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Maybe got lucky on that start. It was on the intake stroke when you covered the intake. When it rolled over, it created a vacuum rather than sucking in air. Next, on the compression stroke, it had less air to compress because it pulled in much less air than it normally would. Next was combustion stroke - in this case just ever so slightly if at all compressed air was released, basically becoming negative pressure. Next came exhaust stroke... Exhaust valve open, engine free to breathe and pressure equalized. Intake valve opened again on intake stroke, started sucking in fuel but very little air (well choked). By now, the engine was probably spinning fast enough so the flywheel had enough momentum that the lack of compression release was a moot point and the engine started normally.

You may have actually confirmed a compression release problem.
 

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Discussion Starter #22
After I started by covering the intake I let it run for a good while. Then I let it cool and tried again a few times without covering the intake and it started right up with only a little hesitation pretty much as normal. The surging I was used to hearing at startup and low idle is gone too... perhaps because I adjusted the valves?
 

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Another thought although it would not affect operation of the starter is that there was a restriction of the idle circuit in the carburetor. When you covered the air intake it sucked (actually the higher air pressure of the atmosphere and blew) the restriction out of the restricted passage. This would explain why the engine does not surge anymore. That said i am still thinking as mentioned before that the compression release is not working due to "only a little hesitation" . As I said before remove the valve cover and turning the engine over by hand and slowly observe the lowest valve when the piston is at btdc and coming up on the compression stroke you should see enough movement to slightly open the valve it should do more than eliminate the valve setting clearance. If the only movement that happens is the exhaust valve opening after tdc the compression release in not working and needs to be repaired before the starting system is destroyed. By the way if that is the engine that I think it is the intake valve is on the bottom and it also does the compression release. Be careful when setting the valves as the Briggs singles are opposite than it would appear. I had a few folks who said the intake could not be the compression release but Briggs does use it for this engine. Don't believe me check the ports and where the valves are located. Also observe the operation of the valves when turning the engine over the correct direction.
 

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Discussion Starter #24
Same symptom came back after sitting for 6 hours and i covered the intake again and it fired right up. Steddy mentioned i might have gotten lucky though... does the fact it consistantly being started by choking it point to it being starved of gas.. ie the carb?

Of course i am tap dancing around removal of the engine. Im thinking i need to clean or replace carb and if it still happens then point to the cam release. Does that seem like logical?
 

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The carburetor sounds as if it is OK. If the choke is working properly then the only thing you are doing is stopping all air from entering the engine. No air no compression. The whole issue revolves back to the engine being able to turn over. If the engine will not turn over except when starving it for air or backing the engine up so the starter can get enough momentum to go over compression the compression release is not working. As I said before this is a common issue with these engines and if you have removed the valve cover and checked for the release to be working there is only one answer left. Most of the time pulling the engine is fairly easy UNLESS the pulleys won't come off easily. Then things can get very tough. I think Briggs has finally redesigned the compression release mechanism on the camshaft. While you are so close to the parts be sure to replace the gasket and the bottom seal. Just a bit of useless information to turn the engine over on full compression would take a starter of the size used on your car or truck
 

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Discussion Starter #26
Thanks i appreciate it. I didnt realize that i was removing compression by choking it. Looks like i will have to bite the bullet and remove it in the end.
 

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Discussion Starter #27
Is choking it to start like that bad for the engine?
How about running it with the broken release bouncing around in there?
 

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Discussion Starter #28
If i can hear air when spinning by hand and plug in, does that mean compression release is good?
 
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