I hate primer bulbs...

[edisto]

Almost nothing I own has them, but all my buddies that leave fuel in their box-store 2-strokes and want me to clean the carb have equipment with them.

The last one was a Ryobi pole saw with the bulb built in to the Zama carb. Once i got it back together I found that it wouldn't prime or run because the check valves were shot. I drilled out the check valve that pulls fuel through the carb and plugged it with a set screw...but only after I built a butterfly valve (out of a Canadian dime), because apparently primer bulbs are so awesome you don't need a choke any more.

It starts and runs just fine with the new choke.

Then yesterday, I finally got my FS250 (it's actually an FS120 with a 40cc FS250 P&C) running and was tearing through the brush with it...it died about 15 minutes in because the brush had torn the the primer bulb out of the housing and off the fuel lines.

Cut off the fuel outlet tube and drilled and tapped it for a screw to plug it and cut the fuel line back to the grommet and plugged it with a screw as well.

It starts just fine.

So why all the damned bulbs? Just more parts to buy? They don't help with starting enough to be worth the hassle of messing with them when they split or fail some

I know, this has been covered many times before, but I'm not really looking for answers...I just wanted to vent.

 

[Canyon Angler]

The primer bulb on my Dolmar cracked and fell apart but I just used the choke instead for three or four years.
Finally took the saw into the shop for something else and my mechanic replaced it, not that it needed it ...

 

[Big Red Oaks 4 me]

I hate primer bulbs, too. When using premix or ethanol-free fuel, they usually last a long time, though. Some people use the end of their index finger to prime, and that's hard on them. I use the wide part of my thumbprint, so not to put much "pointed" pressure on them.

 

[Wood Doctor]

A failed primer bulb can eventually lead to carb ruin. The carb cannot be fixed by replacing the bulb or even be rebuilt. The carb must then be entirely replaced. I've run into this several times.

What does a primer bulb save? One or two pulls on choke with a cold engine? That's about it.

 

[NSEric]

I like em, your saw can set for a month or 2 and still start in 2-3 pulls with them and I haven't had an issue with one breaking yet.
When or if ones breaks I'll just plug the lines with a screw.

 

[s sidewall]

Only saw I wished had a primer bulb are my Poulan 2000's. Those are a pain to prime when you run out of fuel, over a foot of fuel lines.

Steve

 

[s sidewall]

Only saw I wished had a primer bulb are my Poulan 2000's. Those are a pain to prime when you run out of fuel, over a foot of fuel lines.

Steve

 

[edisto]

A failed primer bulb can eventually lead to carb ruin. The carb cannot be fixed by replacing the bulb or even be rebuilt. The carb must then be entirely replaced. I've run into this several times.

What part of the carb fails? The Zama carb wouldn't run with the check-valve stuck open, but drilling it out and tapping it for a set screw worked.

What does a primer bulb save? One or two pulls on choke with a cold engine? That's about it.

The two that I plugged this weekend both started quite well without them. Better than my Husqva-Poulin 41 does!

 

[SEAM]

...it all depends on the primer in question. Some draw fuel through the carb, some pump fuel into the bore, and some pump fuel into the carb. A primer malfunction may cause air being drawn into the carb through the priming passage, posing a risk of running the engine too lean, and eventually might cause a seizure. This can happen with a torn bulb, for example, if the duckbill/check valve below it gets dirty. I usually plug the priming port(s) on the carb side to avoid getting any dirt inside.

 

[Old2stroke]

An easier way to plug a port is to pull the line off, push a small ball bearing up the line and then put the line back on the port. The rear wheel of a multi speed bike has lots of small bearings. I wish a couple of my big saws had primers on them, damn near ruin your arm getting fuel up to the carb if they have been sitting for a long time. I squirt some fuel into the carb intake to solve this but a primer would save taking the filter apart to get at the carb.

 

[rngrchad]

Weird. The primer bulb on my 346xp from 2007 is in great shape. Maybe this is a clue to purchase Husky primer bulbs?

I do agree, I would rather not hAve my saws equipped with them though as it’s just one more extra thing to fail in the worst possible moment but if they do it’s easy enough to replace them in the field.

 

[NSEric]

I have a 02 jred 46 aka a poulan with a primer bulb that's still fine. I don't like this saw, it wont hold a tune and the chain brake is broke but I could put gas in it, push the primer a few times then fire it up in 2 pulls and its been sitting for a year because I bought the bigger better timberpro.

 

[edisto]

I do agree, I would rather not hAve my saws equipped with them though as it’s just one more extra thing to fail in the worst possible moment but if they do it’s easy enough to replace them in the field.

You really take spare primer bulbs into the field? I modified the FS250 so that I wouldn't have to.

With the pole saw I described, it wasn't the bulb that was the issue. The primer was integral to the carb, and it was the check valves that were shot (granted, the owner had left fuel in the tank for so long the fuel lines were gone, and the filter had started to corrode). With the open check valve on the carb side, the saw would not run. I had to drill the valve out of the carb, and tap the hole for a set screw or buy a new carb.

 

[a. palmer jr.]

Lawn Boy mowers use a primer bulb instead of a choke and actually work better unless you give it too many pumps.

 

[NSEric]

Lots of older sleds have primers too, they start in 1 pull if you prime it the right amount of times.
When its warm out I push the "primer bulb" 1/2 a dozen times and don't use the choke on my Chinese saw, its stats in 2 pulls this way, with the choke on it takes 2 pulls with choke then 2 after you take the choke off. Primer bulbs on chainsaws are actually purge bulbs, they fill the carb with fresh gas out of the tank, you cant push them too many times nothing bad happens if you push it 100 times, they don't squirt gas into the cylinder like real primers on sleds and stuff. One plus other than less pulls to start a saw is if your saw has been setting for a long time you can push the primer a bunch to flush the old gas out of the carb before you try to start it, its like a quick carb cleaning, they start right up if you do this most of the time.

 

[Canyon Angler]

if your saw has been setting for a long time you can push the primer a bunch to flush the old gas out of the carb before you try to start it, its like a quick carb cleaning, they start right up if you do this most of the time.

Where does the "old gas" go if you flush it out with the primer bulb?

 

[SEAM]

...gets returned into the tank...

 

[dougand3]

An easier way to plug a port is to pull the line off, push a small ball bearing up the line and then put the line back on the port. The rear wheel of a multi speed bike has lots of small bearings. I wish a couple of my big saws had primers on them, damn near ruin your arm getting fuel up to the carb if they have been sitting for a long time. I squirt some fuel into the carb intake to solve this but a primer would save taking the filter apart to get at the carb.

And the Poulan 2000, Micro XXV genre. 14" of fuel line is a whole lotta pulls when you set saw on shelf for a month.

 

[edisto]

Lawn Boy mowers use a primer bulb instead of a choke and actually work better unless you give it too many pumps.

I have never had to replace a choke though...

 

[sunfish]

Have a few trimmers / saws with (air purge) bulbs and never a single problem. One Stihl & a couple Husqvarna.