Poulan Predator 35cc Model P3516PR fuel lines question

[rwh963]

Yes, CHOKE. With the choke closed, intake vacuum caused by the piston going up is presented to the engine end of the carb, pulls the fuel chamber diaphragm down and opens the inlet valve. It's this suction that pulls fuel up the fuel line and into the carb, through the fuel pump and through the inlet valve to the fuel chamber. Does the same thing as the primer, just takes longer to fill the carb, especially if the saw has a long fuel line. At cranking speed the output of the fuel pump is insignificant, it's all about the choke.

That’s interesting. I grabbed a nice snowblower from the owner as I was at my town dump. He said he had teouble starting it. Investigating at home, I had a hard time too. Turns out the primer line was rotted gone. Jury rigged a new line, fired up in two recoil pulls.

 

[Old2stroke]

That’s interesting. I grabbed a nice snowblower from the owner as I was at my town dump. He said he had teouble starting it. Investigating at home, I had a hard time too. Turns out the primer line was rotted gone. Jury rigged a new line, fired up in two recoil pulls.

Yeah, on those 4-stroke engines with a float bowl type of carb there is usually no choke and the primer is essential to get them going, the primer pump just drives a pulse of air into the float bowl causing the fuel level to rise a bit and flood some fuel into the engine. A true primer, not like the "primers" on chainsaws that are really purge pumps.