Echo Chainsaw Issues

[CJM8515]

Just dragged out the echo CS450P saw today to do some light work. Noticed that even when warmed fully up if you nail the throttle it bogs for a sec then revs up? It looks hard to adjust the carb without removing half the case, but I do see a high and low adjustment? also the air filter is perfectly clean, so its not clogged. Removing it made no difference in the bog.

What should I adjust? High or low?

 

[Lassen Forge]

I would think it was some old fuel that started to gel in the carb rather than an adjustment issue. Pull the carb, clean it, flush the lines and tank, and put frens fuel in it. (If you can get 93 octane no-ethanol for your mix, use that - it helps a lot!)

 

[G_P]

Carb issue most likely. Pull and thoroughly clean the carb.
Dont forget to check the little fuel filter dangling in the tank. Sometimes they get all clogged up and then the saw cant get enough fuel at WOT.

 

[justme-]

Carbs don't need adjustment unless the environment changes... It's clogged from old fuel and corrosion. You can try cleaning it, be careful about getting solvent on the diaphragms as it will damage them. Also use ethanol free fuel especially when storing it or you'll end up with the same problem or worse in a month or two.

 

[stihlntime]

It is the carburetor diaphragms. Prolonged exposure stiffens them and they font flutter on the pump side. Its starving for fuel. Buy a 12.99 carb kit and replace the diaphragms. That saw runs at 13000 to 13500 rpm and the diaphragm must flutter at the same speed. Do not try adjusting carb. Take your carb into the shop so they can get you the right kit. Lots of You Tube voids on how to rebuild them. Nothing to it just get you gaskets and diaphragms in the right order. I rebuild them daily, Echo certified tech pm me if you need any assistance. Use 91 Oct no ethanol fuel. Don't let fuel sit in a unused saw over 90 days, dump the fuel and run dry.

 

[KraftwerkMk1Jetta]

Also make sure the tank is venting

 

[CJM8515]

I had figured it was the carb. Gonna have to take it apart and clean it and possibly rebuild it. There was zero fuel left in it actually and I used fresh 2 stroke mix I made the other day.

 

[redmondjp]

Oh come on guys!!!

The FIRST thing you do is try tweaking the mixture screws. Just the air temperature change alone (say, running at 50 degrees outside instead of 80 degrees) will require a mixture change. This isn't a fuel-injected, computer-controlled engine we're talking about here. Changes in temperature, humidity, elevation, and so on, all call for a mixture adjustment for optimum performance (which is why these EPA-mandated fixed settings are so stupid). Old-school drag racers would have a complete set of carb jets just to set their carbs for maximum performance for that day's conditions.

Get it idling, let it warm up a bit, and then try adjusting the low-speed screw first to maximize engine RPM. Then see if that helps the bogging. If it is either too rich or too lean it can cause it to bog during transition to the high-speed range.

Then do the same with the high-speed adjustment.

Always do this before tearing down the carb.

 

[anndel]

Does the gasoline you use have ethanol?

 

[pepi]

Chain saws have problems magazines have issues .

 

[brianh]

Tank vent could be an issue, more than likely its just a bit lean turn the needle screws counter clockwise you can only go about a half turn before you hit the stops ( I pull the caps off mine) counter clockwise is richer.

Another quick fix is rev it up and pop the choke if it is some crud in the fuel passages it can pull it out.

I use saws a lot, this has been the fix for me quite a few times. fuel mixture needs to be tweaked with seasonal changes, some newer saws do it automatically not too fond of that trend.

 

[Davefr]

I doubt it's the tank vent. That wouldn't explain a one second lag going from idle to full speed. If the vent isn't working it'll likely be seen as fuel starvation at full speed.

A one second lag doesn't sound like the saw has a major problem and I agree with the other poster that a small carb tweak could be all that's needed.

If you're saw has an adjustable carb there's nothing wrong with trying to richen the low speed needle jet about an 1/8 of a turn. The carb setting could be right on the cusp of being too lean. Just don't make random changes and remember the original positions. The owners manual should have the procedure.

 

[wayne55]

Just for the heck of it, before going to so much trouble, just turn the low speed screw about 1/16 to 1/8 turn counterclockwise.

 

[Wakefield]

Just noticed new ethanol free gas source about 20 miles away from me in Beltsville MD popped up on Puregas--but 116 Octane!

 

[CJM8515]

Just to clarify: Saw starts, runs fine. Rev it up and bogs slightly then catchers up. You cant go WOT without it happening. Go slowly on the throttle and its still there but not as much.

All gas here besides that stuff sold for 5 bucks a can at the hardware store and race fuel has ethanol in it. I use 93 octane always, supposedly they "claim" it has less ethanol content but IDK. Cant get race fuel easily either.

I tried the choke trick when I was having the issue, no luck. It was then I made this post. The saw had no issues when i got it and used it about 6 months ago, but now of course its colder. Went from about 70F to 50F.

As for the manual, gonna have to call echo and get one. Bought the saw used.

 

[stretch5881]

You can usually find a free pdf service manual on the net. Just tweak the carb like instructed and use non-ethanol gas. If you must use fuel with ethanol, drain the tank and run the carb dry before storage.

 

[stihlntime]

It's the diaphragms not an adjustment issue. You can try opening the L screw a 1/4 turn but it seldom works. I strongly advise using a tachometer to set your carb if you go cranking on the screws. I see six to ten cooked saws each month due to "self tuning". A half turn the wrong way can result in the saw being too lean. You don't need a manual to rebuild a carb, it's a simple task. Removing the carb will take longer than rebuilding it.

 

[CJM8515]

It's the diaphragms not an adjustment issue. You can try opening the L screw a 1/4 turn but it seldom works. I strongly advise using a tachometer to set your carb if you go cranking on the screws. I see six to ten cooked saws each month due to "self tuning". A half turn the wrong way can result in the saw being too lean. You don't need a manual to rebuild a carb, it's a simple task. Removing the carb will take longer than rebuilding it.

I can always try adjusting it first, but if that doesnt do anything then rebuilding it is fine. Its not hard, done it many times before.

 

[Davefr]

Rebuilding a carb is not just installing a rebuilt kit. It involves completely cleaning very passageway. (best done ultrasonically).

 

[CJM8515]

Rebuilding a carb is not just installing a rebuilt kit. It involves completely cleaning very passageway. (best done ultrasonically).

Not my first rodeo at all. I know how to clean and rebuild a carb.

 

[justtools]

Not my first rodeo at all. I know how to clean and rebuild a carb.

It seems all you are missing is the ability to know when to rebuild the carb.

 

[justme-]

Rebuilding a carb is not just installing a rebuilt kit. It involves completely cleaning very passageway. (best done ultrasonically).

Yes and no, never ultrasonic a diaphrams carb from these type engines, it causes damage to the check valves inside them.
To the op...buy and use the cans at the hardware store...its worth it of that's the only source you have for ethanol free gas.

Just a thought before anything else...noticed op mentioned change in temp...have you let the thing warm up before trying the trigger? I see a fair amount of customer complaints that are simply from expecting a chainsaw to act instantly like their car and fail to let it warm up. Had a blower in the shop Thursday with that situation.

 

[CJM8515]

It seems all you are missing is the ability to know when to rebuild the carb.

Man some of you can be so rude.

So if your motorcycle isnt running well when its 40F outside and you tuned it when it was 70F outside you immediately assume it needs a carb rebuild and not an adjustment??

I got the info I needed from the helpful members. Thank you guys. If you have nothignt o add you can keep your trap shut.

@justme-, yea it was warmed up fully at that point. Its probably an adjustment, but I wanted to ask first to be sure.

 

[mowersplus84]

Its most likely a bad fuel or a carb issue there are passage ways and holes that even some professionals don't know about.