I have a 21" Craftsman push lawn mower v a Briggs and also Stratton 7 hp engine that is about 6 years old. I"ve acquired it cutting on the highest possible setting, and also it still has worries cutting the grass there is no loosing rpms in the thicker locations of the lawn. I"ve excellent 0 maintence come it besides putting some oil in the this year because it looked low, and also actually getting the blades sharpened (that aided immensely), but I quiet feel choose it need to be powering through the gas an ext than the does. What are some measures I have the right to take to enhance the power / cutting capacity of my lawn mower?

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request Apr 4 "12 in ~ 14:41

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Changing the Spark Plug and Air Filter are good ideas, and also are general maintenance items. The carbohydrate cleaner could additionally be sprayed into the carb v the intake.

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If those items dont gain back power, over there is a great chance your motor"s compression is low - and also you need to rebuild it. That can be anything from new gaskets come needing device work done.

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answered Apr 5 "12 at 20:58

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I created this post on my forum (yes, selfless plug) about two year ago. Its location is referred to as Hot Rodding her Lawn Mower. I think it is pertinent and will define after I write-up the article:

I, like countless of you, have a more recent self-propelled lawnmower which has a collection engine speed. Girlfriend grab the safety handle, pull the starter cord, the point goes vroom, you relax the cable and it shuts off. You perform not have any direct method to change engine speed. One of two people it is on and also running, or off and also not. The various other day I had actually an worry with the engine wherein it didn"t seem to be running up at its normal speed. I began looking at how the carb and also all was placed together to check out if there was something wrong. What I established turned the end to be an easy problem come fix.

Looking at just how most lawnmower engine rate is controlled, the comes down to 2 things. First, over there is a little vane form lever which is associated to the throttle on the carburetor. The cooling fan which is on top of the engine, blows waiting on this vane together the engine speeds up, actually causing the butterfly in the carbohydrate to close, slowing under the engine. What causes the engine to speed up is the second part of the equation, i m sorry is a small spring, which pulls versus the vane. It ends up being a simple tug that war in between the spring and the vane, which permits the engine to operate at a continuous speed.

Basic output of any kind of engine is computed by using torque output and also engine speed and running it through an equation come come up through a horsepower number (NOTE: view below). There space two means to rise the horsepower: boost the talk at any given engine rate or by boosting the engine speed itself (the second works to a allude where the torque worth decreases to a point where there are diminishing return ... Yet that is for one more discussion). On a little engine as I explain above, the easiest method to rise horsepower is by accelerating the engine. You can speed increase the engine of this kind by either putting a stiffer/shorter spring on to pull versus the vane OR you have the right to lengthen the street the existing spring has to pull ~ above the vane. The contrary is what had actually happened to mine lawnmower. Specifics the little metal mountain which the feather hangs off of had actually been bent towards the carburetor simply a tiny bit. This was resulted in by something hitting it during mowing. I took a driver (any long prying device will work) and also gently bent the metal mount far from the carb. This allowed the engine to speed ago up to its common running speed. Reasoning if a small was good, an ext would it is in better! Letting the "Tim The Toolman Taylor" in me come out, i bent it simply a wee little bit more. This make the engine operation a tiny bit much faster than it to be designed. As described above, this boosts the horsepower calculation of the engine and permits me to run through deeper grass an ext easily.

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The factor why this is necessary is this: I found on my own lawnmower that I had actually inadvertently bumped the item which stop the spring, thus shortening the spring"s hold distance, allowing the mower to operation at a reduced rpm and not structure enough rate or HP come power v the difficult grass. A lawn mower with a 7hp engine should have actually no problems powering through also deep grass. There is much more going on, I"d think, than just tuning.