H starves for fuel ?

My 48 H starves for fuel after a few minutes at idle. I replaced the gas cap, cleaned the carb, replaced the sediment bowl assembly, added an inline fuel filter to see the flow, and even cut a small groove to allow the bowl to vent better. This last step was after weeks of messing with this. I would appreciate any advice. You guys are always wonderful, you have helped me really enjoy this hobby... and I do try to pass that on.

First
Tell us what you did to "Clean the carb"
Get rid of the inline fuel filter .!!! Gravity flow fuel filters will NOT work !
Check inside of fuel tank ?
Check float level in carb . or a piece of trash in inlet screen on carb .

If that fuel filter isn't for a gravity fed fuel system I would remove it. Then see if your engine idles better and has plenty of power under load. Have you opened the main power jet adjustment screw near the bottom of the carb? This will enrich your fuel mixture. My old Toro mower and Ward's garden tractor have this same feature. Hal

I cleaned the carb in our carb cleaner at the motorcycle shop where I work. I got a rebuild kit new needle and seat etc and installed that. The issue was before the filter, I did that to see the fuel flow. It is for gravity systems and fuel will flow freely through it when it is not hooked to the carb.

Remove that tube fitting where your gas line connects and look for a screen as Griff suggested. This is often overlooked when cleaning the carb. Hal

Sometimes all it takes is a little flake of dirt or scale in the jet that the cleaning didn't touch. Use a small piece of copper wire (telephone) and poke around in all the little holes and nooks and crannys. Soak it again and blow everything out with air.

Thanks. I have had that out and cleaned it. I have also cleaned the fuel lines. I can see light all the way through them. I thought I had a piece of trash that would move enough to stop flow. But that was not the case. This is a real mystery to me, it seems like such a simple system.

Fuel flow starts with the air getting into the tank vent in the cap, then the inlet to the sediment bowl in the tank, the screen in the bowl, the fuel shutoff on the exit from the bowl, the line, the screen at the carb fitting, the seat in the carb, and the needle/ float system. (I stop there because the engine runs for a minute then starves.) If the filter is for gravity feed it will be OK for now, if for a Motorcycle it might plug easily
Diagnosis:
Put the exit end of the filter into a tin can and turn on the valve. if it flows a pint and a half a minute or more it is OK.
If not try the test before the filter.
If it does flow well, do the same test at the carb fitting, there is a screen in the fitting and it is often catching rust flakes from the line.
If it flows freely and as above, try the same tactic at the bowl drain. If it flows well there, the carb is getting enough, and the issue might be in the internal passages.
If not pull the bowl off of the carb while still on the engine. the bowl must not touch the float either when no fuel is in the carb, or when it is floating. If it touches, it will be unable to float and shut off the fuel correctly, or closed too far and not let enough in.
Put the can under the float and turn on the fuel.
At this point a pint a minute (1/2 liter) is good.
if not, take the needle out and see if it will flow Without a needle as it should. If not pull the seat and clean the passage above the seat.
if so concentrate on the float and its mechanical action with the bowl. The tang of the float to the needle, and the float drop tabs.
Best of luck, Jim
Hold the can under it

I had a leaf in a gas tank that caused that...drove me nuts figuring that one out.

Wow! Thanks Janicholson. I will try this step by step process. I appreciate your help. After I go through these steps I will let you know the result.

You didn't mention the float -

Perhaps it's simply set too low and you're not getting enough gas into the bowl to run on.

I'd guess blockage myself at first too, but it sounds like you've got that pretty well covered.

I'd spend a little time with the float at this point.

Could be that you're actually "flooded" to begin with (relative to where your float wants your carb to be), but when the extra gas burns off and the float's doing its job, it's just not enough.

Those carbs flood easily, and it's common to try to fix them by bending the floats down to shut off earlier.

Explxin the "starves for fuel after a few minutes". Does is sputter, sputter, lose rpm and die? Have you tried pulling tyhe choke out when it starts to "starve"? Does the exhaust change color? Pull a plug right after it starves and tell us what it looks like.

Hold your hand over the throat of the carburetor while a helper makes an attempt to start the engine and see if you have good suction. Low suction usually means low intake manifold vacuum.
Hal