# HS 720AM Carburetor Problem



## seusden (Feb 5, 2017)

I have and Honda HS 720AM that had a sizable fuel leak from somewhere in the carburetor. It leaked a bit when the not running and the fuel valve was turned on and a ton when running. 

I opened up the carb and bit, cleaned off the gaskets, and scooped a bunch of gunk out of the carburetor bowl. 

Now the fuel leak is gone, but after it runs for half a minute there is a pretty good oil leak out the hole pictured. 

When I pulled the oil dipstick to check the level oil gushed out even the the snowblower was level. Also the whole time the engine will only start when the choke is off. 

Any suggestions on where to look next are appreciated.
Photo: https://drive.google.com/file/d/0B3x3xN2b0DRNcmZqYWdFamxCU3c/view?usp=sharing


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## RIT333 (Feb 6, 2014)

Do not run your machine with all of that oil/gas mixed in the engine, or you can hydro-lock the engine. Be sure to drain the oil, and re-fill with new oil before using, and after fixing the carb.


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## JLawrence08648 (Jan 15, 2017)

I agree with RIT333 completely, do not try to run the engine until the oil is drained completely, again, completely. Then refill to the proper dipstick level. I would also remove the carb and take it apart and look for white residues and such. Look at the carb gasket that it's not twisted or turned or compressed too much. Clean the needle valve with very fine steel wool. I would go through all the holes with a set of welding torch tip cleaners. Consider draining the gas tank and hoses completely.


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## skutflut (Oct 16, 2015)

You mentioned that the carb was full of gunk. It sounds like the gunk gummed up the float assembly, preventing it from rising up to close the needle valve, allowing gas to flow through the carb (not just leaking out the bowl) and into the intake manifold, leaking past the intake valve, and into the crank case.

You need to clean that carb *thoroughly,* including the needle valve and it's seat to make sure you are gunk free. Also clean the jets and all the other nooks and crannies you can find that gunk would have passed through on the way to the intake manifold. 

As mentioned by others, drain the crankcase which is now full (overfilled) of gas mixed with oil. Refill with clean oil. If it were me, I would run it for half an hour or so, then change the oil again to get all the gas residue out of there, because gas is a great solvent for oil.

One of the reasons all the owners manuals tell you to check the oil before using the machine every time you use it is to check for HIGH level as well as LOW level. 

Whenever you find you have HIGH oil level, you can be pretty sure you also have a carb problem, unless of course, you overfilled the oil, but since we all check the level carefully during the oil change routine, leaving the thing with too much oil in it is a pretty rare occurrence. 

Chances are that the engine will start and run OK after you do whats needed, but you might possibly have some problems down the road with leaks depending on how long the crankcase was full of gas/oil mix. Not the end of the world, can all be fixed, but keeping an eye on levels, and maybe get into the habit of turning off the fuel valve and letting the engine stop by running it out of gas might help prevent the same thing from happening again in future. It also prevents having the garage stinking of gas from the leak.  Also, make sure your gas is reasonably fresh and add stabilizer to the can before you fill it up at the gas station.


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## seusden (Feb 5, 2017)

Thanks for the pointers. I drained the gas/oil, did an actually good job cleaning the carburetorm and it works great. 

Cheers,


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