Stihl 051 dies/hard to start when hot

[comoxmcgyver]

Ok, now that I've adjusted the carb..... the saw dies when hot and I can't get it to start. If I choke it I can get it to turn over but immediately dies as if it is starved for fuel. where to start..I really don't want to put much $$ in to this old saw. Just spent $50 to change the oiler pump. Thanks

 

[klickitatsacket]

it kind of sounds like you might have a vacuum leak associated with heat. When the saw heats up it opens up a hole. make sure the bolts holding the intake and carb are tight after it is warmed up. (do not over tighten) Also check the jug bolts. After this I would go to the seals.

 

[Pacific]

Thats just like my old mans 051 i traced it down to a fuel tank thats not venting properly I crack the cap then the saw starts fine. I tried cleaning the tank vent I dunno it really didn't work that well. It was like the gas was boiling from the heat when ever I took the cap off the fuel was bubbling.


I try to leave the cap a little loose but that always doesn't work because the viberation usually rattles the cap all the way off and you end up with gas all over your leg.

The other thing to remember is use the decomp valve or your fingers will be hurting when the saw kicks and pulls the cord out of your hand
When the saw sat for 2 weeks or more she was a sucker to get started I usually had to pull the filter off and pour some saw gas down the carb.

I retired the old saw and gave it back to the old man after I used it for quite a few years bucking firewood. I replaced it with a 046 Mag with a 28 it doesn't have the the torque of the 51 but its nice to have a lighter saw.

 

[canguy21]

Check the intake gaskets, use new if possible and check the insulator block for cracks. Also make sure the gaskets are installed correctly so the impulse passage is not blocked. Those old battleships were well known for air leaks.
I started in a Stihl shop in the mid seventies and saw a lot of those with 29 inch bars. They were nasty when that little bitty oil pump o-ring failed and flooded the crankcase. My fingers go numb thinking about it.