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I Decided that since we don't have one of these I would make one. I figure someone out there will find it useful. If nothing more it's something to look at.
In this thread I'll be posting write ups and how tos related to small engines. I'll also be posting various small engine related tips, tricks, technical information, and anything else I find interesting. I may also post non small engine related stuff from time to time.
If you have any small engine related questions this is the place to ask them.
In case anyone is wondering what qualifies as a small engine, it's basically anything that isn't a car,truck,large tractor or otherwise big engine, usually 2 cylinders or less. This includes lawn mowers, weedeaters, edgers, atvs, riding mowers ect.
If you have something you want to see a write up for just ask. I'll be covering certain items as I get them but some topics I can cover with what I have laying around.
Here is some of the kinds of stuff I'll be posting. There's going to be alot of pictures in here.



Pressure washer pump:

How to fix The Lt 1000s poor hood bracket design:


Backfire solenoids (one was cut up by a PO)

Fs 6 and Fs 10 ac compressor teardowns: (click the picture)

 

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Enjoy my
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Discussion Starter #4
Briggs and Stratton quantum Carburetor Cleaning

Starting out with something simple, though that's mainly because I'm working on stuff as I get it. Please excuse the very zoomed in pictures and dirty mower. My garage is a mess and a bit cramped right now and its a bit cold to be breaking out the pressure washer. critique welcome.

Just yesterday I acquired this mower:

It's a Toro Super Recycler, not to be confused with the regular Recycler series mowers.
The standard Recycler series has a steel deck with single speed front or rear wheel drive and a Briggs and Stratton, Tecumseh, or Kohler engine.
Here is a newer Recycler series mower:

The super Recycler series Has an aluminum deck, Briggs and stratton or Kawasaki engine, and 3 speed Rear wheel drive. It's a heavier duty commercial style mower. This one happens to be in great shape.
Now for the main topic, the 5.5hp Briggs and Stratton quantum engine. The PO told me he had it running 2 months ago but now wouldn't start. Modern Gas is terrible, 2 months is plenty of time for it to varnish and cause problems. I already knew It needed a carburetor cleaning, but to double check the easiest method is to remove the air filter, then spray some carb cleaner or starting fluid into the intake and try to start it. It should start then die, If it does then there is a fuel issue. Luckily The quantum series engines aren't picky when it comes to carburetors, so they're easy to clean, The method I used can save a bit of time. Anyway enough talk here's some pics.
The air filter cover comes off with one screw, then you should see this.

There are 3 bolts holding the filter housing on. Keep in mind that once you remove this housing there is a gasket that will likely tear and have to be replaced.

With the air filter housing out of the way you can get a good look at the carburetor.You can see the gasket I mentioned has torn. Now is a good time to clamp the fuel line shut.

Grab a 1/2" socket and ratchet or wrench to unbolt the main jet.

Once you start to loosen the main jet any remaining fuel in the bowl will dribble out. Be ready for it.

Here's a shot with the bowl and main jet removed. Note the sediment in the bowl.

Heres a closer look at the main jet. The main metering orifice is at the top, with two fuel feed holes at either side on the bottom. This is The ONLY jet in this carburetor, and the simplicity of the design is why the carburetor can stay attached to the engine.

A piece of wire from a wire wheel works well to clean the jet. The passages in the main jet must be clear or the engine won't even try to start.


After clearing and major blockages in the jet, use a compressed air nozzle to remove any remaining debris.


A razor blade makes quick work of the remaining gasket.

Gasket removed. Use the air nozzle to clear any visible passages in the carburetor, there are two in the intake, the venturi tube that the main jet screws into, and the primer, which is the small hole under the left bolt hole.

Bowl and main jet reinstalled. There is a O ring for the bowl and a gasket on the main jet but unless they are damaged or leaking they can be reused. Unless you pulled it off the O- ring will probably be stuck to the carburetor body.
You can test run the engine at this point if you choose. carb cleaner or starting fluid will have to be sprayed into the intake to get it to start since the primer isn't installed.

This is the new air filter housing gasket. I have a bag of these on hand because they almost always tear.

Here's how the Gasket goes on, there are locating pins to help line it up and hold it on during installation.

Air filter housing reinstalled. Tighten the 2 bolts that go into the carburetor first, then the other one. Now is a good time to test the primer. Push the primer bulb a few times and you should see fuel spray into the intake of the carburetor.

This mower was getting a full tune up anyway, so I topped it off with a new air filter. I like to coat the mating surface with a bit of grease or oil to enshure a good seal.


After this the engine still wouldn't start so I drained the water contaminated gas and put some fresh stuff in. It started and ran great.


I had the cover off to check a cable and thought I'd post this for anyone who ever wondered how a self propelled mower works. This particular mower, although 3 speed, works on the same principle as most do. The gearbox pivots on it's output axle. When the self propel is disengaged the box rotates forward and the belt is slack.

When the self propel is engaged the box is rotated rearward, pulling the belt tight and driving the gearbox.

Most self propelled mowers use this type of design weather they're front or rear wheel drive. Some have a clutch built into the gearbox which engages as well, but many do not.
 

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USAF C-17 Maintenance
'94, '92, '88, and '84 Broncos
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I have a super pro recycler from 1993 that is a cast deck, and a five horse OHV motor with no brand markings other than Toro cast into the side of the block. Always wondered what company put the motor together. Never had it apart and still starts like a champ.

Adrianspeeder
 

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Discussion Starter #6
I have a super pro recycler from 1993 that is a cast deck, and a five horse OHV motor with no brand markings other than Toro cast into the side of the block. Always wondered what company put the motor together. Never had it apart and still starts like a champ.

Adrianspeeder
One of the first mowers I ever fixed was just like that. Should be a kawasaki, they're a big name on commercial mowers.
 

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USAF C-17 Maintenance
'94, '92, '88, and '84 Broncos
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My ole man bought it new back in the day. I used it heavy and hard back in high school when I full time cut grass, and use it for my back yard nowadays where I can't fit my big mowers through the gate. Hell, the rear wheels are worn down to slicks, and I might have to finally spend money on 'er for some new ones.

Adrianspeeder
 

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Discussion Starter #8
My ole man bought it new back in the day. I used it heavy and hard back in high school when I full time cut grass, and use it for my back yard nowadays where I can't fit my big mowers through the gate. Hell, the rear wheels are worn down to slicks, and I might have to finally spend money on 'er for some new ones.

Adrianspeeder
I did some reading, what little I found points to it being a Briggs and Stratton engine, but not a very common design.
All the rear wheel drive mowers have issues with the tires wearing out. Usually runs around 30-40$ for new rear wheels depending on brand. Home depot carries the newer Recycler wheels in stock but I don't know if they'll fit the older style mower.
 

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Anything small engine related? Now this is a small engine...

 

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Discussion Starter #10
I've been wanting to post more but I'm waiting for parts to come. in the meantime I thought I'd share this.



If you've ever tried to move a riding mower that doesn't run you probably know how much of a pain it is, especially if it's a hydro. So I made this tow bar.
Normally I pull mowers forward, but this is how I handle a stubborn hydro that doesn't like to freewheel:

 

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My parts finally came in so I can get some more stuff done.
This is what I was working on today, an Echo string trimmer.

I know it's not pretty. When I got it the gas was bad and it had carburetor issues. It sat for a while, I used the gas tank as an emergency replacement for my edger, then it sat in this state until now.

It's getting a Carburetor rebuild, new fuel lines, and a new air filter assembly.

I don't actually know what the model is, the stickers with the model and serial numbers are missing. luckily the carburetor has the model numbers on it.
Here's the carburetor along with the rebuild kit. This carburetor is a Zama RB k75, The rebuild kit is RB-123. This one of the most common carburetors on Echo equipment. If you have an Echo with a rotary valve style carburetor it's probably one of these or some variation of it.

We'll start here. The primer bulb normally goes here, but I stole it for something else. Remove the 4 screws and the primer bulb and plate come out.

Remove the single screw holding the fuel pump/primer assembly.

Fuel pump/primer assembly removed. Note the brass mixture screw at the bottom of the carburetor. This is normally covered by a plastic cap. The fact that it's missing means someone has attempted to correct carburetor issues in the past.

Use a pick to carefully remove the filter screen.

Everything removed from this portion.

Now for the fuel metering section.
Remove the two screws and pull off the metal cover. The diaphragm should come off with it.

Diaphragm and cover plate removed. The fuel metering needle is visible.

A single screw holds in the needle assembly.

On to the throttle assembly. There are 4 screws holding this plastic assembly on, 3 on top and 1 on the side.

Carefully slide The Throttle assembly out of the carburetor
There is a small roller that can be easily lost.

A closer picture. You can see the roller more clearly. It sits on a pin and once the throttle assembly is removed There is nothing to keep it in.

With the Roller removed the carburetor is ready to be cleaned. I threw mine in an ultrasonic cleaner but you can soak it or blow the passages out with compressed air. Don't use compressed air or harsh chemicals on the plastic fuel pump/primer assembly, it has small rubber valves that can be easily damaged.

Once your carburetor is clean open up your rebuild kit. Find the new roller. Dab a finger in some grease and use it to pick up the roller. Place the roller on it's pin, don't worry about cleaning the grease up, It won't hurt the engine and the fuel will wash it out anyway.

I like to coat the throttle assembly in grease to enshure a good seal and help lubrication.

Throttle assembly reinstalled. To test it rotate the throttle open slowly. the throttle lever should rise as it is opened.

Now for the difficult part of this job, the fuel needle assembly. The kit comes with all new parts for this. I like to place the needle, pivot, and lever into position, then use a pick to get the spring into place. Reuse The screw to hold it in.

This one actually wasn't too bad, normally they give me all sorts of trouble.

Place the new diaphragm and gasket onto the cover plate. It goes in this order : cover > diaphragm > gasket > carburetor
Make shure the diaphragm is facing the way shown.


Back to the fuel pump/primer assembly.
Place the new filter screen over its spot then carefully push it down with a pick.


Place the new fuel pump diaphragm and gasket on the fuel pump/primer body.
The order is: pump/primer body> gasket > diaphragm >carburetor.

Hold the fuel pump/primer assembly and place the carburetor on top, then install the single screw. This will keep the diaphragm/gasket from coming out of place.

You can reuse the primer bulb so long as it's not stiff,cracked, leaking, or on another carburetor. Otherwise replace it.


Here's all the parts that were replaced. Note the crack in the fuel metering diaphragm.

Carburetor, choke housing, new gasket ready to install. There is no gasket between the choke housing and the carburetor so I coat the mating surface with grease to keep dust out.

Carburetor reinstalled.

This trimmer is also getting new fuel lines and an air filter assembly. One of the nice things about Echos is that parts are readily available. I picked up a fuel system kit and air filter kit locally for less than ordering it. The fuel system kit came with new fuel lines, gas cap seal, and primer bulb.
Fuel system kit# 90127
Air cleaner kit# 90112

Here's what the new fuel lines look like. You can replace just the lines and reuse the filter, vent, and grommet.However this trimmer was missing all of those.

A little grease helps to get the grommet into the tank. It may require some persuasion with a small screwdriver.

Everything Reassembled, ready to run. The fuel pickup line connects to the larger of the two ports on the carburetor.
When you pump the primer bulb fuel should enter the carburetor through the filter and return to the tank through the short clear line.



Carburetor Adjustment:
Remember that mixture screw I mentioned earlier? You should adjust it as part of the rebuild. Here is the mixture screw when everything is assembled.

It can be adjusted with a small screwdriver.
-Start by turning it in until it bottoms out, then turn it out 1 1/2 turns. This should allow the engine to start.
-Start the engine and warm it up.
-Hold the engine at WOT and adjust the mixture screw until the engine runs the fastest.
-When you find the spot where the engine runs fastest, turn the screw counterclockwise a little to richen the mixture. This will provide a bit of safety so the engine doesn't go lean and starve of oil.
-Don't turn the screw too far out. Plenty of engines will run very well at base setting and need little if any adjustment.

This engine now starts easily and runs great.

Thought I'd leave off with a few unrelated small engine pictures.

These came in the other day. I'll be installing Them soon and covering that as well.


The side effect of continuing to run an engine after the carburetor leaks tons of gasoline into the crankcase, blows the head gasket, washes out the bore and starts burning oil like crazy.


The inside of a 16.5 hp OHV Briggs and Stratton.
 

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Discussion Starter #14
Is that carb job pretty much the same for a Stihl FS45?
And thanks for the thread.Great idea.:thumbup
Alot of Stihl equipment, including the fs45, Uses the butterfly style Zama carburetors. They use a different design with 2 mixture screws. Despite the design differences, replacing the diaphragms and needle is very similar, but adjustment is completely different. These have 2 mixture screws, one for high speed and one for low speed. This design is actually more flexible as far as adjustment, but getting it dialed in can be tricky. I'll see about doing an adjustment write up.
 

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I had a whole bunch of stuff that I pulled off the racing mower forums when I was building my parallel twin mudding mower I'll see if I can find and add it here
 

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Remember The picture of brake pads I posted earlier?
Here's what they're for. A 2006 Suzuki Ozark.

The brakes were making noise and were down to bare metal so I ordered a set of pads. Lets dive right in. pop the wheel off and you'll be looking at this. It will probably be alot dirtier though, I had to wheel mine out and hose the dirt off.

Turn the handlebars to get better access to the brake caliper. Remove the two mounting bolts holding the caliper bracket to the knuckle and pull the caliper from the rotor. It may be a bit stubborn and need to be pried off.

Being that this is a machine specifically designed to go through dirt, mud, and water, many of these parts are quite dirty. Normally I would clean all of these but since they will just get dirty again I'm only going to worry about the contact points.

Remove the two slider bolts and the brake pads.

Use a C clamp and one of the old pads to slowly compress the piston back into the caliper.

If your sliders move freely then you can probably skip this part, but I did it just to be shure. Use a pick to remove this rubber cap, exposing the slider.

Unbolt the slider from the bracket. It will stay in it's bore during this. You may need to temporarily reattach the caliper to the knuckle to break it loose.

Here it is unbolted. Don't lose the washer.

The caliper bracket can be removed with the other slider still attached. Just rotate it until it clears the caliper and pull it straight out.

Carefully use a pick to pull the slider's boot over the end then push it out the back of it's bore.


Both sliders removed. The smaller slider can be left on the bracket if you prefer.

Clean the old grease from the sliders and apply new grease. I'm using disc brake grease.

The small slider installs from the front and the large one from the back. Make shure the slider boots are seated in their grooves.

Caliper bracket reattached. Don't forget the rubber cap for the large slider.

Find the brake pad shim from your old pad and place it on the new primary pad. A little white lithium grease from a spray can doesn't hurt, Just don't get it on the pad material.

Spray any contact points as well as the slider pins with grease then install the new pads and bolt in the slider pins. The pad with the shim should be contacting the piston.

Slide the caliper back over the rotor and bolt it down. It's a good idea to clean the rotor first.

Pop the wheel back on and pump the brakes a few times to seat the pads.
Here's a shot of the old pads, they're all down to bare metal. Suprisingly the brakes still worked well, they'll work much better now though.
 

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I f*cking love this thread. Small engines have always been an interest of mine, lots of fun to tinker with and most are pretty simple. But I'm a cheapass, I rinse them out with carb cleaner to get them running before I worry about rebuilding them. I've brought several back to life with just a rinse, then a Seafoam rich mixture of fresh gas. Basically free resurrection. If they don't run after that (or shit looks REALLY nasty, like the diaphragms) then I'll get a kit.
 

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I f*cking love this thread. Small engines have always been an interest of mine, lots of fun to tinker with and most are pretty simple. But I'm a cheapass, I rinse them out with carb cleaner to get them running before I worry about rebuilding them. I've brought several back to life with just a rinse, then a Seafoam rich mixture of fresh gas. Basically free resurrection. If they don't run after that (or shit looks REALLY nasty, like the diaphragms) then I'll get a kit.
I use to be like that but now I don't even take them apart until I have the kit. I don't like doing things twice so if it's coming apart it gets new diaphragms. I'd rather do it once and know it will work than risk having to take it apart again. I'm also doing more of these though.

I didn't post this last night because I was tired and my eyes were sore by the time I finished the brake pad write up.
A piece of the Final drive has been a bit loose ever since we got it and after draining what looked like chocolate pudding from the gearbox I decided to do some investigating.

This was actually alot easier than it looks.

Here's the part I was talking about. Suzuki calls it the coupler or joint. Whatever it's called its loose and flops around.

I knew it would need a new coupler so I wasn't worried about damaging it.
I ended up welding a piece of metal to the shaft and wailing on it with a hammer to get it out (its supposed to just pop right out.)
Here's what It looked like once the coupler was out. Nice to see the gear oil I just put in already looks like pudding.

Here's the problem. The splines are actually sharp because they are so worn. This allows the coupler to move around too much and since the seal rides on the coupler it can let water into the gearbox. There's supposed to be another seal between the coupler and the driveshaft but it was missing when we got it.This is likely the source of the problem, as it allows dirt, sand, water and everything else to get into the splines and wear them out. This is actually a common problem on the ozarks but most people run them until they stop moving and by then the bearings in the gearbox are gone.

Here's another shot with the seal removed. Luckily the gearbox is still pretty tight and the splines on the driveshaft and pinion are still in good shape. So it need a new coupler, coupler seal, oil seal, and a ton of gear oil. Still better than a new gearbox.
 

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Cool thread

This one has a 26cc 2-stroke, stroked out to a 27.2 with some port work and a billet crank case, lightened flywheel, walbro 990 race carb, and of course a tuned pipe. Runs great. I will try to get some more pictures of it in action the next time I have it out racing
 

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Discussion Starter #20
Cool thread

This one has a 26cc 2-stroke, stroked out to a 27.2 with some port work and a billet crank case, lightened flywheel, walbro 990 race carb, and of course a tuned pipe. Runs great. I will try to get some more pictures of it in action the next time I have it out racing
Where the heck do you race something like that?

A couple random pictures.
Briggs and Stratton Quantum piston damage.

5-6 hp B&S Quantum in the front, 6.5 Tecumseh in the back.

A few years ago I had a 10hp B&S engine seize unexpectedly during starting. The cylinder was scored so I replaced it with another engine and threw it on a shelf. Recently I decided to tear it down and see what was going on. This is what I found.
 
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