Almost hydro-locked from a fuel leak

D

DHook

Member
This is a Husqvarna YTH18542 riding mower. B&S 18.5 hp engine. 42" cut. Original owner. Bought new 8 or so years ago.
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Brought it out of storage this morning to do a mow, then changed the oil and other maintenance. While changing the oil, I smelled gas and could see gas dripping from the top of the carborator, down and all over the bowl. No drip from the supply lines. Definetly coming from the top of the carb. Tried to turn over the motor and it was stuck. Tried turning the flywheel by hand and could gear a gurgling noise coming from the air filter inlet. Shut off the gas supply and removed the top cover and the spark plug and fuel began leaking from the cylinder. Turned it over by hand and could see more fuel gushing out of the spark plug hole. Using the key, I turned it over a few revolutions to clear the cylinder. With the gas line still shut off, I replaced the spark plug and turned on the fuel again. It started reluctantly but once it started it ran normally. Shut it off and waited awhile to see if the leak reappeared and it did not. So thinking it was just a sticky needle or something, I reassembled everything and went to start it again and again it was stuck. Tried moving the fly wheel by hand and again could hear fuel gurgling in the cylinder. So cleared it out again, this time leaving the fuel shut off until I was ready to start it so I could move it so my wife could get her car out of the garage. So I moved it back to its storage place and am now trying to figure out my next step.

I was at first tempted to use the battery jumper on it, thinking the battery was a little flat for some reason (keep it on a tender over the winter) but probably a good think I didn't since the cylinder was full of fuel and I could've hydro-locked the engine and cracked the block.

I store the mower with an empty bowl, shutting off the fuel and letting the engine die. I always put in some gas treatment before running it dry. I bought it new and it's never had a whiff of ethanol fuel in it.

I know nothing about carbs so please, talk to me like I'm an idiot. Is there anything I can do to loosen up the sticky "whatever" without having to remove the carb all together? I'm deathly afraid of getting this thing taken apart and not being able to reassemble and make it run again. I posted a pic of the valve cover numbers so you can see what engine it has. Sorry it's sooo big. I might be willing to try putting in a rebuild kit if someone might know what kit it needs. I have the B&S parts manual and it lists a few different kits for different carbs. I'm guessing I would need to order this from B&S directly.

It's funny because I've rebuilt hydrostatic units on these mowers before and had no reluctance to tear into one but you give me a carb and I'm like a blithering idiot.

Thanks for any help.
 
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DHook said:
I know nothing about carbs so please, talk to me like I'm an idiot.
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LOVE IT...... We all had to start somewhere.
DHook said:
I smelled gas and could see gas dripping from the top of the carborator, down and all over the bowl. No drip from the supply lines. Definetly coming from the top of the carb. Tried to turn over the motor and it was stuck. Tried turning the flywheel by hand and could gear a gurgling noise coming from the air filter inlet.
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Sounds like the carb needle/seat is not sealing. Your home toilet operates the same way as it fills the tank bowl up.

Need to pull the carb and pressure test it to 7psi for 30+ minutes. Many videos on carb pressure testing on youtube.

Go look at your toilet tank. Fill valve is set to fill to a specific level per the person that set the valve up. When the fill valve in this case fails, it can and will over flow. This is what you are seeing on the mower carb.

FIX the carb before running the engine. Read what I said again. This leaking gas will get into the oil and dilute it to water like viscosity. Once the carb is confirmed fixed, dump the oil after each mow a few times.
 
DHook said:
I always put in some gas treatment before running it dry. I bought it new and it's never had a whiff of ethanol fuel in it.
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What brand of stabilizer do you buy? I use the original formula of Stabil. Get the smallest bottle and use it year round. It has I think a 2 year shelf life. If you are using outdated juice, I can see you having carb issues. Carb needle/seat sealing is not really a stabilizer issue. Leads us to the next paragraph.

My opinion is to leave treated fuel in the carb at all times. More important on 2 stroke trimmers and blowers with hoses and primers. Keeps the oil on the hoses and carb needles lubed up with 2 stroke oil. Also keeps your 4 stroke carb needle wet so as it doesn't dry the needle tip out and not seal. Some needle tips are metal and have a rubber seat.

I used to drain all my outdoor equipment over the winter. Noticed I had to replace carbs and hoses/fuel lines all the time. Started using Stabil year round. Stopped having to buy hoses and such. Always start on the first to second pull in spring.

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Thanks guys for the suggestions. Yes, used Stabil (couldn't think of the name of it when I was typing the original post. Damn this old-age thing!). And yes, I use it year round and usually add it to my fuel can when filling each time. I thought I was doing the right thing by letting the engine run dry of fuel but I see now that wasn't too smart. I'll leave fuel in the carb from now on and let Stabil do its' job.

The toilet bowl analogy is what I was thinking also. I guess my next step is to pull the carb off and try to open up the bowl first to check the needle seat. Hopefully won't have to go much deeper than that. I read stories about replacing the carb with cheap chinese crap and trying to avoid that. I think I have some time because it will be a couple weeks before I'll need to mow again so I can take my time with this project. Good tip on the oil change. Never thought of that. I'm sure it's already contaminated and diluted quite a bit.

Do I need to replace the gaskets when I remove the carb from the engine? Is there a number on the carb to look for to find the correct kit that would include new gaskets? Trying to figure out how to identify the carb to get the right kit because when I look at the B&S parts manual they show the exploded view of two different carbs and rebuild kits for them but they list two different carbs. One is a Nikki and the other is a
Ruixing. Not sure how to ID what I have. Any suggestions would be great!
 
DHook said:
I'll leave fuel in the carb from now on and let Stabil do its' job.
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Works for me. Doing this for over 7 years now, no issues.
DHook said:
I'll leave fuel in the carb from now on and let Stabil do its' job.
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Again works for me. Put Stabil in your main gas can EVERY can fill. This way if you fill say a small 2 stroke can, all your toys are treated.
DHook said:
I guess my next step is to pull the carb off and try to open up the bowl first to check the needle seat.
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Pressure test first with the carb off inverted then what you wrote. Need to confirm the needle is leaking then fix it if so. OEM carb rebuild kits or even Chinese fleabay/scamazon carbs, for the most part, will work. If going to fleabay, do NOT buy the cheapest listing you can find. Say the cheapest listing is 20 bucks. Get a 30 dollar listing. For me doing this I feel I get better parts with nearly zero issues. Used to get the cheapest listing for a carb that is no longer available. Had several I had to reset the float height and massage on a bit to work. Didn't run right out of the box. Needed a little tweaking to work proper.
DHook said:
Good tip on the oil change. Never thought of that. I'm sure it's already contaminated and diluted quite a bit.
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Definitely on the oil dumps. That is plural as you see.
DHook said:
Do I need to replace the gaskets when I remove the carb from the engine?
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If they tear or crack, yes. If it comes off clean, I would apply a THIN bead of Permatex Form-A-Gasket non hardening sealant. THIN as in THIN. Wipe it on with your finger thin.
DHook said:
One is a Nikki and the other is a
Ruixing
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If is says NIKKI on the outside of the body, I toss most of them. Just looked at your part list. THAT Nikki is a tosser in my book. Some guys on here have good luck rebuilding. I've bought OEM rebuild kits. They have a stamped out rubber o-ring like mess. Do the Nikki to Walbro swap, Briggs number 594593. Watch about it on youtube again. Several videos about it.
DHook said:
One is a Nikki and the other is a
Ruixing. Not sure how to ID what I have.
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Carb brand will be printed on the outside of the carb body.
 
TIP, clean the mower part of dirt and oil BEFORE opening the part up. So a valve cover, take a rag or old paint brush and dust off all the grit and trash BEFORE you remove the cover. Leaf blower, compressed shop air, tooth brushes and so on. Clean as in CLEAN. You do NOT want any grit or trash falling inside the engine. I keep an old paint brush in the tool box just for this.
 
Another tip. If you have an old gas can open top spout, get a new one. These have o-rings to better seal out water, grass, bugs, dirt, leaves and whatever. So open spouts get trash in the bottom of the can. Every time you fill up your mower, you pass all that trash to your carb. Tank can get plugged up. Carb doesn't run right and so on.

Middle can spout is preferred. Right spout, is wrong.
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I cleaned up around and on the carb and found the B&S name and the 592953 number. As you suggested, used small brush and air to remove dirt/grit. It wasn't too bad, considering. Took several pix of the linkage connection. Now just need to remove and check the float/needle/seating for leaks.
I looked at the B&S site for kits but it's quite a crap show to find anything on there so not sure where else to look. Maybe I'll try a local small engine mechanic and see if he could ordr one for me.

Thanks!
 
DHook said:
Took several pix of the linkage connection.
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SMART, thinking ahead.

This amazon carb, not OEM should work. They have OEM carbs too. I would contact the seller with your ENGINE numbers. Verify this will work.

Noticed the Briggs number has a lot of Nikki carb pictures listed as 594593. Maybe just the pictures on amazon? Briggs 594593 is a Walbro carb number. Walbro carb is the preferred one you want.

 
If you are careful taking it apart, you may be able to reuse the gaskets, needle and seat once the carb is cleaned. Look at some of the James Condon youtube if you need help knowing what to do. Jacks shows both Nikki and Ruixing as manufacturers of the carb for the 33R777-0003-G1 . Look at the parts pictorial and see which matches your carb. The carb kit numbers are on the page*. *The 594593 carb has several photos of it, showing it is perhaps a generic Briggs number, and perhaps a replacement for the original. One photo shows the solenoid on top, the other shows it on bottom. Both carbs are sitting the same direction and unfortuantely, both are labeled as Briggs 594593 OEM original. Post good photos of your carb if you want an opinion what it matches.


here are examples of Condon rebuilding Briggs carbs:


 
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