Fuel cutoff switch?

[arch252]

You lost me Senior. I know my explanation was pretty confusing. The carbs I am used to working on have the small solid metal (aluminum, I believe) needle and the little black, or red, needle valve seat, or ring. That what I'm used to pushing down or seating with the back end of a drill bit.

The needle on this carb, like one other I have seen, has a black tip. Polymer you say and I suspect that's correct. That's the kind of needle this carb has. When I went to "fish out" the seat, there was no seat, just the metal base inside the hole where the needle fits in.

I was saying that the other carb I worked on with the black tipped needle also had no seat. That led me to believe that these newer black tipped needles are meant to seat directly into the metal opening, with no rubber seat or ring to install into the valve opening.

I'm sure this is a no brainer to you pros, but I'm not used to working on newer engines, or vertical shaft engines either. Most of my experience is with the old Briggs and Tecumseh horizontal engines.

 

[arch252]

Sorry, just re-read your post, neoprene, not polymer as I said. At any rate, hopefully you got the gist of what I was saying.

I really need some feedback on how I will know if the problem is fixed, could someone tell me if I am on the right track with the manifold opening deal?

 

[SeniorCitizen]

I not a pro on small engines and I haven't worked on a newer carb since they started using a rubber seat insert. I suspect the rubber tipped needle was replaced with the rubber seat because of easier manufacturer. I can see no reason for both rubber tip needle and rubber seat.

If were talking about an engine with a rod and piston assembly weighing around 1,200 lbs. then I could visit with you like a pro.:laughing:

 

[arch252]

LOL, I'm more comfortable with one weighing about a pound! At any rate, I think we agree on the needle and seat issue. Unless someone tells me otherwise I'm assuming there is no seat to fish out of there and replace.

The only issue I have remaining is how I can determine if the problem is fixed. I don't want fuel running into my crankcase and I need to know how to find out if it is. I suppose I could just drain out the oil and leave the drain plug out and then turn the fuel cutoff switch on so fuel is running to the carb and then leave it for a day or two and see if fuel starts to drip out. I'd like to find a more immediate way to testing it though.

 

[SeniorCitizen]

LOL, I'm more comfortable with one weighing about a pound! At any rate, I think we agree on the needle and seat issue. Unless someone tells me otherwise I'm assuming there is no seat to fish out of there and replace.

The only issue I have remaining is how I can determine if the problem is fixed. I don't want fuel running into my crankcase and I need to know how to find out if it is. I suppose I could just drain out the oil and leave the drain plug out and then turn the fuel cutoff switch on so fuel is running to the carb and then leave it for a day or two and see if fuel starts to drip out. I'd like to find a more immediate way to testing it though.

A more immediate way to check float / needle valve function would be to disconnect the fuel hose from the fuel cut off valve and elevate the end above the carburetor. Using a string and the clove hitch knot ( I did show you how to tie that knot didn't I ) tie it up so it stays elevated. Fill the hose with gasoline until full and stays completely full. This will have filled the carb bowl. If the needle valve is holding as it should the gas level in the hose will stay full all except for a small amount of evaporation over several hours.

 

[arch252]

Now THAT is experience and we wisdom. That sir, is exactly the reason I get on this forum. I could have stared at that for 6 months straight and I would not have thought of that, makes perfect sense. Thank you very much sir! ☆☆☆☆

 

[arch252]

I did what Senior described and there is no doubt that fuel is still bypassing the float. Slowly but steadily the fuel level kept dropping in the elevated fuel line. I can't figure out where it's going though. I left the bolts loose and a small gap on the carb to engine intake manifold, the only place where fuel could enter the engine. Fuel never leaked out of the manifold opening. I could see the fuel pooling in the bottom of the air filter housing but that is above the manifold opening level. So if the fuel is pooling in the bottom of the air filter housing where is it going from there? The photo is looking down into the air cleaner housing.

At any rate, I'm going to go ahead and get a carb kit and install a new needle and try it again.

 

[upnorth]

I got a briggs 13.5 hp engine with a number of 28N707 0166 01. When I go looking for information, I find this same engine number on a 15 HP engine. Somebody ain't doin their homework!
Anyway, I got a solenoid mounted underneath the float chamber on my carberator. it has two wires on it. one goes to chassis ground, the other's supposed to go to the ignition switch [on position]
polarity doesn't mean anything here because the solenoid is [above] ground.
When mine failed to operate one day, there was no power [12 volts] from the ignition switch. I installed a single pole switch directly off the battery and to the solenoid coil. Now when I start the mower I just flip up the switch, which opens the solenoid and allows fuel to flow, and further advance the key switch to the "engine start" position. Engine fires right up. release the key switch and it returns to the "on" or "run" position. And go about my business.
When I'm done I put the keyswitch in the "off" position and flip the toggle switch to off. Fuel is shut off to the carb and the engine stops. So whatever fuel is still in the line burns and the engine stops.

 

[arch252]

Sorry for the delayed response, been on vacation in beautiful Orange Beach, AL.

So...I replaced the needle valve and the metal cup/seat. I did the test again with an elevated fuel line, still seeing the fuel level drop, much slower now. The fuel still does not appear to be going into the engine though, I still don't see it passing in though the intake manifold, just seems to be holding in the bottom of the air filter housing.

At any rate, I reconnected the fuel line and drained the oil out. I left the oil drain plug out and I did not put fresh oil in yet. I'm going to let it sit a day or two and see if fuel drips out of the crankcase drain opening, then I'll know for sure if fuel is going into the crankcase. If the fuel is holding in the the air filter housing then we'll see where it's going to go. Perhaps the air filter housing has to fill to a certain level before the fuel will then drain into the intake manifold and through to the crankcase. I can loosen the intake manifold bolts and see if that's happened.

I'm going back to that solenoid. If that solenoid is supposed to send a plunger up into that center opening to stop it up whent the engine is off then that might explain how the fuel is getting past the needle valve.

Can someone tell me what should happen if I can remove that solenoid from the bowl but leave the wires connected? Does that solenoid operate, as in continuously on/off/on/off while the engine is running, or is that solenoid in one position while the engine is on and then another when it is off? If that is the case, can I remove the solenoid from the bowl but leave it connected and then turn the ignition key on, should I see a change in the solenoid position or does the position only change when the engine is actually running?

 

[arch252]

Did a little more research a la You Tube, pretty confident at this point that I have a faulty fuel shutoff solenoid. I'll test it in the morning and see if the solenoid is bad or if there is a wiring problem. Thanks for those who attempted to help!