Discussion in 'Chainsaw' started by Andyshine77, Jun 24, 2016.
Looking at the video again it looks like he has the new vented hood. He did say it is a new saw.
Andre, I have not experienced the same hot start problem as you but I don't cut much in the heat. So my 2260 may indeed have the same problem. I usually run AV gas and maybe that makes a difference.
I know when fuel gets real hot air can and will leak into the system but fuel will not leak out causing vapor lock. I witnessed this on my old Ford tractor, it about drove me crazy for awhile. When I looked into the fuel tank I would see bubbles where the fuel line attaches to the tank. When the tractor got very hot it just ran out of gas. The leak was around the sediment bowl gasket. I never saw or felt any gas leaking out. Maybe air is leaking in. Your saws symptoms and my tractor are the same. Maybe a small tie wrap on the fuel lines might help, easy to do. I am just thinking out loud here.
Another thought is saws with primer bulbs have more connections for air to leak in.
That's what I am talking about!
I guess not as you don't have a auto tune saw. Steve
The fact is these auto tune saws are running too lean in hot weather thanks to EPA emission bs.
I was actually wondering of AV gas might make a difference, although that's not a realistic long term solution for most.
That would be easy enough to try out. Bypassing the primer bulb would be as well.
Isn't AV gas higher octane? Wouldn't that hamper the performance being a cooler running fuel? Seems like you would be shooting yourself in the foot buying a high performance saw to feed it fuel to keep it from performing to its potential. That is if I understand it correctly.
Gentleman I always let my saws idle a bit inbetween long cuts and before shutdown, it's my normal operating routine.
I tried starting the saw with the throttle wide open off camera it wouldn't even stumble, the only way to get to stumble was to not go near the throttle.
I started a thread on vapor lock. I want to gain a better understanding. Please don't think I am trying to poke fun at your situation. I will test my saws today and see if I can cause a vapor lock and to see if I can remember create it. If so I think it would be a starting point on finding ways to prevent it. If that is even the problem with your 562.
There is no air leaking in - the fuel is hot enough to boil/vaporize. Those bubbles are vapor coming out of the liquid fuel. Anything that reduces the pressure on the fuel makes it boil/vaporize more esily, such as the fuel pump or purge bulb pulling on the fuel line, or the carb venturi doing the same.
I don't think the purge bulb causes the problem, but it won't work when the fuel is close to boiling. The only thing I've been considering is if having more fuel volume is an issue, and then the purge bulb might be a negative - but I don't see how that would work.
The Poulans I've modified had purge bulb s to start, but the larger carb I used had no port so they got removed. Thos saws all vapor lock just like any other so I doubt it's an issue.
Me too - several years ago: http://www.arboristsite.com/community/threads/hot-starting-vapor-lock-issues-e10.262628/
Not a problem.
To add some more input, I often cut in the summer when it's hot, I have never had an issue like this with any other saw I've owned.
I have thought of eliminating the primer setup to see what that does, it was actually my first idea.
With that said nothing special should be required to start or operate a new tool, and no modifications should be required. It's simply not acceptable IMHO.
It's not the octane that interests me. IIRC, AV gas has a higher vapor/boiling point by design.
I'm heading in a few with the Echo to finish what I was doing last evening. I'm going to run the balls off the saw, and sit it in the sun for a few and see what happens.
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You are correct the fuel is turning to a vapor due to lower pressure. However, I still say it was leaking causing the lower pressure because when, on my tractor, I installed a new gasket the vaporizing stopped and the tractor ran fine. I think we are in agreement but you expressed it more accurately.
LOL, I have an early 1950's Ferguson TO-20, so yeah I get where leaks are always an additional possibility there!
If fuel was leaking by the needle and seat, relieving pressure on the system, that would allow the fuel to vaporize-boil?
Edit: Mine is a 1960, 801, 4-wheel drive.
So basically the check valve is failing. I told Brad yesterday that the fuel was being forced back into the tank. This could make one believe the fuel in the tank is boiling, when in reality it's not.
Just finished running another saw in the same conditions as the 562xp, let it sit in the sun and everything. I'll put the video up later, if you all interested.
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But how does this explain the purge bulb? You can pump that thing all you want and it will pull no fuel.
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