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JohnF2015, Small Engine Technician
Category: Small Engine
Satisfied Customers: 1107
Experience:  Owner/Service Technician at S & J Small Engines
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I have a mod 7350 lawn boy mower I just can't start. Usual

Customer Question

I have a mod 7350 lawn boy mower I just can't start. Usual checks fresh fuel, spark and a new plug. I have used this mower twice this year. when it would start I would have to push the primer bulb on handle after it started to run to keep it running. I have removed the carb and thoroughly cleaned in side and all components. Float will float in a bowl of fresh gas.I cleaned with carb cleaner and compressed air. I have managed to get it to run by injecting some fuel into the cylinder and pulling to start it will fire and run briefly but it will not pull gas into the cylinder. Fuel tank has been flushed and primer ball and line blown out with air.
Submitted: 2 years ago.
Category: Small Engine
Expert:  Briggs-Fan replied 2 years ago.

Hi my name is ***** ***** welcome to just answer. Is this the type carburetor your lawnboy has ? , if so this will tell you exactly where the Jets are at . Also has the carbon ever been cleaned out and pushed into the muffler ?

Expert:  Briggs-Fan replied 2 years ago.

This is one way to do it ?

Expert:  Briggs-Fan replied 2 years ago.

The carbon can build up blocking the exhaust ports

Customer: replied 2 years ago.
I did the exhaust ports in Mar or Apr this year and they were fairly clean. In your reply you asked if this the type carb I have? I'm guessing you must have pictured a carb I cannot get it to download so I can't answer your question. What I can't get is the gas tank is half full and I have disassembled the carb four times ,cleaning, checking the float level, making sure all tubes ports and passages are very clean. I flushed the tank and blew out the gas line with air. But as far as I can tell the engine does not get any fuel through the carb. If I squirt some fuel into the cylinder and pull the start rope it will start and run a few seconds. I know I said a lot of this the first time but I just want to be sure I've told you all I have tried , very frustrating I don't have this kind of problems and I ju
st can't get to this one
Expert:  Briggs-Fan replied 2 years ago.
Copy the link and paste it in your Web browser , it shows the ports, jets etc on the lawnboy carburetor
Customer: replied 2 years ago.
The link you sent me is how to clean the exhaust ports ... Nothing about carburator at all.
Expert:  Briggs-Fan replied 2 years ago.
Sorry that was the link
Customer: replied 2 years ago.
John that carb pictured is somewhat like mine but way more complicated. mine is so simple I can't believe I havent uncovered a problem. At this point I guess I need you to make an educated guess on a problem I can address in hopes of solving the problem . I don't feel that whatever the problem is, is a major issue. This mower has started and run twice this season and didn't give me any trouble starting. I use fresh gasoline and Stilh two cycle oil. I use fuel stabilizer and the oil has stabilizer in it as well. I use the same gas for weed eaters,blowers,chain saws and tillers. I don't have fuel problems????
Expert:  Briggs-Fan replied 2 years ago.
Ok , I will opt out and see if another expert can help you because it sounds like a fuel delivery problem, if it will run with gas to the cylinder but run off the carb then it's not getting fuel as it should . Try cracking the gas cap , if the gas cap isn't breathing as it should then it can vapor l9ck the engine , if it runs good with the cap off you know it's a bad gas cap
Expert:  JohnF2015 replied 2 years ago.
Hi, I am thrilled that you have chosen just answer today. How can I be of assistance to you?
Expert:  JohnF2015 replied 2 years ago.
In looking at your problem. What happens if you spray carburetor cleaner into the throat of the carburetor instead of into the cylinder by way of the spark plug?
Expert:  JohnF2015 replied 2 years ago.
Hi, my name is ***** ***** I will be picking up on your question to assist you.
It sounds as if you have tried cleaning the carburetor in order to solve your problem. I think that you may have a reed plate cracked or broken but I need you to do a couple of other things first.
When you spray carburetor cleaner into the spark plug hole the engine will start, Does it continue to run any length of time? Have you checked the top and bottom crankshaft seals to see if either one of them may be leaking, this would cause the engine to not suck or pull fuel from the carburetor.
Customer: replied 2 years ago.
Hi john, sorry for the delay getting back to you, sometimes life has a way of geting in the way of getting anything of substance done. I have been able to see the reed valves and from first glance they are ok. I have not sprayed carb cleaner into the throat to get it to run,but that sounds like something I will try.As to crankshaft seals I don't know if I could determine if they are leaking. I have disassembled the carb four times to clean and check assembly. I use carb cleaner and compressed air to clean. The carb is about the most simple in construction. The maddning thing about this is how well this engine ran the the last time I used it. I use this mower for small trimming jobs and a small plot of grass. Old yes abused no.
Expert:  JohnF2015 replied 2 years ago.

At this point I don't believe that you have a carburetor problem, after all it is a very simple design and if you have had it apart four times there shouldn't be anything left in it. I would look at crankshaft seals and reed plates at this point. It is sometimes hard to tell if the seals are bad unless they have actually come out of the block, I would look for any leaks around the seals. The reed plate sometimes get wear on it and won't close properly, it could be cracked causing you to not maintain a crankcase seal if or when this happens you will normally get fuel spray back out of the throat of the carburetor and most of the time it is bad enough that it will constantly soak your air filter.