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ECHO CS-620 PW intermittent no start when hot

TurbineDoc

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Hello my 1st post this forum, I am a veteran of many Diesel truck forums under same user name.

I have searched until I'm feeling like I have been drinking from a fire-hose; :eek: there is soo much good information but even with the search engine, the is nothing quite matching what I'm experiencing.

I am a member of a Christian Disaster Relief Ministry team where we volunteer & assist with recovery & debris removal following Wind, Flood, & Ice storms I moved into a "professional saw" from the Sthil MS290 & Poulan 3450 saws I have had for decades, into an Echo CS-620 PW at end of storm season 2020.

It has been a great saw thus far, all stock in a call out 3 weeks ago; a small area impact tornado in Moss Point MS the saw after fueling up refused to restart, after about 10 minutes I was able to restart it no issues for the rest of the day, I had a similar event happen last year.

Common denominator both events was high heat index days +100-105F with 95+% humidity, saw is fine now no issues, I still have warranty on the saw do I need to have them look at it or is this a temperature driven event, just live with it?

The trees we normally encounter are sized from saplings to 60" across that take cuts from both sides with a 28"-32" bar, varieties as we find them cedar, pine, live oak, water oak, magnolia, "pop-corn" (Chinese Tallow) sometimes down on ground or on houses, or ones we have to drop that are twisted or broken off at tops. The larger older trees often are rotten in middle with water in them that "gum up" bar/chains with "mud & pitch"

I run 50:1 "true fuel" or similar pre mix, or 50:1 non eth 87 octane g/o mix I add Stabil to when I mix it, I keep the oiler turned up to max factory allowable adjustment, I've read here that more oil is possible after making some "field modifications" to the limiter.

I have also seen several threads on opening up the muffler on other Echo models, would opening mine up assist from what appears to be an overheat condition?

How much is too much open and do I need to live with this until warranty period expires?

I had considered finding a "used but good" older model muffler from say a 590 and modifying/running that, and saving the original muffler for reinstall if I need to have warranty work completed, is that worth looking into as well ?

The week before I found this site, I just ordered an Echo CS-7310 PW looking for "more power" maybe now I realize with some tweaks the 620 I have now is plenty, my 620 came with a 24" chain/bar, it pulls a 28" ok but bogs down a little on the really big trees. The 7310 due in next week will have full wrap handle & 32" bar/chain, they had a standard handle 7310, but with some of the places we need to work around the full wrap handle comes in handy.

Tim aka Turbine Doc
 

Ford3000

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Welcome to the forum. I think the first thing to do would be to take the muffler off your saw, and pull the starter over slowly, look at the piston as it comes up to the exhaust port and tell us if you see any scoring, there should be none, if there is then definitely do not try to start the saw again. I think given you were cutting up to 50" diameter in very hot weather using a 50:1 mix you may have scored piston and cylinder, these saws really need those limiters removed to allow the fuel jets to be properly adjusted to provide the engine with more fuel.
Let us know what happens, take some pictures of what can be seen in through the exhaust port when you remove the muffler, look at the cylinder walls too as much as you can again noting any scoring.

Example of how to remove the muffler and what to look for
PLEASE get someone to look at your incoming 7310, these saws are all restricted to in order to meet the EPA emission standards,
so they could and do come set up lean from the factory, lean means they are getting too little fuel into the engine which for two reasons causes them to heat up and destroy themselves, first is, less fuel means less oil to lubricate, secondly the leaner the engine again from less fuel than optimal creates a hotter burn which again causes melt downs. It can all be avoided by having someone remove the restrictors and adjust the carb, I would also recommend using 40:1 mix instead of 50:1.
 
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Kiwioilboiler

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The "chickanic" on YouTube is scathing of trufuel and its consistency. Check the vids out so you are aware of the concerns. Can't verify for myself because we don't get it here.
 

Clarkbug

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Hello my 1st post this forum, I am a veteran of many Diesel truck forums under same user name.

I have searched until I'm feeling like I have been drinking from a fire-hose; :eek: there is soo much good information but even with the search engine, the is nothing quite matching what I'm experiencing.

I am a member of a Christian Disaster Relief Ministry team where we volunteer & assist with recovery & debris removal following Wind, Flood, & Ice storms I moved into a "professional saw" from the Sthil MS290 & Poulan 3450 saws I have had for decades, into an Echo CS-620 PW at end of storm season 2020.

It has been a great saw thus far, all stock in a call out 3 weeks ago; a small area impact tornado in Moss Point MS the saw after fueling up refused to restart, after about 10 minutes I was able to restart it no issues for the rest of the day, I had a similar event happen last year.

Common denominator both events was high heat index days +100-105F with 95+% humidity, saw is fine now no issues, I still have warranty on the saw do I need to have them look at it or is this a temperature driven event, just live with it?

The trees we normally encounter are sized from saplings to 60" across that take cuts from both sides with a 28"-32" bar, varieties as we find them cedar, pine, live oak, water oak, magnolia, "pop-corn" (Chinese Tallow) sometimes down on ground or on houses, or ones we have to drop that are twisted or broken off at tops. The larger older trees often are rotten in middle with water in them that "gum up" bar/chains with "mud & pitch"

I run 50:1 "true fuel" or similar pre mix, or 50:1 non eth 87 octane g/o mix I add Stabil to when I mix it, I keep the oiler turned up to max factory allowable adjustment, I've read here that more oil is possible after making some "field modifications" to the limiter.

I have also seen several threads on opening up the muffler on other Echo models, would opening mine up assist from what appears to be an overheat condition?

How much is too much open and do I need to live with this until warranty period expires?

I had considered finding a "used but good" older model muffler from say a 590 and modifying/running that, and saving the original muffler for reinstall if I need to have warranty work completed, is that worth looking into as well ?

The week before I found this site, I just ordered an Echo CS-7310 PW looking for "more power" maybe now I realize with some tweaks the 620 I have now is plenty, my 620 came with a 24" chain/bar, it pulls a 28" ok but bogs down a little on the really big trees. The 7310 due in next week will have full wrap handle & 32" bar/chain, they had a standard handle 7310, but with some of the places we need to work around the full wrap handle comes in handy.

Tim aka Turbine Doc
If you have a good dealer, I would suggest starting there since the saw is still in warranty. Especially since you just bought another saw I would hope they would look at your current one.

It also sounds like a pretty limited problem, maybe almost like a vapor lock kind of thing?

Swapping the muffler for one more open or adjusting your oil ratio will mean you need to pull the limiters on your carb. I think everyone here agrees that's a very good thing for longevity of your saw, but if you need your warranty that could pose an issue.

Like ford3000 said, checking your piston is a good thing to do for peace of mind and to see if any scoring is taking place.
 

TurbineDoc

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Thank You for all the feedback, I will pull muffler later today just to see if any issues are present, to further expand on the scenario, when it happened in past it almost acted as if a no spark situation, pulling effort to start was no different, but no change either when using compression relief, other than a sometimes "hit" like it wanted to start but did not resetting the compression relief.

I pulled plug to see if fouled, a couple of times plug was wet & smelled of fuel as if a flooded saw, so possibly a vapor lock issue.

Disconcerting that Tru-fuel or other "store bought" mixed fuel may be a problem area #1 it is expensive, and second we use this fuel on our disaster relief trailer to preclude having to mix fuel in the field.

Is there 1 pre blended fuel recommended.

On oil mix ratio's as I recall 32:1 mix was what I used back in the day with my Poulan saws how sensitive to mix ratios are these newer saws, would going with say 40:1 be that big of a change other than possibly fouling of the plug?

Thank You again in advance.
 

Ford3000

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Don't like the sound of the same pressure on the starter cord with the decomp pressed in. More oil gives better protection, especially when you need it under hot conditions, but you have to tune your saw accordingly, as that more oil leans out the fuel and this causes lean running, so generally if you go 40:1 tune your saw to four stroke when out of the wood and clear up when under cutting pressure. Not every saw will be too lean with a 40:1 mix, it simply depends on how it is tuned before hand, some will still be rich enough as they could be tuned too fat for 50:1, others 40:1 could give them the push over the edge into running too lean.
I use Aspen 2, its premixed at 50:1 , you also get Aspen 4 which allows you to mix in your own two stroke oil as Aspen 4 does not contain two stroke oil at all, Aspen fuels have a long shelf life which is why I use it as I only use saws intermittently, lots of Germans use it and have had no issues with it, it is expensive though, they can not use pump gas by law.

You didn't happen to go from Tru-Fuel to a pump gas mix, I find with Aspen I simply can not, my carb needs adjusted to do so, some have reported needing less of the likes of Tru-Fuel and more standard gas if its used, If I remember correctly I needed to add more aspen by screwing out the carb needles than when I used standard mixed gas, so I would be safe if someone accidentally put mixed pump gas in my saw, it would have too much fuel.
 
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TurbineDoc

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I took muffler off yesterday, pictures turned out like crap or I would post them, nothing in the cyl looked alarming, rings and piston also looked good, no heavy carbon deposits, so I'll be taking to my Echo shop as suggested since it is still under warranty and see if they have any thoughts.

Ford3000 I'm at sea level with the sea or close to it or routine call outs are TX, LA, MS, FL Gulf Coast I did run out of "canned fuel" and swapped to non eth 50:1 the "limbs" from a broken live oak are what I was working on when saw got temperamental. The 2nd picture was one of the "big-uns" we worked the day before.

1689620861622.jpeg
 

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Ford3000

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It is a good idea to take the saw back as it is under warranty. Might not find the issue in a shop though as it may take some heat and pressure from cutting to bring about the issue again.
Your dealer will probably tell you to stick to 50:1, I would not, its too little oil in my opinion for when your in the heat of battle on a hot day. If your dealer won't tune your saw to run at 40:1 then get someone competent to do it for you. Oil is the only thing that keeps your saw alive and from burning up, saying that a dull chain and the saw engine racing fast because its not cutting won't ever help and has killed many a saw. 28 and 32 inch bars are way too big for that saw unless everything is tuned, rakers are not too low and you don't push through cut after cut without allowing the saw to cool down, not a good idea to run a saw and just stop it straight after the cut, let it idle for 30 seconds on the ground while you do something else, that gives it a chance to cool from the air pulled in by the fly wheel.
There could be lots of reasons, or a combination of small things that lead your saw to be hot or refuse to re start. Your still in good standing as long as there is no piston or cylinder damage. A good tune on the rich side and use a known good fuel with a sharp chain and see how it goes, never underestimate the ambient heat either, hot days are sore on engines, and being at sea level means your saw will need the most fuel ever, as you rise in altitude you have to use less fuel to keep the engine running.

Let us know what your dealer says, and if you can get another muffler and modify it do so, let the heat and burnt gasses out in order to let more mix in, the saw will breath better, a picture of the plug might help too, it will indicate if the saw was ran hot or not.

This is only my personal opinion, but I have read of trouble with saws running Stihl Ultra two strok oil in the gas, it was not coating the bottom end of the engine and it was not burning up the top end and leaving a mess. I use Husqvarna XP+ and my saws do seem to run better on it. I run it at 40:1, I tired Castrol 2 T Racing and it was like grease, stopped that right away, but in your heat it might be fine and even at 50:1. I understand you use TruFuel, is that 50:1 / 2% or do they have a different mix like 4%, thought I read that somewhere.
 
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TurbineDoc

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So I took my saw to Echo shop, they found nothing wrong with it, the shop tech said Echo's are prone to flooding, and use minimal choke or not at all if saw has been run already.; also no compression relief use after saw was warm.

I had to laugh when I 1st tried to take it to the shop , a sign on the door saying shop will be closed all weekend until fishing rodeo was over.

The part that had me grinning if you have seen & remember the line in movie "My Cousin Vinny" where he had to go to a thrift store to get a suit, because "the whole store had the Flu" and was closed...ergo the whole store went fishing 🤣🤣 .

I also read up or watched video on fuels more especially True Fuel basically do not use it from what I gather here:

The tech said the 27" bar on the CS-620 even though in the published capabilities is probably at upper limit of the saw, and may need to have some carb adjusting if I continue to have issues.

They saw has only "not started" 3 times in the last 2 years where I have had to switch to a different saw until it felt like restarting.

Last weekend we downed 10 trees 12-20" avg. no issues running with the 24" bar it came with; it was a 104F/ 100% humidity day, I was using my own 89 octane no E gas & 50:1 2-stroke mixed fuel, not "canned fuel" maybe just a fluke for those no starts.

I asked about taking red caps of and adjusting carb and warranty ( don't damage the red caps) 😉😉 and I if decide to run a modded muffler retain the original muffler "just in case" I need to bring in for warranty claim. Now Im looking for a "used but good" donor muffler to modify.

My new CS-7310 PW 32" bar just arrived so I think what I will do going fwd run the 7310 on the "big stuff" with the 27 or 32", and run a 20 or 24" bar/chain on the 620

I got a decent deal on the 7310 .. $1030 out the door, I did have to wait for the full wrap handle to arrive, the dealer had a standard 7310 in his shop, I wanted the full wrap handle setup so he ordered that, it never came the distributor botched the order, so my dealer ordered the wrap handle kit for no extra charge, and another PW-7310 whichever arrived 1st would be what I would get, apparently there is a backlog on the standard 7310, and also the 7310-PW with wrap handle option.
 

magicrat

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I use VP 40:1 to one if I don’t mix my own. And when I do mix my own I use only non-ethanol fuel. Never heard anything negative from anyone about VP.
 
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