Help with Carb Issues

troops159

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Hello, I am hoping you guys can give me a hand..

I'm trying to help out a friend to get his mower running.. He has a Simplicity 38" rider with a Briggs and Stratton 356777 engine. He was having trouble with it staying running so I cleaned the carb for him (just a cleaning, no carb kit). It then ran fine for 10-15 min before I left his place. While I was there I noticed that the inline fuel filter would only fill up about 1/4 of the way when it was running (full if it sat off for a while). Now it'll sputter, blow smoke and die. He had somebody else look at it and they told him that it wasn't getting enough fuel. They checked the lines and determined that the fuel pump was bad, so he replaced that. Now he says that it still sputters, blows smoke and dies but also blows fuel into the air filter through the brass hole in the upper left corner of the attached photo. He said that when this hole is plugged with your finger, it runs much better..

He lives about an hour away and with my work schedule, I can't get there for a few days. I am also not sure where this brass hole leads to or what it does.. Any ideas what is going on, what this hole is for and what you think the issue with the mower could be??

Thank you

T2YA1bo.jpg
 

Rivets

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Willing to bet you will find a bad head gasket. Try this remove the spark plug wire on one side and see if it will start. Repeat on the other side. If the engine will run, or run better, on one cylinder and not on the other you’ve found the problem. The cylinder which runs best is the good cylinder. The plug on the bad cylinder will be carbon and oily.
 

troops159

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thanks, i'll have him give that a try tomorrow
 
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Hey Troops .............

That fuel filter being not full while running is normal...... But the smoke and sputtering is not normal.... I do agree with Rivets about a head gasket.....

You or your buddy need to check the oil and make sure it's not MAKING oil..... Such as a head gasket that's blown or a leaky needle and seat in the carb...... Depending on what carb you have on there.......

I really can't tell from the picture you posted.... Can you or your buddy take another pic ?? A lil further out for a better view.. He can send you one in a text and then you can post it.......

As for as the engine running with a finger on the brass hole... That means something is not right in the carb itself..... Like I said another pic would help a lot.........

Let us know Mon Ami ~!~!
 

Rivets

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That brass hole is probably the crankcase vent and if so, the engine will run slightly better when plugged for a short period of time, due to more back pressure. This is another indicator of a possible blown gasket, not a carb problem.
 

troops159

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Here is a photo that shows the port I am talking about.. Not his actual carb but I believe it is the same model. Port I'm talking about is circled. If I remember correctly, when I was cleaning it, I think this port leads to the bowl (maybe a vent or overflow?)

O3anGmj.jpg
 

Rivets

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I’ve reread your posts and can’t see where you mentioned anything about a port, before your last post. I honestly have no idea where the hole you’ve circled goes to, could be the bowl vent. Small engine carbs have no overflow tubes. I don’t understand why you are fixated on the carb, you original post description has the signs of a blown head gasket on one side. As I said earlier, that hole in the air cleaner base is a crankcase breather or vent and has nothing to do with the carb.
 

troops159

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Thanks for the suggestions everybody. It appears we have figured out the issue and it was a bad float. Turns out it was sinking and letting way too much fuel into the carb, causing the fuel to blow out the port that I was talking about.
 
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