lawnmower - won't start, spills gas when pull starting


It's an old mower that was given to me. The cap says unleaded gas, the manual says four stroke, so I didn't use premix.
Tank was dry, I put in gas, when I yank the starter cord it's like I'm pulling against compression and gas squirts out the exhaust. Lots of it.
Sounds like it's dead and not revivable, but any idea what exactly is broken?
I admit, I don't know much about the insides of these things.
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TimR wrote:

Then it wouldn't do any good telling you anything.
--
Blattus Slafaly ? 3 :) 7/8

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Perhaps the float in the carburator is stuck open.
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replying to Bob F, Jesse Ramirez wrote: My push lawnmower won't start and shoot gas from the exhaust
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On 9/20/16 11:44 AM, Jesse Ramirez wrote:

Hi Jesse, as a certified lawnmower technician I have come across this problem many times in my line of work. The problem is that there is something wrong with your lawnmower.
Jon
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On 9/20/2016 10:49 AM, Jon Danniken wrote:

something that only a certified lawnmower technician can correct.
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Oren posted for all of us...

this leads to the question what kind of gas is being shot out the exhaust and what type of weapon is required to perform the operation.
--
Tekkie

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Oren posted for all of us...

is

s

t

Now I know...
--
Tekkie

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Oren posted for all of us...

I've been workn on the chain gang ~~~~~~~~~
--
Tekkie

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It's not dead, it just needs a simple carb repair. The float is stuck open or sunk or otherwise not closing so gas pours into the engine. Remove the carb, take it apart, clean, replace gaskets and maybe float/needle/seat as needed, put it back together. If you don't know how to do this, find a repair shop if the mower is worth the cost of repair. Maybe find a buddy that can do this? Otherwise, you might want to just get rid of it if it isn't worth what it would take to fix.
Fixing the carb is no guarantee there is nothing else wrong. You might spend a lot of money fixing the carb only to find the engine is blown.
Drain the gas tank. crank it a few times so there is no gas in the engine. Clean the plug, make sure it is clean and dry. Squirt some starter fluid into the carb and crank the engine a few times to see if it fires. It should start up and fire a dozen times or so and then die. If it won't fire with a clean plug and a squirt of starter fluid in the carb, there is something else wrong with it besides just the carb.
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TimR wrote:

Then spend some time learning. Come back and ask the question again after you've read the Time Life book on small engines and small engine repair, available at your local library. Maybe you'll have a glimmer of hope of understanding any solutions we give to you.
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Yes likely float stuck and now likely the oil is likely full of gas and soon the cilinder head. Get the gas out, if oil level is up , drain oil, and pull spark plug and crank it to see if gas shoots out. You can remove the carb bowl to see if the float moves up and down. Dont run it with gas in the oil, it wont lube. Before spending any money, now with the plug out check to see if you get spark by holding the plug wire 1/4" from the head with your hand and pull the starter cord. A minor shock will tell you its getting spark, pull the starter cord fast and hold tight.
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wrote:

Yes likely float stuck and now likely the oil is likely full of gas and soon the cilinder head. Get the gas out, if oil level is up , drain oil, and pull spark plug and crank it to see if gas shoots out. You can remove the carb bowl to see if the float moves up and down. Dont run it with gas in the oil, it wont lube. Before spending any money, now with the plug out check to see if you get spark by holding the plug wire 1/4" from the head with your hand and pull the starter cord. A minor shock will tell you its getting spark, pull the starter cord fast and hold tight.
Also, if it has a lever on the handle with a cable going to the engine, you need to squeeze it. It's an emergency stop.
Al
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Did that once. Must have been 19 years old. more than 40 years later, I say DON'T DO IT, IT HURTS!
Best to leave the plug lying on the head, you can see the spark.
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wrote:

Have a compression test performed on the engine. An exhaust valve stuck open would leak un-burnt fuel out the exhaust.
Pass that test, first.
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While the exhaust valve stuck open makes sense for the unburnt fuel to come out, does it also make sense that I'm pulling the cord against an all but locked engine? I can pull it slowly, as if compression is leaking down. Seems reasonable that if either valve were open I should be able to spin it easily.
I have taken one apart, but it was years ago, and at my age memory is unreliable. That one wouldn't start, but pulled easily, and when I got it open I found the circular piece that connects the bottom of the piston to the crankshaft had broken in pieces. I've also rebuilt several automotive carburetors, but they were even more decades ago.
A stuck carburetor float would account for the extra gas - would it also account for the heavy resistance? If so, it's worth taking apart to see. But if there are two separate things broken it's probably not worth the effort.
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