Engine "F" engine compression and bad running issue

[Hemidude]

Hello everyone,
What is acceptable compression range for the "F" engine?
Also, after my mower has sat for a month or so, the only I can keep it running is by putting my finger in the carb opening and almost completely blocking the airway, for several minutes, until the engine builds some heat. It starts with 1 or 2 pulls and once it stays running, it's performance is rather weak....
I have taken the carb off and disassembled several times to clean it and it looks fine. I tried different float adjustments and no help.
Could the carb be warped? Since it is plastic, maybe it is shot??
Any help would be appreciated...
THX...AL

 

[mechanic mark]

https://lookup3.toro.com/ttcGateway/acrobat/manuals/lball.html

 

[beg]

had an f that ran bad Everything looked okay but it was the needle and seat

 

[bt3]

F engines can be finickey.

Mine has caused me a great deal of frustration at times, but it's a love affair so I don't mind. And it's made me a fairly decent Lawnboy mechanic in the process.

Have you checked your Reed Valves? If these are failing, it can cause you some issues. I replaced mine this year and also replaced my piston rings. I had low compression and just killed two birds with one stone. Low compression is a problem and the symptoms can be similar to what you have described. Hopefully, it's just a carb adjustment.

Keep us posted please.

 

[Hemidude]

THANKS GUYS!!! I am going to check the compression and then pull the carb again. The service manual will be a great help... If I decide to rebuild the short block, are the parts available??

 

[d_sharier]

F Series:

80 psi and under is considered low (Cold)
100-115 is considered normal (Cold)
90-105 is considered normal (Hot)

 

[Phototone]

F Series:

80 psi and under is considered low (Cold)
100-115 is considered normal (Cold)
90-105 is considered normal (Hot)

They will run reasonably well with somewhat lower compression readings, "IF" everything else, including crankshaft seals are tip top.

 

[d_sharier]

They will run reasonably well with somewhat lower compression readings, "IF" everything else, including crankshaft seals are tip top.

You are correct is stating that. My post is just a copy and paste of the information provided in the Lawn-Boy service manual. The OP asked a question and there were several responses that did not give a direct answer. So I figured if the information provided by Lawn-Boy would be a good place to start.