OK, so I feel like I have tried everything. I was recently gifted a used Ariens self propelled mower, manufactured in 2005, with a Briggs and Stratton 6.75 Intex OHV engine. When I got it, I put some fuel into it and was able to get it started. It ran for a few minutes, the idle speed dropped, and it eventually cut out. Since then, nothing. It sputters, but I cannot get it to completely start. I have replaced the carburetor, made sure it is getting a good supply of new clean gas, checked the air filter, replaced the spark plug and checked for spark, checked the timing and flywheel key, and changed the oil. The compression seem to be decent, though I do not have a compression kit to officially test. When I try to start, it sputters a little bit and very small amounts of white smoke puff froth the muffler. Even when spraying starter fluid into the spark plug chamber,it will not start. I am at my wits end and want to get it running. It all seems to be clean, clear of debris and in good shape does anyone have any ideas? Thanks!
Cannot get mower to start...what now?
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reynoldston
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Fuel, spark, compression, timing and it will run. You are missing something. Are you getting a good 1/4 inch of spark? You need a good compression gage to check compression. You replaced the carburetor with what, new, used? Are you getting a good supply of gas to the carb. ? Timing isn't something that will change unless the flywheel key is bad. Keep looking I am sure you will find something.
Thanks for the reply. I am getting good, clean fuel to the carb. the carb I put in what a new, B&S replacement. The flywheel key is good. Not sure what you mean when you say 1/4 inch spark...the gap isn't that big, so I am missing something there. The compression seems good, but again, I do not have a gage to test it. That may have to be my next test... Any other thoughts? Thanks again!
reynoldston
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What I mean by a good 1/4 inch of spark is. They make a spark tester that is adjustable and you need to get a good 1/4 inch of spark jump. This will tell you that you have a good healthy coil or not. What I have done in the pass is take a old junk spark plug and open the gap to a 1/4 inch or more. I also have a tester to check if there is spark when the plug is under compression which is also needed. Tools of the trade that is needed in a repair shop. You can buy these tools at most auto parts store for very few $'s.
bertsmobile1
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It is harder for a spark to jump a gap inside the cylinder under compression than it is to jump outside the engine in air.
Roughly 1/4 " outside the engine = .040 " inside the engine.
There was an old plug tester which we connected to a compressor and a trembler coil .
You increased the pressure inside till the spark went out to test the plug.
bertsmobile1
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And you have missed Valve lash.
With the rocker cover off & plug out rotate the engine slowly and watch the valves.
They should go in & out evenly , smoothly and both sit at the same height above the floor of the head.
If one is in further than the other then the guides have moved and the head is toast.
If one moves in a jerky motion, the stem is bent or a build up of carbon is making it stick.
If the gap is too big the decompression will not work, if the gap is too small the cylinder will not get enough fuel in to start and then the exhaust opens before the charge has burned.
With the rocker cover off & plug out rotate the engine slowly and watch the valves.
They should go in & out evenly , smoothly and both sit at the same height above the floor of the head.
If one is in further than the other then the guides have moved and the head is toast.
If one moves in a jerky motion, the stem is bent or a build up of carbon is making it stick.
If the gap is too big the decompression will not work, if the gap is too small the cylinder will not get enough fuel in to start and then the exhaust opens before the charge has burned.