Chain Saw Help

Good afternoon. For the past few days I have been trying to get my chainsaw started. It is an Echo cs-590, which up til now has been a very good saw. I've had it for about 5 years. I have fresh mixed gas in it, and have checked the spark plug gap & spark--both good.

What it does is this: When I first go to start it, I put on the choke and pull--"vroom." It then runs at idle for 5-10 seconds. Then it quits and will not restart. If I wait a few hours, it will do the same thing.

I have had the carb off & taken apart, checking diaphragms for dirt and all the jets for clogs with a fine wire.

The engine does not seem to respond to starting fluid sprayed in after the first 10 seconds of idle (air filter off). If I pull the spark plug after repeated pulls it comes out wet. I would think the spark is somehow cutting out, yet I have good spark when I check.

I can post pictures if required. This is the first time it has done this for me. Otherwise it has been a dependable saw. I cut maybe 3 cord a year with it.

Any insight would be appreciated. Thanks in advance. Dave

I would try a new spark plug.

Diaphragm could have a pin hole in it allowing it to pump excess fuel. Jim

If the spark plug is coming out wet it seems the fuel system is OK, have you tried a different spark plug? I have seen them spark just fine when outside the engine but won't fire under compression. I very seldom have spark plugs fail, but it's one of the easiest and quickest things to try when troubleshooting. I never use starting fluid when troubleshooting, I have a little squirt bottle with mixed gas in it, works best for me.

My Echo began not continuing to run and it turned to be a small split in the primer bulb.

Those little chain saw carbs really amaze me. When I have a problem a new kit will usually fix the problem. The thin diaphrams will look good, but will be stiff. I have a Echo CS 330, and Echos are good saws. Sounds like the coil is ok since you have spark. I would try a carb kit. Stan

Install a carb kit, fuel line and new spark plug. All of these items will give you problems.
Brian

Hi my name is Fat Dan;
My experience with a chainsaw is I built a cordwood house two stories 3600 sqf. any way back to your problem.
All of these ideas are excellent advice and any one of them can be the problem. The Idea is to start off with the cheapest and easiest things first when troubleshooting. Which order you attack your problem is up to you; with that I'll give you some more areas to look at for trouble.
Today's gas has ethanol in it which has water, when fuel is stored over time the ethanol separates and the water accumulates. When fuel separates the system will gum up vital parts, e.g. high/low jets, diaphragm, float valve, filters.
Whisker in the spark plug: a whisker is when there short between the electrode and anode (piece of dirt in the gap). A bad spark plug can have broken porcelain, lose tip, fouled out or just used too much when it was new.
If the cloth type filter gets water wet it will not allow proper fuel flow.
USUALLY - If you take the carb apart you will find varnish left by the fuel residue has things block up. Simply by you removing the parts and cleaning them then replacing them gives the saw half a chance.
Hoses and gaskets: these little saws run on vacuum check lines and gaskets to and from and in the carb. Closely inspect the diaphragm gaskets/flapper-valves make sure they are clean and flexible.
A bad coil (unusual) can cause intermediate spark.
Spark Plug wire has short - pull over in a dark room and look for external spark.
Good Luck



Old pictures but gives a better idea of construction.

Check to see if there is a spark arrestor screen in the muffler. They tend to get clogged and keep them from running. I just take them out of mine.

my CS-590 did something similar, and it turned out to be a very small split in the fuel line from tank to carb.

I think before I did anything I would determine if the problem was the spark or the fuel. You might pull the plug and ground it and see if it creates a spark. You might also use a little starting fluid in the carb to see if it tries to start.

My guess would be it's flooding, bad diaphragm, needle valve out of adjustment, damaged, trash under the seat, seat blew out during cleaning.

Try disconnecting the kill wire, pull it away where it can't possibly touch anything, see if it changes anything.

Did you check the tiny fuel screen inside the carb? It filters all gas in the channel that goes to the fuel inlet needle. Very common to plug, especially if cutting wood with a dull chain that makes a lot of dust instead of chips.

So is the short logs seasoned before you lay them and is that just plain mortar or concrete in
between. Also do you have termites where that building is ?

(quoted from post at 14:07:32 04/13/20) So is the short logs seasoned before you lay them and is that just plain mortar or concrete in
between. Also do you have termites where that building is ?

Click to expand...

Some good questions.
All the wood had been peeled and seasoned then prior to installing they were soaked to expand the fibers. I eventually only used cottonwood in the wall and white spruce for the posts, beams, caps and lintels. The reason I used cottonwood was it has more random fibers as apposed to tree rings which can wick heat easier. Cottonwood is technically a hardwood and once properly seasoned it is hard to drive a nail into.
Wall:The wall is actually three walls in one, first off the logs are two feet long and set on a footer two feet by one foot thick w/ five strands of #5 steel 6-sack.
Mortar: The mortar is made with soaked sawdust in the mix to retard the set so it doesn't shrink away from the wood, that's also why the wood is soaked prior it installation.
On the footer I put a 6" x 6" berm of mortar on the outside perimeter and a like berm of mortar on the inside perimeter which left a foot or so gap between berms that I filled with limed sawdust. Once the mortar and sawdust were in place logs were placed about 3-4 inches apart. Rinse and repeat.
Alaska don't have termites yet but Cordwood construction dates back over a thousand years manly were used for out buildings and barns.

Excuse the bright reflection off the top of my head but the picture shows a little of what I've been talking about.

hello you did not say when it was run last so I would like to add one of my thoughts I had a stihl saw sit all summer one time and the mud dobbers plugged up the exhaust outlet it acted the same way just a thought

As a follow-up to everyone who responded, I took the suggestion of using gas instead of starting fluid. I poured about a teaspoon down into the carb body/choke opening. Then after a few pulls it fired and would even run at idle for maybe 10 seconds. Took out the NGK plug and put in a champion--made no difference, so put the NGK plug back in.

I took a look at the Walbro carb linkage and found that the choke lever was binding/hitting on the inside of the air cleaner assembly (a piece of plastic). This prevented the choke from fully closing, and also did not allow the lever on the choke plate shaft to "latch" with the throttle shaft to "set the throttle." This is unrelated to the current problem but does explain why the saw was always hard to start when hot, as the choke is supposed to hold the throttle open about 1/4 until the handle is squeezed, releasing the choke and the throttle at the same time. I ground the plastic away in the offending spot with a rotary grinder and after some trial and error can now set the choke and throttle like I should.

Anyway, I can now get the saw to reliably start, but it will only run at half choke, and then only for 20 seconds or so. After squeezing the throttle lever and dropping to low idle it will stall. So I am thinking there must be some obstruction in the carb idle jets still in there and/or a pinhole leak in the gas lines that is interfering with good fuel flow and/or a diaphragm problem (or all three). I tried it with the fuel filter removed and that made no difference, so I do not think it is the filter, although it is the original (5 yrs old) so probably time for replacement anyway.

It will be a few days yet when I get back to this but will post my results if/when I make any progress for the benefit of anyone with a similar problem. Thanks to everyone with the good suggestions. I learned something about cord wood houses anyway. Pretty interesting--but looks like a lot of work. Dave

As a follow-up to anyone reading this in the future, the problem was that the impulse hose that runs from the crankcase to the carburetor had become disconnected from the crankcase. As a result, when at idle, there were no "puffs" of pressure or vacuum going down this line, so no fuel was being pumped. The problem did not occur at start-up because the carb vacuum at full or half choke was enough to pull fuel all the way from the tank, even without impulse power to the fuel pump. Now the saw is at least running (and will rev fully), but does not hold a steady idle. I am thinking this is a tune-up problem and will be multiple attempts at fine carb adjustments to get it right. New diaphragms are on order; a new fuel line and impulse line as well.

I discovered this by removing the spark plug and the carburetor. Pulling the start cord while on the workbench produced plenty of vacuum at the crankcase inlet/carb outlet opening, but no vacuum could be felt at the impulse line which hooks to the top (pump) side of the carb. Replacing this line with a small syringe connected directly to the carb impulse connection and pumping by hand brought fuel to the carb. Upon disassembly sure enough, there was the impulse hose, dangling there, disconnected and doing nothing.

Thanks to everyone that contributed ideas. Dave