I choose saws old enough not to have a primer bulb. I like more metal and fewer dorky plastic gimmicks. I have had more problems with these than they fix.
Please explain primer bulb function
- Thread starter preventec47
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I choose saws old enough not to have a primer bulb. I like more metal and fewer dorky plastic gimmicks. I have had more problems with these than they fix.
My son showd me a trick...turn the weedeater or chainsaw upside down to make sure fuel goes to the primer bulb if it pumps nothing but air. Sometimes helps prime the primer bulb...stupid thing.
medalist
ArboristSite Operative
Well, if we are referring to the bulbs found on 2 stroke power equipment it also helps the recoil last longer. Prior to the " primer bulbs" being fitted the integrity of the fuel pump side of carb was depended on to maintain siphon.
Typically it would take a few attempts to rebuild the siphon factor. Primer bulbs helped remove these "attempts"...Echo PB210e blowers actually had a check valve in the fuel line to help out prior to primer bulbs (circa 1984 or so).
Typically it would take a few attempts to rebuild the siphon factor. Primer bulbs helped remove these "attempts"...Echo PB210e blowers actually had a check valve in the fuel line to help out prior to primer bulbs (circa 1984 or so).
If all is functioning properly, I guess that's true.
What has not been mentioned is that with many newer saws they run very lean. This raises the cylinder temperature and the heat can literally boil the mix in the carburetor. The primer bulb will supply fresh cooled mix to the carburetor and make starting easier.
The primer bulb reduces the number of pulls needed to start the engine when cold. That's about it. Then when they break down with a small crack, the saw won't even run and many times has to be taken back to the dealer for an expensive repair. 'Nuff said.
I work on my own chainsaws and have learned from experience how primers bulb 2 cycle equipment operates with and without primer bulbs.
I've noticed on chainsaws, usually Craftsman or Poulans if stored for few days, weeks or months with a dry carb they will usually start easier if they have a primer bulb. If I pull a non-primers bulb 2 cycle engine a few times in cold weather when coming out of cold storage and with a dry carb I just grab my mixed gas primer squirt bottle and prime into the carb throat or into the muffler so as to get a primed start.
I also keep spare primer bulbs ready and I do not fully press/collapse them when priming in cold weather so as to reduce the chance of causing a plastic bulb cold weather failure.
I've noticed on chainsaws, usually Craftsman or Poulans if stored for few days, weeks or months with a dry carb they will usually start easier if they have a primer bulb. If I pull a non-primers bulb 2 cycle engine a few times in cold weather when coming out of cold storage and with a dry carb I just grab my mixed gas primer squirt bottle and prime into the carb throat or into the muffler so as to get a primed start.
I also keep spare primer bulbs ready and I do not fully press/collapse them when priming in cold weather so as to reduce the chance of causing a plastic bulb cold weather failure.
thenne1713
ArboristSite Guru
It is a fact that as fuel line ages, it often STIFFENS to the point where it will NOT fall to the low point in the tank; as it ages further, it will reach a point where it CRACKS and sucks air.
If this happens, it’s because you have a leak in your fuel system. Either lines or carb and the vacuum you are creating with the bulb is drawing air rather than fuel. Turning it upside down allows gravity to take effect and thus you can draw fuel. It’s a sign to dig into the fuel system and fix the problem
Put some pressure into your fuel line and spray them and carb with soapy water and you’ll likely find it. If you don’t, remove the metering leaver and then replace the gasket, diaphragm and cover and repeat
i will be working with my primer bulb. on my SRM 266T trimmer. cracked! bit spider webbed, despite being stored inside. still functions, but my finger also gets primed! lol
I suppose it depends a little on which saw you run, but fuel line and purge bulbs are generally cheap and usually easy to replace. I run an ethanol mix because that’s what’s available in the gas here. Therefore, I expect to replace primer, fuel lines and diaphragm. But it’s so cheap and easy that fresh lines and primer are a small price to pay for reliability. Typically the fuel in take line with the filter that sits in the fuel hardens first. When it does replace everything.
Lots of the replacement tygon fuel lines and primer bulbs are the China made stuff and we pay full price thinking it's the good stuff. China can really make the poorly made stuff look like the real thing now days.
I've seen old USA made primer bulbs last for ever until the ethanol came alone, but the china stuff don't last very long.
I've seen old USA made primer bulbs last for ever until the ethanol came alone, but the china stuff don't last very long.
thenne1713
ArboristSite Guru
Have also had some filter/weights just fall off fuel line inside tank, so line sticking up in air inside tank. NEEDS Investigating, when not working right; don't IGNORE symptoms, LOLIf this happens, it’s because you have a leak in your fuel system. Either lines or carb and the vacuum you are creating with the bulb is drawing air rather than fuel. Turning it upside down allows gravity to take effect and thus you can draw fuel. It’s a sign to dig into the fuel system and fix the problem
Put some pressure into your fuel line and spray them and carb with soapy water and you’ll likely find it. If you don’t, remove the metering leaver and then replace the gasket, diaphragm and cover and repeat
Organoleptic
New Member
I have a Gardenline (ALDI) 41cc chainsaw, not used for a couple of years. The purge button does not seem to be moving fuel, just air, and ON RELEASE makes a whistling noise that seems to come from the front (saw blade end) of the engine. I have checked the filter which looks OK and tried without the filter to be sure. Does this make sense? I can't see clearly how to open the main casing to get inside even!
You can find lots of you tube info about how primer bulbs work and their function and how to test them.
Organoleptic
New Member
T
Thanks. I couldn't even dee how to get it open so took it to a local repairer who replaced the fuel pipes and spark plug
