mower hard to start but runs great when started

My B&S powered mower has recently become very hard to start. In fact the only way I've been able to start it is by spraying some starting fluid into the cylinder. But once it is started it runs perfectly, no misses, no RPM drops, etc. I recently had to completely drain the fuel system as some water got into the tank but I've run a couple tanks worth of fresh gas through the system. I do think the beginning of the hard starting problem does correspond to the water in the fuel problem so I think it is related. But I've run out of ideas to try to eliminate the problem and would appreciate some suggestions from the group.
Thanks for any ideas.
John Keith snipped-for-privacy@juno.com
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If all else is well, it sounds like all you need a choke adjustment. Good luck
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Had the same problem. Inadvertently left the mower out in a rain storm and it would no longer start afterwards.
Poured the gasoline out, and let the tank dry for a day or two. Then filled the tank using a measured amount of "Dry Gas" or some such additive.
Pulled the cord and the mower started first time and has been starting on the first pull ever since.
The instructions on the can of additive say it will do no harm and in fact may be beneficial to use a measured amount of the additive every time the gas tank is filled.
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Also consider a vacuum leak. If your carb to gas tank gasket or the carb to intake gasket is leaking you could be pulling in enough air to make starting difficult but not enough that you notice it under full throttle.
Steve B.
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Update:
The gasket between the carb and the air cleaner was pretty much shot. This mower has a prime button and it appears the air channel for this mechanism is routed underneath this gasket and through a small hole in the gasket. It successfully started a couple of times yesterday and we'll see about today when I really need to use it.
After replacing this gasket and observing the primer button I got to wondering, mowers didn't use to have prime buttons and they started fine. Why did the manufacturers feel they needed to add that complicating factor?

John Keith snipped-for-privacy@juno.com
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Probably because too many people didn't know how to use a choke...
And it ended up being cheaper....
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Before the primer buttons became common, most small engines on mowers and similar equipment had a choke lever. One advantage of the primer button is that after starting, no furter action is required. With a choke, after starting the choke lever must be returned to the open position.
--

Larry Wasserman Baltimore, Maryland
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Thanks for the suggestions.
I did clean the air filter and the plug was serviced at the beginning of the season but I'll check it again. And I'll look at the gaskets.
BTW, I never saw my original post on this group. Is that some problem with my ISP?
John Keith snipped-for-privacy@juno.com
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I don't see anything about a clean spark plug with a proper gap.
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PaPaPeng wrote:

Nor leaning the air cleaner.
--
Joseph Meehan

Dia duit
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My Dad had (past tense) a generator with a 10 HP Tecumseh. It wouldn't start one time, having not been run in a couple years since the last power cut. A neighbor helpfully sprayed ether in the cylinder. The piston locked up, and the machine threw a connecting rod. Not a good idea.
The other folks have had good suggestions -- drain all the gas out, and dry it. Fresh gas. The other idea is to replace the gasket between the carb and the side of the motor.
--

Christopher A. Young
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