Will not start after engine is hot

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Your carb primer bulb is probably not working right. The prime from this primer bulb acts as the choke sending xtra fuel in the carb!



primer bulb?? How does that come into play when engine is hot. 3 prime pumps at cold start and it fires right up. I have never used the primer after engine hot. Are you supposed to?
 

Mower King

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primer bulb?? How does that come into play when engine is hot. 3 prime pumps at cold start and it fires right up. I have never used the primer after engine hot. Are you supposed to?
You might have to prime it, even hot. As a engine gets wear on it, it doesn't react the same as when new....same with the carb. Try it, to find out.
Nothing fires an engine faster than fresh, raw fuel!.......well, there is a couple things but I don't print it, don't really want anyone getting hurt!
 
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Ok, so now I am straight on this is the THROTTLE. Does the throttle butterfly have anything to do with original problem. Pulling on the rope forever to get it to fire up again after dumping grass catcher. It seems to start up pretty well if you let it cool down. So maybe back to this thermostat thing? I am not seeing one around my muffler area. Here is a pic of muffler.
 

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You might have to prime it, even hot. As a engine gets wear on it, it doesn't react the same as when new....same with the carb. Try it, to find out.
Ok I will try to prime it tomorrow on a hot engine to see if it helps it start. This is a 15yr old mower by the way so it won't surprise me if the primer is malfunctioning. There again as I stated above this is why I am trying to fix it for the neighbor instead of a small engine shop at $30 an hr.
 
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Spark plug looks fine by the way, first thing i checked along with the oil level.
 
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Oh, you don't even have a choke..... that's the throttle which controls engine speed. a choke would be right behind the air filter. that metal link going into it is the governor link, and the spring that goes to the control panel on the front is the governor spring, when tension is increased on that spring, it runs faster. it may need more tension or a new spring.
A choke would be where i circled.

View attachment 53990
Ok, no choke, not sure I understand the concept of no choke system, but I got it. I sure miss the mowers I grew up with. Mounted on the handle was a throttle/choke control with a turtle and rabbit icon. Worked great until all these kill levers and such came along.
 

bertsmobile1

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Ok, so now I am straight on this is the THROTTLE. Does the throttle butterfly have anything to do with original problem. Pulling on the rope forever to get it to fire up again after dumping grass catcher. It seems to start up pretty well if you let it cool down. So maybe back to this thermostat thing? I am not seeing one around my muffler area. Here is a pic of muffler.
If there is no choke then there is no need for a thermostat to control it
You may have a worn out carb or an air leak around the carb.
 

Scrubcadet10

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Ok, no choke, not sure I understand the concept of no choke system, but I got it. I sure miss the mowers I grew up with. Mounted on the handle was a throttle/choke control with a turtle and rabbit icon. Worked great until all these kill levers and such came along.
as bert said, since you don't have a choke, you won't have the thermostat to control it.
if you don't have a choke it uses a primer bulb... usually a red rubber button you push.
 
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Understood. Thermostat is for choke system engines. I have the primer bulb system. I am going to prime it with it hot and not starting to see if that fixes anything tomorrow. If priming helps, then I will change just the primer bulb. Still a little confused about how this is causing hard to start condition on a hot engine. I thought the primers sole purpose in life is to prime a cold engine on first start and that is it. How is it affecting a hot engine? Rubber leaking maybe allowing too much air in the carb???
 
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