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murph64
04-28-2009, 06:06 AM
Dumb question...But would a cracked primer bulb cause it not to start? It's a Stihl BG55 leaf blower, and it worked fine last weekend.


Andy

Doc Nickel
04-28-2009, 06:21 AM
It shouldn't. But that assumes the crack is letting in neither additional air nor gas, either of which will obviously throw off the mixture.

You might switch the ignition off, pull the plug and give the starter a few hefty yanks in case it flooded. Scuff the plug electrode with a bit of emory paper before you put it back in, and give 'er another try.

Doc.

Ian B
04-28-2009, 07:03 AM
Murph,

Do you have a spark? Unscrew the plug, put it back in the plug cap & earth the plug body. Spin the engine, check for a spark.

If there's a spark, will the engine fire up on easystart? Spray some into the air intake, see if it tries to fire, then dies. If it does, then go through the fuel system; maybe start by replacing any old fuel with new.

Ian

Circlip
04-28-2009, 07:18 AM
Muck in the Cuberootcrater jet?

Regards Ian.

Norman Atkinson
04-28-2009, 07:36 AM
err, Mister????? Primer bulbs on Stihls do not CRACK-- unless they are a million years old. They may split with ageing( I know the feeling)

Still waters run deep-----Ho, Ho.

N

murph64
04-28-2009, 07:43 AM
I didn't have the chance yesterday to pull the plug, but the air filter looks OK. And it worked fine last weekend, that's what has me scratching my head. When the kiddie takes a nap later I will get the round tuit out of the secret drawer and check it out a bit more.



err, Mister????? Primer bulbs on Stihls do not CRACK-- unless they are a million years old. They may split with ageing( I know the feeling)

Split, then...That's the term...Especially if some unnamed dummass left it outside all winter.



Still waters run deep-----Ho, Ho.

N

Boooooooo....<looks around for an e-tomato to throw> :D

Norman Atkinson
04-28-2009, 07:54 AM
On bonus or onus?

We are all in need of a laugh. First the economic situation and then the in- flue- enzer and now the Still waters of Mohican Lake.
I put it to be red- last.

Oh, never mind

Norm

Ron of Va
04-28-2009, 10:52 AM
Even with a split primer bulb, the engine should fire.

I suspect a fouled sparkplug.

Out of gas, or clogged fuel line, bad on/off switch are other possible suspects.

Clogged air filter will usually give you some warning, such as surging, failure to reach proper RPM, etc.

Clogged carburetor jets will usually give some warning too (but not always).

radkins
04-28-2009, 11:04 AM
Murph,will the engine fire up on easystart? Spray some into the air intake, see if it tries to fire,Ian



Spraying Ether (Easy start, starting fluid, etc,) in a two stroke engine is a really bad idea in spite of what the label instructions might say. Look at how a two stroke is lubed and it easy to see that if it starts and runs, even for a few seconds, it is not only running without lubrication but even the mist from that stuff will destroy what remaining oil that may be left on the engine internals, what precious little is in a two stoke anyway. I have seen several chain saw engines ruined this way and it seems the piston/cylinder is more likely to gall than bearing failure but I have seen both and either is a disaster!

lakeside53
04-28-2009, 11:04 AM
A BG85 with a split primer blub will not be able to pump gas - it will let air into the metering chamber. More than that, if it is split it's a sign of old gas (like storing it with gas for a year..) and you likely have varnish in the carb.

Take the carb part, clean it out with CRC Brake Clean (not carb cleaner - affects the internal valves), and do NOT blow though the holes with compressed air -you will ruin the outlet valve and internal check valves, the internal are not replaceable. Re-kit it and adjust the metering lever to level with the top of the carb body. Zama kits are about $7.50-$10 and the primer bulb about $4.


If it is flooded, take the plug out, ignition off, turn the machine upside down - pull away until it stops spitting gas out of the plug hole. Clean the plug with carb or brake clean.


Oh.. I see this stuff often - I'm a Stihl tech..

Mike Burdick
04-28-2009, 11:33 AM
If none of the above suggestions solve the problem then you might purchase a gasket/diaphragm kit for the carburetor - the kit usually cost under $10.00. The diaphragms develop small pinholes that prevent the engine from running.

When installing the kit make sure the diaphragms are installed in the correct direction! A few digital photos of how the old ones were placed is a great help!

Tinkerer
04-28-2009, 01:30 PM
Also go over it and tighten all bolts the damn things vibrate as bad as a HD. I had to do this to mine last year when it would not start. The end closure that completes the case was loose... found that after pulling the breather box off. The bolts worked loose and after a good go thru it's back in running order. My did just as your ran the week before then yank... yank... yank... *&#@ :mad:.


:D

Jim Caudill
04-28-2009, 11:00 PM
You may have a bad ignition module. I have a Stihl "string trimmer" and I was using the thing just fine til I ran out of gas. Refilled the tank and never could start it again. After not having it run for 2 years, I finally got after it and discovered "no spark". $30.41 plus tax and it fired up on the second pull. I believe your blower uses the same ignition module. Some of the ones from around 5 years ago were subject to static discharge failures. Very common out west where the air is dry. The module was redesigned based on the issue.

Check for spark before messing with the carb.

radkins
04-28-2009, 11:39 PM
Check for spark before messing with the carb.


Exactly!

ALWAYS be sure you have identified the problem before "fixing" anything! :)

jnissen
04-29-2009, 02:00 AM
I deal with two strokes all the time. Manulally choke it. Put your finger over the carb opening while pulling it through.. do you get a wet finger with fuel/oil on it? If yes then your at least getting fuel up to the carb and it may just be the diaphragm and cracked primer.

It should pop to life if you managed to wet your finger by manually choking it this way. If no fuel then your fuel lines, tank pick up and possibly the carb inlet screen can be plugged. Don't forget to replace the fuel in the tank. If the thing really was out doors for a while you can pick up water in the fuel (condensation and or actual contamination with rain, etc...) When in doubt use clean and new fuel. If the primer is cracked the fuel lines are almost certainly toast. Yellow tygon lines should be used and replace all of them.

Of course verify the spark if your not getting any life out of it. Spark plugs to go bad and should be replaced periodically! I prefer NGK plugs but then again the two cycles I deal with are race motors that see close to 18,000 RPM.

http://www.cc-racingengines.com/index.php?option=com_oscommerce&osMod=product_info&Itemid=32&cPath=1&products_id=79&osCsid=8a286b331e9eec0a3d58aa7a9c9fd01

Peter S
04-30-2009, 05:02 AM
I fixed my brothers Echo line trimmer recently, the same problem - split bulb, no go. I think it had got dust into the carb through the damaged bulb, because when I fitted the new bulb, the carb flooded and so I had to dismantle and clean the carb (needle jet in particular). Then it went well. I was surprised to see that pumping the bulb actually pressurises the fuel tank, thus sending fuel up to the carb, thats how it seemed to work anyway, I could be mistaken.

BTW, when my brother bought this a few years back from a Stihl/Echo dealer, they recommended the Echo as a better line trimmer....?

Norman Atkinson
04-30-2009, 05:19 AM
Frankly, who cares about Echo, Stihl, Pioneer or whatever?
The point is that if whatever it is, will not go it is either mended or dumped.
Replacing worn out items is what HSM is all about.
One thing is certain, the fairies at the bottom of the garden are a lazy lot and the chances that somebody on HSM who will actually mend it, is in the Rocking Horse manure category.

Grumpy? Merely realistic!

Next?

Norm

murph64
04-30-2009, 08:43 AM
Then it went well. I was surprised to see that pumping the bulb actually pressurises the fuel tank, thus sending fuel up to the carb, thats how it seemed to work anyway, I could be mistaken.


That would explain why when I almost overfill the tank, it comes spitting out the vent when I hit the primer bulb....Interesting

The round tuit is still in the drawer, so the machine remains not touched :(


Andy

airsmith282
04-30-2009, 10:26 AM
yes a buggered primer bulb can prevent the engine from starting,,you can run a by pass and go without but harder to start then , check for sprark replace the bulb if it stilldont run rebuild the carb and go back to step one and try to start it agian,, if it still has issuse turnt he adjuster screws in if you have 2 of them turn until the stop on there own back off hte L 1/5 turns and the h to 1 turn to 1 1/4 turn then try starting it again,,

lakeside53
04-30-2009, 11:52 AM
I fixed my brothers Echo line trimmer recently, the same problem - split bulb, no go. I think it had got dust into the carb through the damaged bulb, because when I fitted the new bulb, the carb flooded and so I had to dismantle and clean the carb (needle jet in particular). Then it went well. I was surprised to see that pumping the bulb actually pressurises the fuel tank, thus sending fuel up to the carb, thats how it seemed to work anyway, I could be mistaken.




On the small stihl's - it doesn't work that way (I don't believe the Echo's do either) - take the fuel cap off - it will still pump gas to the metering chamber. The carb fuel pump side of the carb is not supplied with gas when hand priming, and the engine is not primed - just the metering chamber preloaded waiting for the engine to turn over and create a negative pressure in the venturi.

pcarpenter
04-30-2009, 01:27 PM
If the primer bulb is split, likely the carb is in need of other work (due to age). The bulbs get embrittled when pretty old.

Here, however, is something I posted in a recent thread about chain saws. I cannot tell you just how universal I have found the issue with the in-tank pickup/filter to be. The stuff that plugs it is fine enough that you can't really see it. The problem only worsens with time as each tanks worth of fine particles is added to with the next tank full of gas. This is the reason that Stihl even tells you to replace the thing annually. Once you figure out how to re-thread the fuel line (buy a longer length than you need to give yourself a leader to pull) the process is not that hard.

Paul



After having problems with a nearly new string trimmer years ago, I learned something (with the help of my father) that has solved problems for me many times over.

Nearly all 2 cycle equipment has a pickup/filter element that flops around in the tank. The amount of time it takes for these to suck themselves full of microscopic stuff in your gas can vary from mere minutes to months. Put some not-so-ideal fuel in and it can be seconds before you start having problems. If you leave these items sit for a while, the stuff matted in the filter (too small to be visible) falls back out and it runs great....for a while until it becomes clogged again. The filter medium is so tiny that the stuff it takes to cause fuel starvation is too tiny to be clearly obvious.

I have had lots of 2cycle stuff that would exhibit exactly the symptom described....ran great for a while and then would be hard to (re) start and would die as soon as you hit the throttle. The aforementioned string trimmer was given to my father when I bought a Stihl trimmer. He figured out that the problem was that little pickup/filter and replaced it and it worked fine for him for a good while. I have since gone to fixing the problem at the source when it re-occurs with equipment I own and all is well. I dump the small amount of fuel in the tank and replace the element (which can take some work since you have to pull the line and element up where you can work on it and then pull it back into place. I keep some of the tiny fuel line around so I can just replace it if its easier.

My Stihl instructions (I now have a Stihl string trimmer, blower, and chain saw) all indicate that this filter is to be replaced after just a few months of use. That seems short, but I would argue that one batch of fuel with some tiny fines would plug it up in mere minutes of running. I have also found that the Stihl stuff was less prone to problems since their fuel pickups/filters are larger. More surface area seems to reduce the issue to a tolerable level.

One change that has helped a lot....I went to using Stihl's 2-cycle oil. It's a bit more expensive, but I have never had the slimy gel that would form in the bottom of the can that I got with other brands. I also switched to a galvanized can since a local repair place indicated that they found the jelly a lot in plastic cans and tanks. The hunch was that its one of the many creepy additives in gas reacting with the plastic. Either way, this clear jelly stuff is almost invisible and would clearly wreak havoc with these tiny filters.

Edit-- one other tip-- I don't leave fuel sitting in the tanks on my 2 cycle stuff...at least not at the end of the season.

Peter S
04-30-2009, 08:16 PM
On the small stihl's - it doesn't work that way (I don't believe the Echo's do either) - take the fuel cap off - it will still pump gas to the metering chamber.

lakeside,

On the Echo, pumping the bulb, then taking the fuel cap off, released pressure in the tank, that is where I got the idea from (I didn't try pumping with the fuel cap off). However, this was before I cleaned the carb. Working the primer was also making petrol overflow into the carb, this came right when I cleaned the needle valve. I am pretty sure there are three tubes from the fuel tank, one is a breather with check valve to allow pressurising.

firbikrhd1
04-30-2009, 08:22 PM
One thing I haven't seen mentioned yet (perhaps I missed it), is the possibility of an exhaust port or spark arrester screen that's clogged with carbon. Depending on how old the unit is, how much oil has been mixed with the fuel, hours, etc, carbon can build up to the point that the engine can't take in air. Pull off the muffler/clean out the exhaust port and use a propane torch to burn the carbon off the screen in the muffler, put it back together and see if it starts. It's worked for me!

lakeside53
05-01-2009, 12:58 AM
Oh yes... always check the muffler screen on those blowers. The BG series unscrews.

murph64
05-22-2009, 10:56 PM
One thing I haven't seen mentioned yet (perhaps I missed it), is the possibility of an exhaust port or spark arrester screen that's clogged with carbon.


You win the cigar...Only it was mud, not carbon, that was plugging the hole in the muffler...

And I got my riding mower running today, too...:D

Andy

Arcane
05-22-2009, 11:03 PM
Good gawd! Don't start talking about holes in mufflers and 2 strokes!

dp
05-22-2009, 11:05 PM
I had a split bubb on one of my machines and found a supplier on Ebay. A few bux and a couple days later I had a complete carb rebuild kit and a running motor again.

With the bubb cracked I had to drown the engine by pulling the air cleaner off and dumping gas down the throat. Later tried Diesel starter and that worked, too, and didn't require pulling the AC.

There's just a few itty bitty carb makers and getting parts for them turns out to be a pretty easy thing to do. I even found a carb kit for my old Mac 10 chain saw and it has one of the classic pumper carbs. Runs like a champ, now.

firbikrhd1
05-23-2009, 11:17 AM
Murph, Better make that a bubble gum cigar, I get enough smoke at work already. Glad it worked out for you!
Steve