Vanguard 12.5HP/14HP/16HP/18HP carburetor cleaning

[MattA]

My 4016 with 16HP Vanguard engine has been surging more and more recently mostly at idle but I can hear it a little at full throttle. I pulled the air filter assembly off, removed the carb top and did a basic cleaning. I found the jet had some crud in the end which I was able to blow out. I took a bunch of pictures for a how-to but then I discovered a better video on youtube. I used a can of CRC carb cleaner and I recommend safety glasses and a rag over the carb when spraying into passages (cleaner can spray back in your face).
Vanguard 12.5HP, 14HP & 16HP all use the same bottom end with a different carb. The 18HP and 20HP (no longer marketed) have a bit more displacement but appear to have a similar carb setup. The 23HP and possibly the 21HP use a two barrel carb and have even more displacement.
Fully removing the carb on the on 12.5HP, 14HP & 16HP (possibly 18HP?) require disconnecting the stub shaft from the flywheel, unbolting the engine from the frame and sliding it forward to remove the various shrouds. I'm not sure whats required on 21HP & 23HP vanguards.

[MattA]

I'm still having trouble with the engine surging. After mowing the lawn, the surging was back especially at idle. I made a second attempt at cleaning the carb. More junk in the pilot jet. Also cleaned out the bowl. Ran good at first while towing the fertilizer spreader around but the surging came back again.
I'm going to clean the carb a third time. I may pick up another kind of carb cleaner and I plan to blow the pilot get out with compressed air this time.
My gas isn't that old. Since the initial carb cleaning, I've refilled my 5 gallon gas can and burned through about 3 gallons. I've also been running seafoam with the new gas (about 1oz to a gallon).

[DavidBarkey]

I'm still having trouble with the engine surging. After mowing the lawn, the surging was back especially at idle. I made a second attempt at cleaning the carb. More junk in the pilot jet. Also cleaned out the bowl. Ran good at first while towing the fertilizer spreader around but the surging came back again.
I'm going to clean the carb a third time. I may pick up another kind of carb cleaner and I plan to blow the pilot get out with compressed air this time.
My gas isn't that old. Since the initial carb cleaning, I've refilled my 5 gallon gas can and burned through about 3 gallons. I've also been running seafoam with the new gas (about 1oz to a gallon).

Can you describ the junk you are getting out of the carb? In therory with a good filter nothing should get into the carb but gas . That being said , we all know how ethanhol(water absorber) and additives in the fuel break down and create a vasilene looking sludge before creating corrotion . Is the the junk black ? If so I would say you need to change fuel lines and or fuel pump as they are breaking down inside . I have had issue with a few filter recently not actually sealed inside let debrie past . The carb is obviously the source of the surging , but where is the junk coming from is the million $ question.
Once you get it sorted out , drop your mix of seafoam to 2 oz per 5 gallon for maintaining fuel.

[MattA]

I'm still having trouble with the engine surging. After mowing the lawn, the surging was back especially at idle. I made a second attempt at cleaning the carb. More junk in the pilot jet. Also cleaned out the bowl. Ran good at first while towing the fertilizer spreader around but the surging came back again.
I'm going to clean the carb a third time. I may pick up another kind of carb cleaner and I plan to blow the pilot get out with compressed air this time.
My gas isn't that old. Since the initial carb cleaning, I've refilled my 5 gallon gas can and burned through about 3 gallons. I've also been running seafoam with the new gas (about 1oz to a gallon).

Can you describ the junk you are getting out of the carb? In therory with a good filter nothing should get into the carb but gas . That being said , we all know how ethanhol(water absorber) and additives in the fuel break down and create a vasilene looking sludge before creating corrotion . Is the the junk black ? If so I would say you need to change fuel lines and or fuel pump as they are breaking down inside . I have had issue with a few filter recently not actually sealed inside let debrie past . The carb is obviously the source of the surging , but where is the junk coming from is the million $ question.
Once you get it sorted out , drop your mix of seafoam to 2 oz per 5 gallon for maintaining fuel.

Inside the carb looks decently clean. I did remove the gas and remove what little brownish red sediment I found. I'm thinking I'm not getting the pilot jet fully cleaned out. The hole in the end of the pilot jet is partially clogged when I clean it and when I'm done I can see though it. I'm thinking of using some compressed air to help clean it out. Maybe soak it in some cleaner. I do have a new OEM fuel filter to put on it. Fuel pump was new last year or the year before. Changing the fuel pump didn't change anything in the past so I kept the old one. The fuel line between the carb and fuel pump and between the fuel pump and valve cover were replaced ~6 years ago. Not sure if I replaced the fuel filter to fuel pump section but I have more fuel hose. The tank to fuel filter hose has not been replaced.

[MattA]

Adding a picture from my phone. This was before I cleaned the carb, first attempt. Little bit of crap in the bottom left by the fuel shutoff solenoid.

From the pictures on my phone it looks like I cleaned the carb in 2019 and 2016. I think it was 2019 that I pulled the engine to remove the carb for cleaning. Engine ran good afterwards.

This was in 2016 after I bought the tractor. It was a snowblower tractor only and had been sitting. The owner had passed away.

[Eugen]

You could get junk from the tank or along the fuel line, which disintegrates with time. Long term fix is to replace the fuel line and clean/coat the tank (if metal). Short term fix is a filter.

Another thing to consider is maybe an air leak?

[MattA]

You could get junk from the tank or along the fuel line, which disintegrates with time. Long term fix is to replace the fuel line and clean/coat the tank (if metal). Short term fix is a filter.

Another thing to consider is maybe an air leak?

The modern fuel tanks are plastic. Fuel filter is up front between the steering tower and the engine.

Most forum topics and videos point to the carb. I ran into one that said repeated carb cleanings didn't help, the problem was the governor adjustment. The service manual says to fix the carb before adjusting the governor. I did check the governor arm adjustment but not the stops yet. Thanks for the air leak idea.

[MattA]

Well I got about an hour of free time tonight. Pilot jet was again plugged. I stuck a piece of stripped 26AWG? solid core wire though the pilot jet several times and nothing came out. Didn't seem to clear the end hole out either. Compressed air shot backwards through the jet cleared the end hole out. I also shot some crc carb cleaner through the pilot jet a few times letting the jet sit between cleaning attempts. I also shot compressed air down the pilot jet hole. The last thing I did was drain the fuel tank through the existing filter and install a new filter. The old filter had plenty of flow. Maybe a quart or so per minute. It's raining and the kids are asleep. I'll run it in a few days when I mow the lawn.

[Eugen]

Well I got about an hour of free time tonight. Pilot jet was again plugged. I stuck a piece of stripped 26AWG? solid core wire though the pilot jet several times and nothing came out. Didn't seem to clear the end hole out either. Compressed air shot backwards through the jet cleared the end hole out. I also shot some crc carb cleaner through the pilot jet a few times letting the jet sit between cleaning attempts. I also shot compressed air down the pilot jet hole. The last thing I did was drain the fuel tank through the existing filter and install a new filter. The old filter had plenty of flow. Maybe a quart or so per minute. It's raining and the kids are asleep. I'll run it in a few days when I mow the lawn.

Well, I'm confused though, by the source of material which plugs the jet . What do you think?

[JSinMO]

Well I got about an hour of free time tonight. Pilot jet was again plugged. I stuck a piece of stripped 26AWG? solid core wire though the pilot jet several times and nothing came out. Didn't seem to clear the end hole out either. Compressed air shot backwards through the jet cleared the end hole out. I also shot some crc carb cleaner through the pilot jet a few times letting the jet sit between cleaning attempts. I also shot compressed air down the pilot jet hole. The last thing I did was drain the fuel tank through the existing filter and install a new filter. The old filter had plenty of flow. Maybe a quart or so per minute. It's raining and the kids are asleep. I'll run it in a few days when I mow the lawn.

Well, I'm confused though, by the source of material which plugs the jet . What do you think?

I was thinking the same thing. It’s a plus for sure that your able to see the problem and clean the main jet but there seems to be an inordinate amount of junk getting into the carburetor. I was thinking it might be worth pumping some gas into a clean container to see what’s in it. I realize this has a plastic gas tank but there still could be junk in it.
The filter had good flow but it’s possible it’s letting junk through as well.

Just some things that came to mind as I was reading. I’m interested to see what you find.