Can anyone help diagnose my Echo leaf blower?

[hmbemis]

Echo PB-580T about 4 years old.

Was starting/running fine one week, the next week the trouble started.

Symptoms:

• If I manage to get it running, it only runs at WOT and is slow/bogged, smokes a lot, dies immediately off WOT and won't restart
• Several times I've found the air filter soaked with fuel after sitting upright/normal
• Pulling fuel line it will sometimes flow by itself until I open fuel cap, even after sitting for days

When issue started I replaced the fuel filter, air filter, and plug w/ one of those tune up kits from Echo -- no change

I found I was getting it to run for a second on carb cleaner sprayed into spark plug hole, so I assumed it's a fuel/air issue, not spark/compression but maybe I'm wrong?

I noticed the purge bulb seemed to be sucking air, bubbles were obvious in the return line (bulb wasn't filling w/ fuel totally, and would always have air in it)

Pulled carb totally apart, cleaned everything, reassembled, same symptoms. Also blew out both fuel lines w/ carb cleaner, no blocks

Tried starting w/ fuel cap off but didn't help.

I assumed my fuel-soaking might be a carb issue... Bought $18 Chinese carb from Amazon, but still won't start -- however this purge bulb acts normally. I will also say, this time couldn't get it running w/ carb cleaner in the plug hole, and the air filter had been wet w/ fuel when I opened it, so I'm thinking it might have been badly flooded at the time by the old carb? Was also only 30F outside.

Aside from finding a local pro, what should I be checking/trying next?

 

[decableguy2000]

Check the spark arrestor screen in muffler to see if it's clogged. Pull the plug and let it sit for a while to see if you flooded it. Verify that you didn't cross the fuel and purge lines. Use caution with carb, brake cleaner, starting fluid on a 2 stroke, washes the oil off the cylinder.

 

[hmbemis]

Check the spark arrestor screen in muffler to see if it's clogged. Pull the plug and let it sit for a while to see if you flooded it. Verify that you didn't cross the fuel and purge lines. Use caution with carb, brake cleaner, starting fluid on a 2 stroke, washes the oil off the cylinder.

Should have mentioned --

Even before the plug I pulled the spark arrestor -- totally clear.

Fuel is also not an issue, it's a new can of Trufuel which I had been using in it, my chainsaw, and string trimmer w/o issue. I did dump all the fuel out and refill as well "just in case"

Fuel and purge lines are correct -- verified with diagrams, but great suggestion!

 

[Great white]

I don't have an echo, but this applies to most small yard equipment 2 strokes:

Check the spark arrestor as mentioned. Seen lots of them either carboned up or a mud wasp gets in there and plugs the screen. It happens, had to do my Stihl leaf blower this summer. Left it on the deck one night and the next day it wouldn't start. Mud wasp.....

Then, carb cleaning and a rebuild kit is the next most likely thing on these small 2 strokes. Spraying carb cleaning in it won't do the job if it's varnished up from fuel. It needs to be either dipped or spend some time in the ultrasonic. Nut, you say you've tried a new carb, so that's not a likley issue here.

There's a fairly easy rule of thumb for checking compression on these little engines: hold the pull start handle and let the until hang on the rope. If it stays where it is, compression is certainly good for starting and likely running. If the unit slowly lowers against the recoil spring, compression is gone. this is often refered to as the "drop test".

8 times out of 10, low compression on these little 2 strokes is a result of too much oil in the premix and it carbons up the piston rings, causing them to no longer seal. 2 strokes run fairly dirty by their very nature. Get even a little too oil rich on the mix and it will cause issues over time.

I've never had any luck "de-carbonizing" them without pulling the cylinder and manually cleaning them. Last one I did was a Poulan and the rings were so solidly carboned they wouldn't come out without breaking them, even after a couple rounds in the ultrasonic. You can try putting the piston at TDC and pouring something in there, but even if that works, it's a temp fix at best.

Don't pour anything in there if it passes the "drop test" though.

 

[hmbemis]

8 times out of 10, low compression on these little 2 strokes is a result of too much oil in the premix and it carbons up the piston rings, causing them to no longer seal.

Ugh, this is definitely a possible component -- prior to this season, where I've been running Trufuel, I was mixing it myself and I'm fairly sure my most recent 2 gallons was more like 15-20:1 because I think I double-mixed. I didn't think too much oil would be an issue.

I'll try the drop test, and I do have a compression tester too, I just need to dig it out.

 

[The Cobbler]

Several times I've found the air filter soaked with fuel after sitting upright/normal

with the sypmtoms mentioned, and the quoted portion above, I would be looking at the carb, needle & seat & diaphragm in particular

 

[Great white]

with the sypmtoms mentioned, and the quoted portion above, I would be looking at the carb, needle & seat & diaphragm in particular

Low compression will do that too. Still enough vacuum to pull fuel, not enough to combust it so it just sort of "blows it back and forth" in the muffler and carb. Soaks the air filter because these carbs are very short and the filter is right behind the choke plate....

 

[Great white]

Ugh, this is definitely a possible component -- prior to this season, where I've been running Trufuel, I was mixing it myself and I'm fairly sure my most recent 2 gallons was more like 15-20:1 because I think I double-mixed. I didn't think too much oil would be an issue.

I'll try the drop test, and I do have a compression tester too, I just need to dig it out.

Wow, that's really rich!

My Stihl stuff (blower, chainsaw, whacker, etc) runs 50:1

I just buy the small bottles of Stihl oil in the 6 pack and have a can dedicated to premix only. The can is sized so I just dump a bottle of oil in and then fill with fuel. Gets me a 50:1 premix and filling the gas part mixes it all well.

I have a preference for Stihl, but they command a premium at purchase and man, are parts pricey when they break.....

 

[RickyPetite]

Don't assume that the fuel is ok. Check out this video. Truefuel performed horribly.

 

[Great white]

Never heard of "TrueFuel". I can't imagine throwing something in a 2 stroke where I wasn't controlling what the ratio is. Maybe I'm just getting old and prefer the way Ive always done it.

The oil has nothing to do with the carb, it's in there because 2 strokes are essentially "dry sumps". That's why you can run a 2 stroke upside down (until the fuel pickup is uncovered).

The oil is in the fuel to lubricate the crank and piston rings, nothing else.

 

[theoldwizard1]

Start with fresh fuel, properly mixed. NO CANNED FUEL !

The tank should not hold pressure unless it was stored hot. Does it start and run OK after venting the tank ?

2 strokes are very picky about air fuel mixture. Any small air leak can cause a problem. Start by removing the outer case. First check the muffler and spark arrestor to make sure they are not clogged. Then look for areas that seem to have a lot of oil/dirt build up, especially around the carb/intake, the exhaust, the starter "cup" (where the pull start engages the crankshaft) and where the cylinder (jug) attached to the block. You need a vacuum/pressure tester to properly check these, but it is probably not worth buying one.

This video is long, but the link starts at the important part (the guy had already spent many hours fiddling with it).

.

 

[Davefr]

I have yet to read that you replaced or tested the fuel lines. Right below the grommet is a trouble spot for leakage and/or constriction.

 

[geneg]

I agree with Davefr. A pinch or hole in one of the lines can create all sorts of issues. Get new lines, a new filter, a new purge bulb & make sure they're routed properly. You switched carbs to no avail, so that isn't the issue. You have spark-- so it can run. Remove the plug. Spray a few squirts of marvel mystery oil in the hole & let it set overnight. The next day pull the cord repeatedly. Then install a new or clean plug, fresh fuel, & it should run.

 

[dvblanch]

Does the fuel tank have 3 lines? one may be a vent that runs up under some of the plastic housing & have a small check type thing in it that can stick & allow fuel tank to pressurize. Can always crack the fuel cap to release before storage

 

[Pinemarten]

It is running really rich as indicated by the "4-stroking" rough running. The soaked filter indicates overly pressurized fuel tank, or a drooling main jet. Both of these symptoms point to too much fuel being delivered.

Put the original carburetor back on it. It ran a week ago, and the Amazon carb didn't fix it. Eliminate that variable by going back to the first carb, that used to run fine. I've had terrible luck with people's cheap Amazon carbs on stuff, so no need to introduce yet another question to the mystery.

Get a small squirt bottle/can of pre-mixed 40:1 gas and try running it without fuel lines from tank hooked up. Just squirt the mix in the inlet to the carb. It should run. If it does the problem is with the tank/crankcase pressurization system, or the float bowl.

I suspect a needle/seat issue that is allowing excessive fuel to flow.

 

[Beemer]

This year I solved starting and running problems with very little effort on our Toro lawn mower, Giant Vac leaf blower and Echo 2 stroke leaf blower by replacing the carbs. Simple to do and only about $40 each. Even the dealers here can't cure the effects of ethanol laced gas by stripping them down once the problem starts .
You might consider giving it a try. It's cheaper than therapy!