Briggs 16HP Vanguard carb / fuel problem

[Forest#2]

I've never seen anything like that carb as being a Walbro.. (in the USA and your engine model number is USA strange. Make sure you do not have a intake manifold air leak. The chole and throttle is slightly different on the USA LMT Walbro's.
Can you post up the complete Model, type and code of your engine?
Dopes it say Briggs on the engine or ????

 

[Wurzel]

Am now wondering what it is! It looks like a Vanguard, but is branded John Deere, code plate below and Briggs plate from the other side also pictured.

Will check manifold leak with carb spray but it's pretty snug. I'm struggling with it running flat out on choke, evidently getting enough fuel, then dying when the choke restriction is removed. It actually smells rich the whole time to me but that doesn't make sense.

 

[Wurzel]

Video showing choke effect:

 

[slomo]

It has a fuel mixture screw which I've checked

THAT is the pilot either fuel or air screw. In THAT circuit, sounds as it's clogged. You mentioned half a turn to 3 turns, does nothing. That told me it was not working as it should. REMOVE the pilot screw. Spray carb cleaner in there. Spray compressed air in there. Rod the hole out with fishing line or bread tie. Try to seal the hole with your air nozzle to really force the clog out. Research welch plugs on carbs. You might need to remove one or more to get BEHIND them to get the carb clean.

When I do try to rev without choke the carb chucks fuel forward out of the air side and kills the engine straight away.

What does the flywheel key look like? Are the valves set proper? Remember there are 2 TDC strokes on a 4 cycle engine. Could be set on the wrong stroke. Flywheel key needs to be unmolested and aligned straight up, perfectly. CLEAN the block cooling fins while you are there.

Can't take a pic of float height as bowl would be on? Or have I misunderstood? Float is on in the above pic but I can turn it over and support it at closed level if that's what you mean?

YES, your 3rd picture from the left. Now flip the carb upside down. Look at the float and the mounting surface for the bowl. Float should be parallel to the bowl mounting area. Not hang below nor above.

Starting to think it might be easier to find an aftermarket carb and hope it works - grass is growing!

Easy does it there. Try and get this one going.

 

[slomo]

That is a Briggs engine.

Parts Lookup

shop.briggsandstratton.com

Carb is no longer available per Jacks Small Engines.

Some of the others here might can find a superseded carb part number??????

 

[slomo]

Make sure you have full battery voltage AT the carb solenoid wires, key on. That thing "could" be limiting fuel flow into the carb, could be sticking. I always snip those plungers off so as to never have a fuel delivery issue again.

 

[Forest#2]

Did you look on the top of BOTH valve covers for complete engine info?

sometimes someone will install a valve cover up side down and the info is not visible.

Also if you decide to remove the welch plugs as a final attempt for good cleaning/rodding of the passages, I've removed welch plugs and re-used the same ones by very carefully drilling a tiny hole in the center, I use a drill stop so as to drill through only the welch plug, then I can carefully pull it out with a o ring pick or a awl then re-form the welch plug on a piece of leather and to seal the hole I have some slow drying two part epoxy that I use AFTER the welch plug is re-installed on the carb. My epoxy is the consistency of majarine or soft butter and will not flow through the hole and I coat the complete welch plug out to it's edges and smooth it out with finger before it completely dries. It's actually Brownells acraglass gel.
Do as slomo says about using high volume compressed air. That is type carb that high pressure air can be used with no concerns about damaging the internals the internals. I sometimes place screen wire cage around a carb before injecting high pressure air so as to catch welch plug if they blow out and become lost.

Here is a link that shows two different carbs and parts list for a 303777 1147-E1
The latter cab 807639 and it's parts kit 807962 is very expensive type.

The earlier 808728 is more reasonable one but they go by engine code numbers for the two different carbs.

https://jackssmallengines.com/jacks...arburetor-fuel-supply-kit-carburetor-overhaul

 

[Wurzel]

THAT is the pilot either fuel or air screw. In THAT circuit, sounds as it's clogged. You mentioned half a turn to 3 turns, does nothing. That told me it was not working as it should. REMOVE the pilot screw. Spray carb cleaner in there. Spray compressed air in there. Rod the hole out with fishing line or bread tie. Try to seal the hole with your air nozzle to really force the clog out. Research welch plugs on carbs. You might need to remove one or more to get BEHIND them to get the carb clean.

I haven't fired compressed air through there yet but it has had a load of carb cleaner through. I'll also try compressed air in case the carb cleaner hasn't moved something, plus a wire guitar string I've found works well. I've pictured the fuel screw port in the venturi below, what do those three just visible (hard to get phone to focus!) behind do? They're connected to 72 in the diagram via a channel (showing in pic 1 top of carb) in the carb body - again all blasted through with carb cleaner and apparently clear.

The fuel screw was doing little previously, but now if I lean it off too much it stalls, so is working at the least in part.

Flywheel - haven't got in that far yet, will check and also do fins if clogged. Valve clearances likewise.

Will also check float level. Disconnecting the solenoid kills the engine, but I'll check the voltage to see if constant. I'm twisting the carb once it's off the engine to unscrew the bowl, as I can't see a way to easily disconnect the solenoid wiring at the solenoid. Twisting the solenoid will have twisted the wire and stressed the connection over time / previous owners I'm sure.

@Forest#2 was there info missing from my last? I will check tomorrow in daylight again. Noted re welch plugs, thanks for the tip!

Appreciate your continued help!

 

[Forest#2]

Just to give you a brief idea of their use:
Those ports in the carb throat are called something like transistion ports.
You can re-view such on-line. One is located on the air intake throat above the butterfly of the carb and its the idle port. Air rushing through the throat sucks gas through which ever port the butterfly has opened towards. On the high speed port below the butterfly or engine side when the butterfly is wide open all three will be providing gas by the suction of air rushing past the port/ports.
One of the other two is on the engine side of the butterfly and it's the High speed port that sucks more gas into the engine as the butterfly opens.
The one in the middle might be a trasistion between the high and low butterfly opening.
They all have to be open and yes hard to get to. You have to be careful and not break off a wire in them or you will be SOL. No way of getting the wire/rod back out. One goes to the idle circuit and meets up with others channels under a welch plug. The metering circuits and jets are located inside the carb to regulate the proper amount of gas coming out those posts per the butterfly opening amount and jets sized per HP of the engine, etc. Do not damage those ports.
A hint where this idle welch plug is is it's usually close to the idle jet area if the carb has a adjustable idle jet. I have some long different size needle tips that I can put on my air nozzle gun so as to blow high pressure air back through those ports. The air nozzle kit I have came with a air nozzle and about 6 different screw on tips. It looks similar to this one.

https://www.amazon.com/Connection-Compressor-Accessories-Inflation-Dedusting/dp/B09BMXFV3L/ref=sr_1_3?keywords=air%2Bnozzle%2Btips&qid=1681171293&sr=8-3&th=1

 

[slomo]

Make sure you have full battery voltage AT the carb solenoid wires, key on. That thing "could" be limiting fuel flow into the carb, could be sticking. I always snip those plungers off so as to never have a fuel delivery issue again.