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Mower won't start

Posted by imamoron none (My Page) on
Wed, Jul 9, 14 at 2:27

I have a Scotts mower with a 16hp Kohler engine. It sat for a year when the starter gear broke. I have replaced the starter, as well as the spark plug, fuel lines and fuel filter. Removed and cleaned gas tank, and have fresh gas. Oil is clean an uncorrupted. It turns over but will not fire, not so much as a cough or a sputter. I have verified spark, and compression seems to be fine. I have pored gas down the carb but no change, have sprayed starter fluid(either) in the carb, no change. If I remove plug and turn over, I do not get any gas thrown out the spark plug hole. It seems the gas is not getting from the carb to the cylinder, and infact I just removed the intake manifold and gas pored out. Am I right that something is preventing fuel from entering the cylinder? And what might the cause be?


Follow-Up Postings:

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RE: Mower won't start

If you can remove the valve cover you can manually turn the flywheel and see if the valves are opening, mainly the intake valve. You may have broken a push rod or something.

You should also list the motor's model number so we know what we are dealing with.


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RE: Mower won't start

OP - also noticed you did not mention cleaning out/rebuilding carb? Best to remove Take plenty of before after pixs, soak in carb cleaner liquid overnite, probe all orifices with stiff brass small dia wire and magnifier to spot all small passageways - blow all out with compressed air - rebuild carb with new carb kit using fresh gaskets/seats.

old carb may have had dried up fuel inside,which turns to jel blocking new fuel to combustion chamber...


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RE: Mower won't start

optsyeagle and rcbe, thank you for your interest and responses. I have given some poor information in that I confused the motors on two of my mowers. The problem engine is in fact a Briggs and Stratton model #28N707 type 0162 01, I think it is17 hp. The rest of the post is accurate. I will pull the valve cover off this weekend, although not sure what that will tell me or what further service/repair that will facilitate. Thank you again for trying to help.


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RE: Mower won't start

Well the only way the gas will accumulate in the intake and not make it to the combustion chamber is if the intake valve is not opening. With the valve cover off, turn the flywheel by hand clockwise and observe the lower valve. Does it get pushed in after two full turns or not. If not investigate why. That is my thought.

If gas is accumulating in the intake manifold the other thought is that it is gas that is leaking past your inlet needle on the carb and flooding the motor, preventing it from starting. I would think that you would see that gas blow out the spark plug hole but perhaps not. To test the flooding, if you can clamp off the fuel line from the gas tank, remove the spark plug and crank it 10 to 15 times to blow out as much liquid fuel as possible. Then put the spark plug back in, open up the fuel line and try to start it as quickly as possible. If you get it to papump, then it was probably flooding. If you get it to start and it runs fine, then just install a manual fuel shut off valve between the fuel tank and fuel filter and use it for storage. If it starts and eventually floods out again, you would need to remove the carb and figure out why the inlet needle is not closing properly. Either a bad float or crud in and around the inlet needle.

Also, give the oil dip stick a sniff to see if you can detect the smell of gas. Usually a leaking inlet needle will allow gas into the crankcase. If you do confirm flooding you should definitely change the oil.


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RE: Mower won't start

Alrighty then ... Removed the valve cover and the diagnosis was easy, rocker arm broken in half. How difficult will this be to replace?


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