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View Full Version : Echo PB-650 having odd full throttle problems


genesis215
04-12-2010, 06:05 PM
I have a 2003 Echo PB-650 that's been having issues all of a sudden. It starts up with 1 or 2 pulls, and idles great, but it has very erratic operation at full throttle. It kind of sputters and shakes, and sometimes it's randomly cuts out almost, and then goes back up to somewhat normal, but not the full screaming sound that it normally has. The muffler has practically zero carbon, and the spark plug looks normal, with only light tan deposits. Also the fuel filter was just changed. It sometimes doesn't do it, but it seems to do it the most when it's hot outside. I tried taking off the gas cap in case the tank wasn't venting properly, but that didn't affect anything. I am using Shell 93-octane gas with Amsoil at 50:1, and 1 oz. of Seafoam per gallon. All my other stuff runs great. Any ideas?

genesis215
04-14-2010, 03:00 PM
Bump. Any ideas at on what might be going on? It seems to do it only when it's above 75 degrees out, and when it gets up to about 85 it won't hardly get up to half throttle.

morgaj1
04-14-2010, 04:38 PM
Have you checked the coils? Might be a spark issue.

genesis215
04-14-2010, 06:24 PM
No I haven't, but that kind of sounds like it since it only does it when hot out. I don't know exactly how to check the coil, could you tell me how? Thanks.

morgaj1
04-14-2010, 07:08 PM
Here is a good You Tube video showing how to test the coil on a chainsaw. If it shows good spark when cold, wait until it starts dying and test it again. If you find that it is the coil, get the dealer to replace it. Echo has a lifetime warranty on coils, and I am assuming they did in 03 as well. Hope this helps:

http://www.youtube.com/watch?v=L7WNBDRG4C4

genesis215
05-10-2010, 11:10 AM
Well guys I've checked the coil, and it is fine. I disconnected the kill wire like in the video, didn't change anything. I am wondering if it is the tank vent, or even a fuel line. What do y'all think?

morgaj1
05-10-2010, 12:32 PM
Try this - Crank it and run it until it starts sputtering. While it is running, take the gas cap off. If it clears up and runs fine, then the gas cap vent is bad.

Merkava_4
05-10-2010, 05:17 PM
. . .but it has very erratic operation at full throttle. It kind of sputters and shakes, and sometimes it's randomly cuts out almost, and then goes back up to somewhat normal, but not the full screaming sound that it normally has.

Echo says you have a Walbro WYK-150 carburetor. The Walbro manual shows a high speed mixture needle on the side; do you see one on there? It'll look like a screw head with a spring under it.

markahurley
05-10-2010, 06:12 PM
i had the same thing happen on mine. kept dying out at full power--and got worse and worse. mine ended up being a carbon build up on the exhaust screen. you can take the screen off, or if yours is like mine was and is too rusted to remove the screws, just punch a few holes in the screen. with the carbon build up, it can't breathe, and will choke itself out.

ed2hess
05-10-2010, 10:17 PM
I got two of them older than yours....mine did the same thing and I had to get an adjustable carb and that fixed the problem. I tried everything including putting new seals on crank shaft. In the early years NO adjustment on the units. I guess you tried it with exhaust off and ports are clean...usually those units never had carbon problems. I even pulled the head and checked those transfer ports and they were good to go. I didn't test compression put I bet these units are running pretty low due to wearing down the rings and sleeve surface....

genesis215
05-12-2010, 10:11 PM
Ok, I've got an update. It was 85 today, so it was good for a test. I tried starting it up and letting it idle for a full minute before touching the throttle. Then after the warmup I tried throttling it, and it went right up, and stayed at full screaming rpm's with no trouble. I shut it off for about 10 minutes, started it back up, and tried full throttle again, and it kind of ran slow, and hiccuped, so I let off, and let it idle about 10 seconds. Then tried again and it was fine again. My conclusion is that the carb is probably lean or something, hence the fact that my friend's PB-651 can go full throttle immediately, whereas mine takes about 30 seconds to a minute before it can take any throttle. Also my friend's 651 will die if the choke is not turned completely off immediately. And mine has to run for 5 seconds on full choke before gradually opening it up in increments. If it turn the choke off all the way after the 5 seconds, it usually dies.

What do you guys think? Could I put a WYK-192 carb from a PB-651 on to replace the WYK-150 that is on my PB-650? Somewhere on here I read something about the PB-650's being set very lean from the factory, and needing warmup, and that the PB-651 had a richer-set carb, so no more warmup needed. Don't know if this is true, but it makes sense.

Any thoughts would be appreciated.

Merkava_4
05-13-2010, 06:25 AM
What do you guys think?

I think you should pull the tamper plug off the rotary valve and gain access to the inner
idle mixture needle. I also think you should look to see if there's a high speed mixture needle.

genesis215
05-13-2010, 06:30 PM
Ok guys, I just looked at the sticker on the engine, and I actually have a 2001 PB-650H, not a 2003. My carburetor number is WYK-180, and it has no adjustment needle. What I am planning on doing is first replacing my NGK plug with a E3 diamondfire plug, and see if that helps. Several guys on here have highly recommended the E3 plugs, saying that they increased power, and decreased warm-up time dramatically. If the plug doesn't solve it, then I will just go ahead and replace the carb with a adjustable WYK-192. I will let you know the result.

rob7233
05-13-2010, 07:22 PM
Try something inexpensive first. Many full throttle weirdness comes from a poor seal at the fuel tank. Replace the plug seal and all the fuel lines on the blower. Echo sells them in a kit for 10 -15 dollars. It'll take you about 15-20 minutes to do the repair. If the fuel lines don't fit good and tight now along with the fuel cap, then that's likely your problem. Look for the Horses before the Zebras. Let us know how it goes...........

ed2hess
05-14-2010, 09:18 PM
Try something inexpensive first. Many full throttle weirdness comes from a poor seal at the fuel tank. Replace the plug seal and all the fuel lines on the blower. Echo sells them in a kit for 10 -15 dollars. It'll take you about 15-20 minutes to do the repair. If the fuel lines don't fit good and tight now along with the fuel cap, then that's likely your problem. Look for the Horses before the Zebras. Let us know how it goes...........
I would have thought that a leak on that seal would only spill gas and not affect how it runs. I have seen them get worn and the lines shrink to the point that gas spills out. So you are telling me I need to keep those sealed up better or the unit won't run at high revs?

topsites
05-14-2010, 09:23 PM
It's all good, my srm-260s trimmer takes at least a full minute of a sputtering
warm up before I can get WOT out of it and it has done this for many years,
so my attitude is if it works, don't fix it.

rob7233
05-15-2010, 10:53 PM
I would have thought that a leak on that seal would only spill gas and not affect how it runs. I have seen them get worn and the lines shrink to the point that gas spills out. So you are telling me I need to keep those sealed up better or the unit won't run at high revs?

What happens is that it won't draw up enough fuel for a higher rev demand. It may idle okay but try to die out when pressing the throttle but it can do other weird things depending on the degree a the leak. I just fixed an Echo edger for a buddy of mine (after) he spent $100 on a new carb and it still didn't work right. A new spark plug and tank plug/fuel line kit (totaling less than $15.00) later, he said it never ever ran this good.

Afterward, he walked away with a smile on his face so big, that even a plastic surgeon couldn't remove it!

morgaj1
06-14-2010, 10:39 PM
Any updates?

genesis215
06-15-2010, 09:29 PM
I put the E3 spark plug in, and it has decreased the amount of time I need to let it warm up by about 2/3rd's. It now just needs 20 seconds or so and it's ready to go with no problems. Before it was about a minute. I am very pleased with the results of the E3 spark plugs. When the plugs on my other stuff go, I know what I'm getting!

Ruben Rocha
06-16-2010, 03:14 PM
Ok guys, I just looked at the sticker on the engine, and I actually have a 2001 PB-650H, not a 2003. My carburetor number is WYK-180, and it has no adjustment needle. What I am planning on doing is first replacing my NGK plug with a E3 diamondfire plug, and see if that helps. Several guys on here have highly recommended the E3 plugs, saying that they increased power, and decreased warm-up time dramatically. If the plug doesn't solve it, then I will just go ahead and replace the carb with a adjustable WYK-192. I will let you know the result.

I believe this unit does have a hi-speed screw. It is kinda hidden. it is a screw recessed in a hole about 3/16"wide on the carb.
You will need a very thin screwdriver.
Just turn it counterclockwise just a tad.
I found out from my dealer.

genesis215
06-16-2010, 08:34 PM
My carb # is the WYK-180. I looked up the IPL, and my PB-650H doesn't have a hi-speed needle. The PB-651 with it's WYK-192 carb does.

Here's the links:

PB-650H carb - http://www.partstree.com/parts/?lc=echo&mn=PB-650H++S%2FN%3A+05001001+-+05999999&dn=6944
PB-651H carb - http://www.partstree.com/parts/?lc=echo&mn=PB-651H++S%2FN%3A+06001001+-+06999999&dn=6946

CT18fireman
06-17-2010, 10:27 PM
I have PB755s and they have the wyk-192. There is a needle valve it has a plug on it. Just today I carefully drilled the plastic plug on one to get to the needle as part of a carb cleaning. Worked great back to full power.

There was a guy posting a while ago who told this elaborate story about how he buys echo, uses them for a year, they start to run poor, he has a dealer tune them and then sells them. Why? Just do a good carb cleaning, including needle valves or at the most replace the carb for $50-60.

I run echo mix and I have never had any issues with carbon in the exhaust port or screen.

I would be willing to bet you could swap the 192 onto the blower.