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I'm trying to find a repair manual for the B&S 21R7070039 engine on my Troy Built Series 26J Mini-Rider lawn tractor.

Specifically I need to remove and clean and reinstall the Nikki carburetor.

It appears that two nuts on long bolts hold the carburetor body to the plastic intake manifold.

There is a gravity feed fuel line on the right side of the the carburetor body held in position by a spring clamp.

There is another line (a fuel return line or EGR line?) that goes into the front of the carburetor body.

There has to be a throttle line attachment and maybe a solenoid and wire connector for a solenoid at some location.

From the little I have been able to read (official service manuals - not reprints - of any kind seem hard to find on the internet), the gaskets, O-rings, etc., seem to be very finicky and non-reusable. That means that if you accidentally remove such a thing, you are obligated to buy the whole repair kit - not inexpensive.

The last time that I ran the lawn tractor it ran OK. However, even with SeaFoam gas treatment, after two years, the needles valves are probably stuck shut and gasoline carburetor cleaner does not seem to help.

That means that I probably have to get the carburetor off and at least get carburetor cleaner on the throat surfaces, or maybe soak the carburetor.

If I had an ultrasonic cleaner, I could just dunk it in the tank and let it run for several hours. But I don't. Mine broke some time ago.

So it's manual methods, and learning as much as possible before starting.

Also, is the float (assuming that there is one) hollow plastic, hard foam plastic, or metal? Some float types tend to get fuel logged and have to be/should be replaced.

I've also not dealt with a carburetor for a small engine that has - could have - a solenoid. What complications does that add?

So, back to the original, easier to take care of way to respond to this request: Where do I find a good, detailed service manual?

Thanks for any help.

Easiest way to do it is to remove the blower housing.
Take the air filter off & the housing lifts strait up leaving the air horn in place
Take a photo
You then undo the nuts that hold the air horn , pull the breather tube off the back & slide it forward
Take a photo
Now pull the plug out of the solenoid , there is no catch it just pulls strait off, but do not pull on the wires, a pair of pointy nose pliers is good for this.
Take a photo
Next is the studs that hold the carb body onto the manifold.
Take a photo
You will need a deep socket or a very short spanner for this .
Take a photo
Pull the carb back a little then rotate it and the choke rod will slip out of the slot in the control panel.
Take a photo
You then flip the carb to unhook the throttle rod
Take a photo
Finally move the crab to the right so the spring that will end up spearing your finger no matter what you do out of the throttle late on top of the carb.
The manifold can stay on the engine unless you want to replace the O ring which usually only gives trouble on very old engines .
Instructions on cleaning the carb are at out door power info

bertsmobile1 said:

Easiest way to do it is to remove the blower housing.
Take the air filter off & the housing lifts strait up leaving the air horn in place
Take a photo
You then undo the nuts that hold the air horn , pull the breather tube off the back & slide it forward
Take a photo
Now pull the plug out of the solenoid , there is no catch it just pulls strait off, but do not pull on the wires, a pair of pointy nose pliers is good for this.
Take a photo
Next is the studs that hold the carb body onto the manifold.
Take a photo
You will need a deep socket or a very short spanner for this .
Take a photo
Pull the carb back a little then rotate it and the choke rod will slip out of the slot in the control panel.
Take a photo
You then flip the carb to unhook the throttle rod
Take a photo
Finally move the crab to the right so the spring that will end up spearing your finger no matter what you do out of the throttle late on top of the carb.
The manifold can stay on the engine unless you want to replace the O ring which usually only gives trouble on very old engines .
Instructions on cleaning the carb are at out door power info

Click to expand...

I very much liked the final part . . . so the spring that will end up spearing your finger no matter what you do . . .

A fellow is not a mechanic unless he gets at least one skinned knuckle or bloodied finger.

I will plan to take photos and see if I can do a good writeup.

The photo is for you when you come to put it back together again.
The most common question we get is "where can I get the cheapest xyz "
The second one is "where does this bit go ?"

bertsmobile1 said:

The photo is for you when you come to put it back together again.
The most common question we get is "where can I get the cheapest xyz "
The second one is "where does this bit go ?"

Click to expand...

You may not get anything like that from me.

I thought about writing an illustrated instruction sheet on the procedure. I worked 14 years for AGCO doing technical writing on everything from windrowers to combines to big square balers and the electronic control systems. That's why I asked for manuals.

And if there are none, or I don't like them, I may still write and illustrate the procedure.

Best regards.

Briggs shop manuals are written from the standpoint that you are a trained mechanic with the knowledge to diagnose and work on something. So from a dealer standpoint they are a reference manual not the bible of repair procedures.

To remove those long studs you will need a deep well 5/16" (8mm) socket.

ILENGINE said:

Briggs shop manuals are written from the standpoint that you are a trained mechanic with the knowledge to diagnose and work on something. So from a dealer standpoint they are a reference manual not the bible of repair procedures.

Click to expand...

I needed the information, and didn't want to mess things up, so this is the forum where I asked my question.

StarTech said:

To remove those long studs you will need a deep well 5/16" (8mm) socket.

Click to expand...

Thank you for your help!

With regard to "where can I get the cheapest 'xyz'?" I try to buy the brand that made the machine. It usually turns out better.

wnlewis said:

With regard to "where can I get the cheapest 'xyz'?" I try to buy the brand that made the machine. It usually turns out better.

Click to expand...

As a self trained mechanic I have learned to pa attention on how things comes apart in order to re-assemble. When I use was a kid my self father would create all kinds of puzzles for me to work out. He even had rebuilding an Oldsmobile V8 head when I was only in the second grade. After which he checked my work and then installed the head. I do have the ability to disassemble, move things around, and assemble things in my head. Not all of us has this ability so taking pictures as you take things apart helps on reassembly.

In this case the service doesn't give step by step instructions for this removal.

Anyway take your time for at the first time around doing this job; meanwhile, I going out to tear down a 2014 Honda TRX500FE atv this morning. I havent done this model before so it probably take all day.to get the CV axles out for rebooting but first I got the replace a head on Sentar Kawasaki v twin engine.

bertsmobile1 said:

Easiest way to do it is to remove the blower housing.
Take the air filter off & the housing lifts strait up leaving the air horn in place
Take a photo
You then undo the nuts that hold the air horn , pull the breather tube off the back & slide it forward
Take a photo
Now pull the plug out of the solenoid , there is no catch it just pulls strait off, but do not pull on the wires, a pair of pointy nose pliers is good for this.
Take a photo
Next is the studs that hold the carb body onto the manifold.
Take a photo
You will need a deep socket or a very short spanner for this .
Take a photo
Pull the carb back a little then rotate it and the choke rod will slip out of the slot in the control panel.
Take a photo
You then flip the carb to unhook the throttle rod
Take a photo
Finally move the crab to the right so the spring that will end up spearing your finger no matter what you do out of the throttle late on top of the carb.
The manifold can stay on the engine unless you want to replace the O ring which usually only gives trouble on very old engines .
Instructions on cleaning the carb are at out door power info

Click to expand...

This guy owns stock in Kodak.

I have succesfully used a window fan laid on it's back across some scrap 2 x 4 s, put my can of carb cleaner, complete with carb right on top of the rig. Those cheap fans are never balanced and they will agitate the fluid very nicely. Works like a charm.

Joed756 said:

I have succesfully used a window fan laid on it's back across some scrap 2 x 4 s, put my can of carb cleaner, complete with carb right on top of the rig. Those cheap fans are never balanced and they will agitate the fluid very nicely. Works like a charm.

Click to expand...

So you are still using those hazardous chemicals I switched over to soap and water over 7 yrs ago and haven't looked back.

StarTech said:

As a self trained mechanic I have learned to pa attention on how things comes apart in order to re-assemble. When I use was a kid my self father would create all kinds of puzzles for me to work out. He even had rebuilding an Oldsmobile V8 head when I was only in the second grade. After which he checked my work and then installed the head. I do have the ability to disassemble, move things around, and assemble things in my head. Not all of us has this ability so taking pictures as you take things apart helps on reassembly.

In this case the service doesn't give step by step instructions for this removal.

Anyway take your time for at the first time around doing this job; meanwhile, I going out to tear down a 2014 Honda TRX500FE atv this morning. I havent done this model before so it probably take all day.to get the CV axles out for rebooting but first I got the replace a head on Sentar Kawasaki v twin engine.

Click to expand...

I do best with pictures and written instructions. So I will take the pictures and probably write instructions.

I don't have enough understanding yet to do the job without the "helps".

Joed756 said:

This guy owns stock in Kodak.

Click to expand...

Or is just really frustrated by people who tear something apart and then forget how they did it. And come yelling for help.

I have my old Kodak D2800 camera set up in the workshop over the top of the dissasembly bench.
It has a remote shutter release so with my dirty hands I can just push the button.
So the rule is photo of the whole tool
Photo of the part I just took off then photo of the toll again.
Thus when it comes to reassembly I have a photo manual

It is a really big PIA to try & tell some one where that mystery part they came across after finishing should have gone
Even worse as most point blank refuse to download the parts book so always use wrong names to confuse everyone even more .
Before I was doing this for a living it was easy because the bench was empty and I could lay the parts out in order on both sides over several feet but now it is not abnormal to be working on 20 tools at one time so that sort of space is a luxury I no longer have and when you grab a parts bin with a chain saw that has ben there for 5 months while you chased up impossible to find pats, one tends to forget exactly what order things go back together in .

Joed756 said:

I have succesfully used a window fan laid on it's back across some scrap 2 x 4 s, put my can of carb cleaner, complete with carb right on top of the rig. Those cheap fans are never balanced and they will agitate the fluid very nicely. Works like a charm.

Click to expand...

Sounds like that would work, but might give a person a bath in the cleaning solvent.

StarTech said:

So you are still using those hazardous chemicals I switched over to soap and water over 7 yrs ago and haven't looked back.

Click to expand...

I like the solvents, but only where they can be contained in a tank, or have a hood with an activated charcoal filter to deal with the chemicals.

Detergent and water will work very well, especially if the part is put in an ultrasonic cleaner. The only requirement is to dry everything carefully and blow out all the passages.

bertsmobile1 said:

I have my old Kodak D2800 camera set up in the workshop over the top of the dissasembly bench.
It has a remote shutter release so with my dirty hands I can just push the button.
So the rule is photo of the whole tool
Photo of the part I just took off then photo of the toll again.
Thus when it comes to reassembly I have a photo manual

It is a really big PIA to try & tell some one where that mystery part they came across after finishing should have gone
Even worse as most point blank refuse to download the parts book so always use wrong names to confuse everyone even more .
Before I was doing this for a living it was easy because the bench was empty and I could lay the parts out in order on both sides over several feet but now it is not abnormal to be working on 20 tools at one time so that sort of space is a luxury I no longer have and when you grab a parts bin with a chain saw that has ben there for 5 months while you chased up impossible to find pats, one tends to forget exactly what order things go back together in .

Click to expand...

It is indeed good to have photos and notes.

Without those memory jogs, it often becomes difficult or impossible to put something back together correctly.

StarTech said:

So you are still using those hazardous chemicals I switched over to soap and water over 7 yrs ago and haven't looked back.

Click to expand...

I've never used soap and water, but I'll give it a try, thanks.

Joed756 said:

I've never used soap and water, but I'll give it a try, thanks.

Click to expand...

It works great in the Ultrasonic cleaners. I just cleaned a two barrel Nikki today that looked like it had been in a pig pen. Now it looks like a brand new carburetor. I use A tablespoon of Daen Platinum in about 9 liters of water. Now of course I had to change it out to plain water for second run as the water was so dirty.