You know that bumper sticker you put on your old car, like 12 years ago, and has been cooked on to your fender for 12 years. It seems like that would be a permanent bond, but it's not. To liberate this old, cured adhesive is actually pretty easy. In this example I have a piece of aluminum that has a product label on it. I'm starting to surface finish the piece, and this label is in the way. It's been on there for around 13 years.
After refurbishing the original RX300 driver's seat, now I have an extra RX300 driver's seat. Originally I got this seat because the seat in the RX300 was worn out, and covered in duct tape. This link, RX300 Seat Renewed, covers the work I did on the original driver's seat in the RX300. This thread is about the spare seat that I used in the RX300 when I was working on the original seat. So, anyway, now I've got an extra RX300 driver's seat. I should do something with it...
So, my wife suggested that I get a new office chair at my desk. The old chair is 25 years old, and broken in many ways. It is so bad I don't want to publish a picture. So, like a lot of the stuff I build there needed to be some adaptation to use the RX300 Seat in the Office Seat role. It needs wheels, so I can roll around the house. I need the interface between the wheels, and the seat. Also, I need a theme to tie this automotive part into our home, and the office, so Fence Posts it is...
I want to do this cost effectively, and utilize the materials I have at hand as much as possible. In our home we have a lot of rustic furniture that it made from aged Cedar, and in order to tie this chair into the house I am going to use big hunks of aged Cedar. No, question there. So, I chopped up an old fence timber, and it will become the frame for the Office Chair.
Of course I want this platform to be very strong. The RX300 Seat is really heavy because it is a full power seat with five motor control systems. Sure, I could have got a light weight seat, and trimmed down the size of the base, but all at a cost. I wanted to use materials that I have at hand, but as few new parts as necessary.
But, I did have to get some new parts, all hardware. I used 3/8" x 6" Lag Screws to put the frame together. Then, I picked some 4" rubber casters on steel mounts, like you would find on a piece of equipment, or a big tool box. The heavy platform holds the seat well, and together they have the heft of a high quality chair, with an advanced level of comfort.
Next I needed to connect the seat to the platform. I like to use 1/2" hardware in my projects, so, that is the choice here as well. The size of the platform was dictated by the mounting pads on the seat, and I had to factor in the screw paths. All the hardware seems to fit alright.
The next task was to interface to the electrical controls. The motors that control the positions of the seat are all 12 Volt powered. So, I needed a wiring diagram for the RX300 seat. This took a little digging on the Interwebz, and resulted in a similar wiring diagram for a compatible seat.
The RX300 Seat has the motors that control the seat positions. and the switches that control the motors. So, in order to move the seats I needed to supply 12 Volts, and Ground to the right connections on the seat harness connector that goes to the body wiring harness. This was fairly simple, and I used a shop power supply to test the seat controls. My little bench top power supply provided enough current to run the Slide, and Tilt motors in the seat, but not the seat elevation. I also tried this with a 7 Amp Hour battery, and it was still deficient to run the elevation controls.
Oh look! It's another broken small gas engine. This one is special, well, sort of. It's a Briggs and Stratton Platinum Engine. It has overhead valves, which is still kinda new to me for an American made engine. Briggs and Stratton held on to the flat head design in the small lawn mower market right up until the turn of the Century, 1997. So, lets Rip into it...
Usually when I start debugging a small engine I want to try to start it. Then I can evaluate things like the ignition, and fuel system condition. On this one the Start Handle was missing. So, I guess we are going to trouble shoot the Starting System first. I removed the engine faring, exposing the Recoil Starter. Then I removed a few more screws, and the Recoil Starter is removed from the engine.
I disassembled the Recoil Starter assembly, and found damage. There is a keeper that holds the end of the recoil spring which is damaged, and it not holding the spring. This means the starter is not working, in multiple ways. The Pull Cord has been cut, the Pull Handle is missing, and the recoil spring keeper is damaged. This is an indication of long use. I was stuck here for a time looking for a part. But then realized that I have another mower with a very similar engine, and I could borrow the starter off the good working mower to test the broken mower. How fortuitous...
After swapping the Recoil Starter Assembly from the good working mower to the broken mower I was able to do a little more troubleshooting. The engine cranks, and I am reasonably sure that it is getting compression, and spark. When you pull the cord you can feel the compression stroke of the motor because the cord gets a little harder to pull periodically. You can hear the carburetor "whine" on the intake stroke, and you can hear the exhaust exhale on the exhaust stroke. This tells me that the rings, and bore are generally doing their job by making compression, and that the valves are sealing. I tested the spark by spraying some Carburetor Cleaner in the intake of the Carburetor, and cranking the engine. This resulted in the engine briefly running, and then shutting off.
With the testing I have done so far it looks like my Briggs and Stratton small engine has a fuel system problem. The fuel is not being metered properly into the engine, and the engine will not run because of this. The engine is not getting enough fuel to run. This mean we have to dis-assemble the carburetor, and see if we can find a problem. First there are two linkages we must disconnect from the carburetor.
Modern Mowers have automatic features that make the operation of the mower easier. In the picture above is a feature that engages the choke on the carburetor when the mower is cold. It is a thermal actuator connected to the muffler. Its function is to push the choke open when the mower warms up. For what we are doing here we need to remove this linkage from the carburetor so that we can remove the carburetor. So we need to remove three screws from the muffler heat shield, and two screws from the muffler, and then we can disconnect the linkage.
While you have these exterior pieces removed from the engine you can clean those spaces you would not normally have access to. Maintenance is largely about cleaning stuff, like the air filter, the fuel filter, and the little bits that get grimy...
The Air Cleaner Assembly holds the carburetor in place in conjunction with the bracket you see around the carburetor. The flow connection of the carburetor is a tube, with an O-Ring. I am beginning to like the simplicity here. Also, it is an all plastic carburetor, and is the first plastic carburetor I have worked on. It's kinda weird, but also makes sense to my engineering brain.
OK, now that the carburetor is detached we can get on with the task of determining our fuel system problem. At this point I have to note that I have not found a discrete fuel filter. Usually with lawn equipment you need a fuel filter because of the excessive amount of debris associated with lawn service. This mower does have a large, pleated air filter, but not a fuel filter. Maybe there is an inlet screen on the carburetor fuel inlet.
Small engines used for lawn mowers run at a single speed, and the carburetor can be simplified because of this. This carburetor is very basic. I think it still has idle, and run circuits, but I have to admit it is still a little mysterious to me. There are two screws to remove the float bowl, and then inside I found what appears to be a Jet Module which contains the metering jets for the idle, and run circuits.
There are three tubes on the Jet Module, and I think that two of them are the idle, and run circuits. Then I am assuming that the third is a vent, but I am not sure at this point. So, I am going to clean the Jet Module, and the Carburetor in general, and then re-assemble everything, and give it a Krank...
All the bits, and pieces go back together in reverse order, just like in the old car manuals, LOL! Easy right? No, really this is a very simple engine, and I think if we can get the Gas to the Bang Box itz gonna Krank...
I want to note some other features that I found on this fuel system. It has a Positive Crankcase Ventilation tube that runs from the crankcase to the air cleaner. There is a Gas Tank Vent that runs from the top of the gas tank to the air cleaner. Compared to other small engines I have worked on, this one has an oversized muffler. I wear headphones when mowing, so having less external noise is good.
I also want to note some things that are not on this engine. There is no Primer Bulb, which was once used to circulate fresh gas into the carburetor. Also this engine does not have a user accessible throttle adjustment. Old mowers had a throttle, and I guess these newer mowers use the governor to regulate engine speed. New mowers are more powerful, and less troublesome, I guess...
Well, looka there... I inspected the Jet Module carefully before I cleaned it, and it looks like the actual problem was there. Two of the jets looked open, but the one in the middle seemed clogged. After I sprayed with with the carburetor cleaner the "jet" in the middle opened up, and I got that warm, fuzzy feeling of success. The two jets on the ends have metal inserts, like they are used to precisely meter fuel, while the one in the middle was just plastic, and kinda seems to be a vent tube. I have to look into Briggs and Stratton Plastic Carburetors a little more. OK, Happy Mowing...
This prototype circuit is a good example of how my design process works. The point at which I built this prototype was in the middle of the design process, and not the starting point. The customer already had an electronic design, and wanted to have a Printed Circuit Board made. So, I replicated the electronic design with the circuit design tool I was using at the time (OrCAD). Then generated the Printed Circuit Board layout. Once we had released the Gerber files for fabrication is when I decided to prototype the design while we were waiting on the fabricated Printed Circuit Boards.
My main concern is that we got all the connections that needed to be made hooked up correctly. There was one enable pin that needed to be hooked up in order for the circuit to work properly. I was able to stop the PCB Fabrication House before they printed the PCB, and get the extra connection added. The Printed Circuit Board worked the first time once we had received, and assembled it.
The operation of the circuit works like this. First is the oscillator is a Quad Op Amp, LM324, which is configured as a relaxation oscillator. The LM324 has four Op Amps in it, so I used one for the relaxation oscillator, and the other three as buffer amplifiers. The clock signal is then fed to a digital counter, CD4024, a seven bit binary counter, which takes an incoming pulse train, the clock, and counts the number of pulses. The output is in binary, and there are seven output pins for the seven bits. The high order bits (4, 5, and 6) are fed to the sequencers address bits. The sequencer is a MC14051 Analog Multiplexor. The address input bits select which output channel get connected to the source. So, when you input address bits in binary order they will switch the outputs in numeric order, the sequence. This could also be an arbitrary selection if you were to use a processor to drive the address inputs.
Ethanol claims another victim. Small engines generally do not like Ethanol. Cheap pump gas usually contains 10% to 15% Ethanol. Ethanol eats the seals inside these small carburetors. So, if you use cheap pump gas, and leave it in your small equipment continuously then eventually you will have a fuel system breakdown, and have to repair your small gas powered equipment.
In this case it is a Stihl MM55C Tiller. It is a good Tiller, but I don't use it very often. Generally I use it a lot in the springtime, then it sits there the rest of the year. Well, I left fuel in it over that time. One springtime when I went to use the Tiller it wouldn't start, and wouldn't crank either. I try to pull the cord, and the motor wouldn't move at all. Well, it had a hydrostatic lock. There was liquid fuel in the combustion chamber, and it wouldn't let the piston move up. So, I pulled the Spark Plug out to relieve the pressure, and it spewed liquid fuel out of the Spark Plug port. Then I realized that a seal had failed in the carburetor, and was letting liquid fuel get into the engine. Big Puppy Sigh...
So, this is pretty typical of small engines. The equipment is kind of old, a few, or more years. I had been thinking that I had been using "good" gas, Super, 92 octane, but it still has Ethanol in it. Small Engine Manufacturers usually will have a compatible fuel available for their equipment. Stihl makes Ethanol Free 2 Cycle Fuel for their equipment. It is expensive, but is it worth the time, and energy needed to repair a damaged fuel system? So, the Carburetor is well gunked up due to use, and years of sitting. Well start pulling the fuel system apart.
Stihl makes small engines very well. They have a clean design, and are simplified as much as possible. They take service well, and I can get parts fairly easily. There were three screws in the back cover, one screw in the fuel tank, one screw in the air cleaner, and two nuts held the carburetor on. All the fuel lines are press fit, and there is some tricky part shapes that make everything fit together when the screws are in. It is refreshingly simple.
The Fuel Tank is pretty icky, as usual. I bought all the fuel system parts, so we'll be replacing the fuel lines, fuel filter, and the carburetor. Generally I like to get a rebuild kit that has all the replacement parts for the carburetor, but in this case the only option was a replacement carburetor.
The Fuel Tank itself needs to be cleaned, not just to get the gunk off the outside, but also to flush out the old gas inside, and any particulates that have got into the Fuel Tank. So the Fuel Tank get a full kitchen dish washing with soap, and hot water. We want to totally flush out the Fuel Tank, and then let it dry out completely before re-assembling the Fuel System.
Installing the new Carburetor is making my Small Engine look a little more complete. I salvaged the exterior gaskets from the old Carburetor. They seemed to be in marginal shape. I used a little more Silicon Spray when I installed the Fuel Lines on the Carburetor.
Once it was all back together I double check my work, then gassed it up, and gave it a krank. I spent a little time tuning the mixture screws, and my little MM55C is working again. Lets go rip some dirt...
In my FR-S, Ripper, the Cup Holder wound up in an unfortunate location. The Cup Holders are where the Arm Rest should be. They are right behind the shifter, and emergency brake, precisely in the path of my elbow when I am shifting into even gears. Yeah, I know there is limited space in the FR-S, and they had to do what they could to get a couple Cup Holders in there. But, yeah, not the best place. The Cup Holders work a lot better as Coin Cups, or maybe a Cup of Chile Con Queso, LOL!
So, what to do... What to do... Let's fabricate some auxiliary Cup Holders. Did you know that you can order Black PVC from Home Depot? You can get pipe, and sheets. So I wanted these auxiliary Cup Holders to accommodate all my needs, away from the center console. There are pockets in the doors that will hold a bottle, but not upright, so they need sealing lids. I usually carry water, and coffee, plus I need an ashtray. So, we need three holders. The diameters of the things I want to hold are all a little less than three inches. I picked three inch inside diameter black PVC Tube. Then to hold them all together I got a sheet of black PVC quarter inch thick.
The neat thing about PVC is that it can be glued together very effectively. This eliminates a lot of hardware that would have potentially been there. The PVC Tubes were cut to appropriate lengths for the things I wanted to hold, and then glued to part of the Sheet PVC. I had to angle the water bottle a little to clear the Glove Box Door. Then the PVC Sheet is connected to a center console panel with a couple machine screws. The center console panel then gets connected to the center console with snap clips, four of them, and it has a secure fit. This gets all of the things I want to hold out of the way of my elbow, yet still within a reasonable reach. The Cup Holders only protrude into the passenger space by about four inches, so, not too bad, LOL!
Being my first time to re-upholster a leather seat it took some time to figure out how this stuff works. In retrospect it's logical, and when the seat goes back together you get why all the things within the seat are the way they are. All the things within the seat work to make the finished look, feel, and functionality of the seat suit a need as a automotive seat. You have creature comfort factors, anti-fatigue factors, safety factors, and most important some would say, looks...
A luxury car is supposed to have good looking everything. The seats get scrutinized extra closely because you are in direct contact with them. Well, after my RX300 got used as a work truck for more than a decade the driver seat was looking terrible. The front passenger seat is not nearly so bad, and the back seats are hardly used because they are furled most of the time. So the big final task that I had with the drivers seat was to remove the seat back skin from the replacement seat. That means I had to totally disassemble another seat just to get the seat back skin.
I bought this replacement seat from a salvage yard to use in the RX300 while I was re-conditioning the original seat. This took a lot longer than I expected. So, above, is the replacement seat, disassembled, so that I could get the seat back skin. Doing this for the second time took considerably less time, now that I know the construction of this seat.
I pulled both the front seats out of the RX300 which gave me an opportunity to do some deep cleaning. I found a sub-woofer under the front passenger seat which I did not know was there. This RX300 has the Premium Sound. Having the seats removed allowed me to access a lot of areas I couldn't clean with the seats installed. The whole passenger compartment is a lot cleaner now.
This is the seat back heater. It is a lot simpler that the seat bottom heater. It was easier to remove from the old seat skin, and easier to apply to the new seat skin. It was a non-issue with the experience that I gleaned from re-upholstering the seat bottom. Re-installing the Hog Rings in the seat back was also a lot easier now that I had a little experience with it. Hog Rings work in a very specific way, and once you work with them a little you pick up their tricks.
This is one of my favorite features of the RX300 seat, above, the Lumbar Adjustment. Over the years I had imagined how the Lumbar Adjustment works, and this isn't what I was thinking. The way it does work is pretty logical. There is a gear reduction motor that drives a crossbar into the Lumbar area of the seat. When you push the control one way it drives this bar into your lower back, pushing the Lumbar Adjustment out. When you push the control the other way it drives the Lumbar Adjustment back into the seat. It is neat, and it is one of my favorite features of the RX300 seats.
OK, now the original seat is back in the RX300, with new leather seat skins, and it looks great. The seat heater, as well as all the electromechanical controls all work. The new seat bottom skin is a little off color, but that is a lot better that shredded seat skins covered with duct tape. Plus I got to deep clean most of the passenger compartment, so it feels a lot better inside the RX300 now...
