Stumped on Stihl BR450 Blower Stopping

[Mike W]

I have a BR450 that I purchased new in 2018, which has performed flawlessly until recently. I am a homeowner who uses it once a week during the summer months, after mowing, and multiple times during the Fall leaf season. I do not believe it is "worn out", like piston rings, crankcase seal, etc. I've always ran 93 octane gas, mixed at 32:1, with the recommended amount of Sea Foam in the mix to keep it clean. I've kept a clean air filter in it. The issue is that, from cold, it will crank up and run as normal, but after 5-10 minutes of wide open throttle blowing, it will quit running. I checked the screen in the muffler, and it is clean. I replaced the fuel filter and gas tank vent. I replaced the coil and the spark plug. None of these things helped. I've removed the plug during these events, and it's dry. My gut feeling is that it's the carburetor, for whatever reason not keeping fuel in the "bowl". I replaced the carburetor, and it ran as normal for a couple of weekend uses. Thinking the problem is solved, but no, the next use it died again after probably 10 minutes. When it does this, it might re-crank once or twice, but will not throttle up wide open, and eventually it won't crank at all. Fuel can be moved using the priming bulb as normal. There is no debris blocking air flow and nothing obstructing the cooling fins on the cylinder, so I don't think it is an overheating issue. The fuel line itself is about the only thing I haven't replaced, but it is supple and looks ok. Any advice is appreciated.

 

[SE#1]

Have you tried using non ethanol gas? You're describing a fuel delivery issue. Possibly, the fuel you are buying is clogging the fuel system.

There is a small screen in the carb that will gum up very fast When using ethanol. Especially, if the gas has been sitting. Are you using can fuel already treated?

Tell us more specifics: what type of gas? What type of oil? How old is gas?

I'd replace the fuel in your gas can first. Clean carb. Then replace fuel in gas can as well as blower.

If your not getting fuel to the plug and have replaced filter and carb, the screen may be clogged or a passage inside the carb. Even on a new carb, a small amount of goo from ethanol can stop the flow. Id also pressure test the fuel lines to ensure they are not the cause.

Hope these ideas help sir

 

[foresterntree]

I’d also be checking the fuel lines. Does this have a primer bulb, too? If so, check to make sure those lines are good as well. Impulse line issues? It seems like your problem is occurring after the blower really warms up, so perhaps the impulse is loosening after it gets hot?

 

[Mike W]

There is a convenience store near my subdivision that has Citgo gas, which is what I've used for over 20 years. I will go to a Shell station and get some fresh and report back.

 

[SE#1]

I would drain tank and clean carb first.

Use non-ethanol fuel in mix.

Get rid of old fuel in can first Boss.

Remember to check fuel lines, impulse line, intake boot, and primer for leaks. (If it has primer bulb)

 

[hacskaroly]

There is a convenience store near my subdivision that has Citgo gas, which is what I've used for over 20 years. I will go to a Shell station and get some fresh and report back.

I would recommend getting a quart of premixed fuel, run that and see if there is any difference, if so, then yes, the fuel you use will matter, if no then there is another issue with the blower. I mix my own gas during the heavy use season and for those tools going on the shelf, I will drain the fuel I mixed and run some of this through and let it sit the winter (or until next time I use it).

 

[lehman live edge slab]

I would drain tank and clean carb first.

Use non-ethanol fuel in mix.

Get rid of old fuel in can first Boss.

Remember to check fuel lines, impulse line, intake boot, and primer for leaks. (If it has primer bulb)

Ethanol won’t hurt the br450 it’s designed for 89 octane and up to 10% ethanol. Long as it’s fresh gas and gets used fast enough won’t really make much difference. My 026 from 1991 has had hundreds of gallons of 87 10% from before knowing better and it’s still run just fine 34 years later. 2 carb kits and fuel lines with a half dozen filters it’s whole life.

 

[lehman live edge slab]

There is a convenience store near my subdivision that has Citgo gas, which is what I've used for over 20 years. I will go to a Shell station and get some fresh and report back.

I’d put a fuel line in it since you’ve already done the filter and tank vent. Also rebuild or have carb rebuilt with new primer bulb sometimes those will get a hairline crack and the carb won’t be able to draw gas because it’s pulling air the primer. Im sure the gas you’ve been running all along is fine unless it got water in it which will cause what you’re seeing happen also. Dump your gas into a couple clear jugs and look for water after it sits. Could be running up till it fills line with water and quits, if this is the case they make a water separation funnel you can dump it through and still use the gas after that if you want to.

 

[EFSM]

Make sure the fuel line isn’t pinched. There are channels on the fan housing for them to fit into, and they can get out of place and get pinched between the shroud or air filter base and the fan housing.

 

[Mike W]

Sorry for the lapse in replying. I went to the Shell station and mixed a gallon of 93 octane. Their gas is up to 10% ethanol like Citgo, so I'm not expecting it to make much difference. Not really sure where there is pure gasoline in my town of 60k. Saturday, I took the blower completely apart again, intending to replace the fuel line, and discovered that I must have overtightened the carb, and the intake flange (which holds the carb bolts) was cracked. So I have one of those on order. I verified that the port into the crankcase, that provides "pumping power" to fill the carb bowl, is clear of any obstruction. And the port goes through the intake flange, which was also clear, although it must be replaced. The blower did run for a few uses after putting on the new carb, but it is a cheap knockoff carb, so I also ordered a rebuild kit, mainly for the thin sheet that has the diaphragm, and the one on the other side of the carb that has the little flap that closes/opens when the piston goes in and out of the crankcase. The float needle in both carbs is clean, the problem almost has to be those flexible parts. My working theory is that the original flexible parts wore out, and the second set was cheap, so I'll see what the results of the ones in the rebuild kit are, in the original carb. I will also replace the main fuel line.

 

[hacskaroly]

Not really sure where there is pure gasoline in my town of 60k.

The premixed can fuel you can get at tractor supply, Home Depot, Lowes...etc, True Fuel, Power Care, Harvest King....even Stihl and Husqvarna fuels (and for the $$$ on those) you are going to get fuel that is non ethanol and filtered. All premixed and ready to go.

 

[legdelimber]

https://www.pure-gas.org
If you're interested in chasing down some ethanol free fuel.
Don't know if anyone has mentioned the pure gas site. Maybe there's a reasonably close listing?
I do recommend calling ahead to verify the store actually has it, before making a trip though. The info appears to be user submitted and can be out of date sometimes.