due to the engine runnig fine when u bought it. if the engine doest have compression it wont be able to suck fuel into the engine. make sure the intake and carb are tight. l would lean towards carb being dirty l would clean again and make sure the idle circut and main jet are clear.

Cleaning the carb makes sense. Can you provide any advice in doing this. I have never worked on a briggs carb before.

I do have compressed air and carb cleaner.  I cannot seem to figure out how to remove the carb.  I thought I might try to clean it while it is still attached to the engine.

Is fuel comming up the main nozzel in the carb behind the choke butterfly when it floods? If so the needle/seat/float is causing the problem...

or...
The fuel pump may be leaking internally to the "vacuum side of the Diaphram", meaning that the fuel is making it to the carb also through the vacuum port on the intake manifold..(I think that is where the pump hooks up on this motor, correct me if I am wrong...)

Try starting the motor with a pair of vice grips on the Vacuum line from the pump after the bowl is already filled with gas. If it still leaks this will rule out pump vaccum side failure...

Try taking the pump completely out of the loop, hook up a fuel tank and gravity fill the bowl of the carb with it... If you have a float/ needle/seat problem, the carb will leak by gravity feed also..


Good luck,

Friiy


Ps.... How did the tiller work this spring?

<BR> friiy wrote: <BR>With the air filter off, I do see fuel in the carb behind the choke butterfly. But I cannot confirm that the fuel is getting there through the nozzle as you suggest. I went ahead and replaced the fuel pump yesterday with a new one and it no longer drips. Without the fuel pump the carb does not get gas (the tank is slower than the carb). When you pull the starter and let the bowl drop down the fuel flows right through (I catch it with a cup). If you raise the bowl up with your finger, the fuel flow stops (even if you continue to pull the starter cord). I spent the day yesterday cleaning things I got the main nozzle out (carefully) and cleaned it really well. I installed a new fuel line, the new fuel pump, a new fuel filter and flushed the gas line. I slid small wires through the little holes and used a can of carb cleaner with a straw tube to blast the cleaner through all the holes that I could see. The I ran my compressor up to 100 psi and blew everything out. I also put in a new spark plug and changed the oil. <BR>I pulled the starter cord (choked on) and the engine fired right up and the died quickly. If I let it sit for 20 minutes and leave the choke off, it will fire right up again and then die. I'm baffled. I'm stumped. <BR>It really was running fine when the previous owner started it just over a week ago. That's why I purchased it. It ran so smooth. <BR>There is a small white wire dangling unconnected below the carb. Maybe something came disconnected. <BR> I thing I'm missing something really basic. Something foolish. The leaking fuel pump was just a distraction. <BR>Is there a factory setting for the idle mixture screw. I got that off by removing the safety shroud around the muffler but I'm not 100% sure I got it back where it was set before. <BR><BR><BR>The tiller is fantastic. I had used a front tine Merry tiller before but there's no comparison. My neighbors have all borrowed it as well. I'd like to add a sickle bar to the BCS someday. <BR><BR><BR>

Sounds like you still have something in the fuel system plugging the high speed circut... Does the carb tower (post that runs through the float that the bolt screws the bowl on) have a jet on it, or is the jet drilled into the bowl bolt? Check these for grit that may have settled there.. Post pictures of the carb with the bowl off, if you would.

Don't worry about the idle mixture screw at this time, set it at about 1 and 1/4 out from soft stop.. That low speed circut is not running unless the throttle shat is almost fully closed. Adjust that after the unit is running, warmed up and at idle.

So, is the carb not leaking any more? Are you sure the bowl is full of gas?

Post some pictures of the carb with the bowl off if you can..

Good luck,

Friiy

I'll work on getting some pictures of the carb. I know that there are some hole that I could not reach without removing the float (I did not remove the float because I did not remove the carburetor from the engine, I've never taken one off a Briggs and I was worried I'd ruin something. On the outside (air intake side) of the choke plate I found some small hole to clean. But I have a feeling that there may be more of these holes further in near the other (throttle?) plate. I could not reach those. This afternoon I pulled it and it ran (rough) for almost 10 seconds. &
Question: When I slide a small metal wire down the hole on the left side of the carb it goes all the way in. When I try to do the same on the hole on the other side it only will go in 2 inches. (Cycled in green) I'm not sure if this is normal. <BR><BR><BR>&gt;<BR><BR>This is the location (yellow square) that I could not reach without removing the float. &lt;BR&gt;&lt;BR&gt;&lt;BR&gt;&gt;&lt;&lt;

The holes on the carb are the emulisfier vent and the carb bowl vent.. I could not tell you which is which unless I had more pictures. The holes go in so far and then are drilled 90 degrees through the access behind the welch plugs (silver discs pressed into carb body).

The carb bowl vent keeps the carb bowl and fuel at static pressure (outside air pressure)the low pressure of the air in the venturi draws fuel through the main and low speed jets...

The emulsifier jet is a port that injects air into the main jet fuel stream (through all the little holes in the nozzel) so the fuel "sprays" instead of bubbling up and pooling in the bottom of the venturi..

Don't worry about the wire not going through. Just spray in the hole and make sure it comes out the vent above the float and the emulsifier jet comes out where the nozzel screws in...


Good Luck,

Friiy

friiy wrote:

When I look into the carb while pulling the starter I don't see gas being sprayed.  Instead I see it bubbling up and pooling around the top of the brass nozzle. Right behind the choke butterfly  where the brass nozzle pokes up and enters the carb.  Where is the venturi?

  

The spray shouldn't happen till the engine is running. On Choke-starting with a pullstart, a large vacuum is created to draw "rich amounts" of fuel into the venturi..

The venturi is the narrowing throat of the carb in the middle...(as air velocity increases at the venturi, pressure decreases, thus drawing fuel through the jets to the low pressure area)

I don't understand, is the carb still flooding when it starts to run, or is it acting like it is running out of fuel? Was fuel bubbleing out of the carb as it stopped?


Friiy