so I'm a total n00b when it comes to this stuff. I decided it might be important to be able to deal with problems of internal combustion engines and so I want to start getting a better understanding of them.

Up until now my understanding has been very cursory -- i know the basics of the 4 cycle engine, but not much beyond that. There are a lot of parts that I can't name and other things that I dont even know what they do.

I found a 4.0HP lawnmower on "big junk day" and brought it home with the intention of dissecting the engine. I assumed it would not be a working engine. Well I started it up after i got it home and it seemed to run fine. Great :) a 4HP 4stroke engine for free, with gas in it too.

But I still wanted to rip it apart, so I'm doing so. I wonder, will it work when I put it all back together again? Hahah .. well I'd like it to ... would eventually like to do something fun with it.

So I just wanted to ask a few questions about parts on this thing, help me identify what some things are.

Figure 1: I took this part off (circled) because I wanted to get the intake thingy off and it was in the way. What is this part i took off? It connects to the exhaust so my guess was a muffler. Is that right?

Figure 2: Actually the very first thing I did was to remove and drain the fuel tank. The fuel line hose looked a little worn and the clip things broke when I removed them. What are these clip things (circled) called?

Figure 3: I took a cover off because I wanted to see what was underneath. I knew it was something to do with valves. After taking this cover off i could see springs around the pole-like-part of the valves. First question: what is the cover I took off called? Second question, ( when taking the cover off i ripped this gasket ... oops). What is this ripped gasket (circled) called?. Last question ... what are the pole-like-part-of-the-valves that-have-springs-around-them called?

Figure 4: On the very top there is this bolt. I could not get it off. What is this bolt called, and what is the name for the piece that it is screwed on to? And how am I supposed to get this bolt off since it is on a part that rotates?

Figure 5: After failing to remove the bolt in figure 4, I thought I'd take the whole bottom part of the engine off. What is this whole-bottom-part called? Also, removing the 6 circled screws did not allow me to take this bottom piece off. Do I have to remove the big bolt on the top in order to do so?

Figure 6: I just would like to know at this point what these are. Guess for B is air intake. I have no guess for A.

Figure 7: This is related to figure 6 ... the circled item B is connected to what was circle A in figure 6. Just trying to get the names for these things. Also, circled item A in this figure 7 seems to be some kind of pump thing, my guess is for fuel. Is this the choke? Or what is this? Another thing, this whole "intake thingy" that the fuel line and carburetor are attached to, what is this part called?

Well if my lame ass questions have not put you to sleep yet I would most humbly appreciate the help with the names of the parts. Thanks kindly.

you have a tecumseh there, first picture is the muffler, second, the clips help to hold the gas line on, so not to slip off, which you don't want!. third the gasket is a breather gasket, which the breather is the valve cover as well, ( breather lets the internal pressure that builds up inside the crank case out ), 4th is the bowl, where the starter dogs catch onto, that nut holds that and the flywheel on., 5th picture, the bolts that are circled is the oil pan bolts, holds on the oil pan, the shaft out the middle is the bottom of the crank, then the second picture in 5 is the governor, and the third in 5, a is the primer bulb, that pulls gas up, that well primes the carb for easy fast starting, the other on is the throttle linkage and such. whats circled, as you may can see inside the carb, operates the butterfly, that lets in or cuts off air controlling fuel flow. oh and the plastic piece in the first one in number 5 is the drain plug, for draining the oil. oh and another thing about tecumsehs, unlike a briggs that can be basically put back together without doing much in the way of measuring, tecumsehs have tight clearances. oh and the ( pole-like-part-of-the-valves that-have-springs ) valve stems and valve springs.

Thanks a whole bunch bugman for helping me name these things.

Now I was wondering, is there a proper procedure to remove the big nut (in the bowl) off the shaft that runs up through the flywheel? I couldnt get it off because i was struggling to hold the flywheel in place while loosening the nut with my ratchet wrench, but i couldnt hold it.

And a followup, is it neccesseary to remove that nut on the top in order to get the oil pan off the bottom? I took the 6 oil pan bolts off but the oil pan didnt want to separate from the main engine block.

Thanks again! I think maybe I need to find a book or something! :)

There are special flywheel holders made for Briggs engines, but I've never seen one for a Tecumseh. You would probably just need to find a strap wrench big enough to fit around the flywheel. Hold the strap wrench in one hand to keep the flywheel from turning, and loosen the nut with the ratchet in the other hand (or get someone to help you). If the engine were mounted on a mower with the blade still attached, you could also use a blade holder to keep the crankshaft from turning while you loosened the nut.

The sump (oil pan) usually needs to be tapped off with a rubber mallet or something of that nature. You might want to wait until you get the flywheel off, though (so you don't have to deal with the dripping oil and the crankshaft hanging free at one end.) You'll probably rip the sump gasket when you pull it off and maybe the oil seal too, but it sounds like you already have a gasket or two that need replacing anyway.

i dont think i have ever seen a key ring used for a governor control as shown in fig 7-b that aint right lol