saw starting basics

[roundhead]

I have run into a few saws over the years that I could just never get to start. I had a 395xp that I finally gave up on. right now I have a Husqvarna 365 and a makita 510 (like brand new) that I cannot get to start. so what is the easiest procedure you follow?
1) check for spark? yes good spark
2) check fuel? new fuel but will not fire
3) add small amount of fuel to carb? no pop
4) add small amount of fuel to cylinder? no pop
5) obvious air leak? compression? do I need to take it a part and do vacuum/pressure test? check seals?
just wanted to know your procedure before I replace the carb
thanks

 

[buzz sawyer]

I pull the plug and check for spark and compression first. If I see no problem there, I put a shot of fuel in the cylinder. If it pops, I go to the fuel system - lines, filter, carb. Most of the time it's either bad fuel line or crap in the carb. If it doesn't pop, I'll try a different plug. If it still doesn't pop, I'll scratch my head for a while and try again.

 

[Mustang71]

I had a bad gas cap/tank vent do the same. I only figured it out when I had the cap off and tank empty and put some gas in the cylinder and it suddenly popped. I poked a hole in the cap and it ran fine. So I got a new cap.

 

[Tin-knocker]

I was taught to start with the easiest/simplest things first and go from there gradually getting to the more complicated/difficult repairs. You only need a fuel air mixture, compression and correctly timed spark to run an engine. Missing one of those and your engine won't run. Now you could have all of those and a running engine that runs terrible but then you just need to fine tune it. I learned how to work on engines through dirtbikes so for me it was: is the gas on? Is the air filter clogged? Is there spark? Etc. just keep moving down that troubleshooting ladder. Eventually you will find something. Most repair manuals have a troubleshooting guide that usually states a good procedure to follow.

 

[Tin-knocker]

Something similar to this. This would be for a car but you get the idea.

 

[dougand3]

From OP list in post 1...next, I'd try a simple compression test - hold handle and let go of saw - does it drop lub........lub.........lub.........lub (good) or lub..lub..lub..lub (bad). Can use a GOOD compression tester. A $15 HF one may show 1/2 the true compression.
Next, pull muffler and visually inspect P, R and intake wall.
Ball park timing check - pull recoil and set P at TDC - trailing magnet should be near 2nd coil fin

 

[ericm979]

When you start a cold saw use full choke for three pulls then turn it off (to half choke/fast idle if your saw has that). Even if it doesn't pop. It's less likely to flood the saw than waiting for it to pop before turning the choke off. If it doesn't start after a bunch of pulls it's probably flooded. Try starting with the throttle wide open. If that doesn't start it, it will help clear the gas out of the bottom end.

If your saw is stock and not malfunctioning, and you've messed with the carb adjustment, try turning the adjustment back to the stock starting point as listed in the manual. Some people can get the carb adjustments way out in left field. Starting over can be a good idea.