After several bad experiences I finally read on the Internet to not try and start a vertical shaft rotary mower engine without the blade tightly attached. The aluminum flywheel has insufficient momentum to get it over Top Dead Center and it WILL kick back and yank the cord violently. In my case I just ended up with a sore hand, elbow and wrist after several misfires. When I took the motor to the lawnmower shop the owner was as naive as I. When he pulled the cord, the handle was jerked from his hand and his fist hit his chest hard enough to knock the wind out of him. He was sitting on the floor in the corner for five minutes and then told me the engine was "unbalanced." I took it home and got on the Internet and discovered the true situation. I have a carb problem of "start and die" and your pages have excellent help. Thanks. Charles Crail.
I have a suggestion for all (sorry I could have not sent it in earlier, prior to Spring) ..
When purchasing a new lawn-mower, be it push, self-propelled, riding, etc., go to the local auto supply shop and pick up two or three cans of auto undercoating....(should cost about $10.00 for three cans) ...
Before putting gasoline or oil into the lawn mower, turn it over and spray the undercarriage with the undercoating...
Let it dry . .then apply a second coat ... and then a third... It is like a "tar" film, that completely covers the undercarriage and when cutting grass, rocks and other items that hit the undercarriage, do not chip away the paint.
I have done this to a lawn mower that I purchased over 12 years ago, and it has no rust on the chassis....
I also did this with a wheel barrow (before assembling it) that I purchased 5 years ago and likewise it has no signs of rust...
Back in 1991 I bought a mower with a briggs engine.
I put MOBILE '1' 10W -50 in the new engine.
This mower has been running like new ever since.
I change oil when it starts turning a little darker than the color of new oil.
Using the synthetic oil I have only had to change the oil once in 11 years.
For whatever reason the synthetic oil is keeping the carbon seepage for the combustion chamber to a minimum, and the oil stays cleaner long.
I just wanted to pass along this observation.
I just finished repairing my show thrower carburetor and here is some Readers Suggestions I discovered. Hope it is of some help to someone someday.
Tecumseh carburetor rebuild / after-rebuild tips for float-feed, adjustable, model # 750 types [and perhaps other models]:
I. INVISIBLE, NEARLY MICROSCOPIC, IDLE PORT: In the float bowl brass nut w/ main adjustment screw, in addition to the obvious inlet port [hole(s)] at the base of this nut, there is also an extremely small 'idle fuel transfer passage' in the annular groove [groove w/out threads] above the lower hole(s) and usually almost even with the edge of the lower thread of the annular groove. Without cleaning this area down to shiny brass and using a powerful magnifying glass in bright light [I had to use a jewelers eyepiece] you probably won't even see it. It invariably fills up w/junk and corrosion, and even if brushed, looks like it is only a dent from a prick punch. First, Soak the nut in carb cleaner or hot water and detergent or even oven cleaner. Neither an extremely small sewing needle nor a wire from a bread wrapper twist will penetrate this hole. I said a small prayer and it immediately came to my mind to cut off a wire bristle from a small wire brush [the kind that looks like a big toothbrush]. Wiggle the bristle into the hole w/ needle-nose pliers. After penetration, 'floss' it in and out w/ the bristle to remove the clumpy, dust-like material that has a hardness similar to chalk. Amazing how much this improves performance. Be sure to readjust the carb Main and Idle screws after this because previously it was running without this passage.
II. POST CARB-REBUILD ANTI-SPARKPLUG FOWLING TRICK: For older adjustable carbs, re-adjusting the main high speed, and idle mixture screws, the related over-rich, smoky flooding and stalls can quickly fowl the spark plug, especially a well used one. This only compounds the problem of starting the engine with an out-of -adjustment carb. If flooding fowls the plug, remove it, blow dry it w/ compressed air, clean it - and try warming the metal end before reinstalling it. This can give you a little more adjustment time before the plug refowls because the warmth evaporates fuel that collects on it, at least for a few more cranks. You may even have to do this several times before getting the carb into full adjustment.
III. QUICK FLOAT-SEAT CHECK: This may not be foolproof, but I tried it and it seems practical: With the carb inverted on the bench and a piece of flexible tubing connected to the carb inlet fitting and just the weight of the brass float holding the needle valve down, if you can blow air into it as you lift the float slightly but can't each time you let it down again, most likely, the valve and seat are working ok.