Got A Saw That Won't Prime with Bulb, And You've Tried Everything... Try PB Blaster

Birdyman88

Well-Known Member
I have a 193T that, like other people, gave me fits when it was new. The main problem was with the idle, and stalling with throttle. I wrote in another post about how a timing advance and muffler mod saved that saw. However, I had a problem since day 1 that has persisted and never been solved, and that is that the primer bulb will not purge the system very well and the bulb does not want to fill completely. I tried everything, literally everything including checking every little hose and part for leaks. Dealer has looked at it once, changed the bulb, and said nothing was really wrong. I finally said forget it, because the saw starts just fine without it. However, if you're really observant, you'll notice that the saw stutters slightly when you bury the trigger, but then catches up and revs just fine up to max rpm. That and the long history of idle issues. As of late, the primer draws no gas at all.

So, I got to looking at it again. One thing I noticed is that when you press bulb and release it, you hear a gurgling/sucking sound coming from somewhere down inside the carb that has been there since the beginning. I could not pinpoint the location, though I did guess that it sounded like it was coming from the venturi. I called the carb manufacturer, and after a long chat with a very helpful tech, we thought that it may be a stuck idle air check valve. This would allow air to pass from the venturi back into the metering area if vacuum was applied to metering area. It might also affect the running of the saw at idle if the check valve was not able to move freely.

So, I soaked the carb in gas for an hour, then reassembled and tested. Nope, no go. Then I disassembled the metering diaphragm and tried to cycle the idle air check valve with my mouth and a hose then tried it again. Nope, no go, except for a nasty 50:1 flavor in my mouth. Next, I disassembled again and popped the idle air jet with some short high pressure air bursts and tried it again. Nope, no go. Then I disassembled one last time, but this time I sprayed the whole carb with PB Blaster and let it sit. Then, I hit the idle air check valve with air bursts again and reassembled. Guess what? It worked! The primer bulb now works, that sucking noise from the venturi is gone when priming, and the stutter when I bury the throttle has disappeared. According to the technician, these things just happen sometimes, and can be exacerbated by ethanol. This saw did have ethanol fuel run through it for about a year, though it has been doing it since I first bought it. Anyway, PB Blaster saves the day again.
 
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Birdyman88

Well-Known Member
PB Blaster does a good job of breaking things free. Example is I've used PB Blaster on O2 sensors with 200,000 miles that wouldn't budge. A shot of PB Balster and 30 minute wait and they broke free with little effort. I can't remember if WD40 had the same type of breaking action or not.
 

39Buick

Well-Known Member
WD40 is nothing like it used to be! And there is no comparison to PB Blaster. Anytime I ever have issues with any carb I use the old reliable Berryman Chem Dip! Take it apart and drop the pieces into the basket and drop it in the can and seal it up! Hour or two later hit all the parts with compressed air and your ready to go! Will have to try PB Blaster on the next one!
 

Birdyman88

Well-Known Member
Well, cured another carb with PB Blaster yesterday. I have pressure washer with Honda engine that gets used about once a year. I had to clean the jets a fews years back due to ethanol damage. Been running non-E since.
Was washing my rental the other day and the machine would die after 5-10 minutes of running. All the standard checks were fine, including fuel tank vent. This went on all day until it finally just quit completely. Got it home, laid it on its side and shot it full of PBB and let it sit overnight. Next day, cranked it up, it blew smoke everywhere, and it ran perfect for 8 hours straight.
 
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