homelite super ez won't restart hot... sort of

[Just_A_Grunt_1978]

Ok, so I got me a homelite super ez auto I have been messing with. It starts up pretty good cold. Cuts good, doesn't die on the idle, cuts fine. If you shut her down and turn her right back on, she'll start on the first yank. But if you let it sit maybe 5 min and try to start it back, it has to completely cool down before you can restart it. Any ideas on what this could be ????

 

[jrs_diesel]

Vapor lock perhaps?

 

[Okie]

First install a new correct spark plug properly gapped.

If that is a no go.

After the saw gets warmed up (as you say hot) set it down and see if it continually idles good for at least 1 minute?

I own several EZ types and most all of them require a full choke with enough pulls to get a promise then half choke to get a run with the throttle button locked to fast idle even when the saw's have been warmed up then let them rest little while.

Also next time try giving it a short pull re-start with the compression release off. Be ready for this, bring it up on compression stroke, stop let the rope re-tract then pull agressively. If it starts easier by not using the compression release this is one sign of weak compression (more compression needed to get a start when hot) or a vacuum leak.

A common source that will cause such is the 4 nuts holding the cylinder to the block are not tight. If you can turn one nut 1/4 turn or more they are all loose and the cylinder base gasket is leaking. If tightening all and it still has the issue it needs vac/pressure tested to see if the gasket is bad.

Do you have a chainsaw compression tester (for small cc engines that reads correctly) and a vacuum/pressure tester for chainsaws?

If none of the above flys, pull the muffler and look at the piston or if the saw starts better by not using the compression release examine the piston cylinder for cancer. (compression will decrease somewhat when a chainsaw gets hot, especially if compression is at the low end on compression when cold which is less than 100-120# or so for a EZ. They will usually have 140 or more when cold, but get little aggravating to start and cut good when hot if compression is 100 or less COLD.

 

[HarleyT]

Yes, look at the piston first.

 

[svk]

Vapor lock perhaps?

I would agree.

Check around the flywheel and cylinder fins to make sure arent full or dirt/grease/grass. That will make the saw run hotter which will exacerbate hot start issues.

 

[Just_A_Grunt_1978]

its really weird. It will idle all day. I was working on some other stuff up at the garage, and decided to do an experiment. I chucked half a tank of gas in it, started it and threw it up on a trailer and left it running. For like ten minutes. Maybe even 15. And then I went turned it off, turned the switch back on, pulled it once and it started. Turned it back off, left it maybe five minutes, went back to pull it and not even a pop. But it feels like it has awesome compression when you try to pull it without the compression release engaged. I cut a bunch of good sized beach with the saw and it cuts good. I also de-limbed some pine trees. I have thought about gapping the spark plug a bit wider, but maybe a new plug would be the answer. Also, it looks like who ever had this saw used it like three times and sold it to me. So any dirt thats on it is from the little bit of cutting I've done with it. I almost feel bad about using it. I have an old beat up one I'd like to use instead to do actual work with, but it has pretty close to the same symptoms. I wonder if I'm just not starting it correctly when its warm??? But I'll try some of this stuff and report back! Thanks for the suggestions.

 

[jrs_diesel]

It sounds more and more like vapor lock. That it restarts right away indicates to me that the fuel has not had enough time to boil/vaporize in the carb and fuel lines.

Once it sits for a few minutes and the fuel gets hot from the heat coming off the cylinder, the fuel turns into a gas which subsequently can’t easily be drawn through the carb and then the saw won’t start again until it cools down enough for the fuel to condense back to liquid.

As long as it’s running, the fuel is moving, as is the fan is moving air for cooling. Vapor lock doesn’t happen until after shutdown, it’s due to gasolines low boiling point and high vapor pressure.

Try this thenext time it does it, use a fan and try to cool it down and see if it will restart.

 

[undee70ss]

Richen up the “L” mix screw a little bit. When set to lean, will also cause hard starting. Are you using throttle lock on restart?

 

[Old2stroke]

As above. If a saw won't start hot with a couple of pulls with the throttle closed, set the throttle lock to partially open the throttle and try again. Many 2-stroke engines do not like to start with a closed throttle when hot and usually will NOT start with it closed when cold. If you set the engine idle speed as high as possible without the chain moving, it sometimes helps with hot starting without using the throttle lock.

 

[Okie]

Richen up the “L” mix screw a little bit. When set to lean, will also cause hard starting. Are you using throttle lock on restart?

Richen by going ccw on the low mixture jet by maybe 1/4 to 1/2 turn.
If the idle drops too much as you richen up, set the idle adjust little higher CW. (make sure you are on the correct ones and pay attention so as you can re-set them as they are now.. The L,H and LA are marked on the carb and also maybe on the air box.

Also try starting the saw cold then kill and dump out all the old gas, re- start the saw and let it set and idle until it runs the carb out of gas, then apply choke and crank until it's completely out of gas and won't start, let the saw cool for 8 hours at least, add fresh mixed gas and see if it's starts easily with a choke. If it won't start with a choke after several crank attempts, remove the breather and give it a small prime in the carb throat and if it goes your carb diaphragms are old and stiff. (carb will need a kit)
This will give an idea about how strong the OLD carb fuel pump diaphragms are for getting fuel to the carb.

As old2stroke says some of the EZ's want a throttle lock and a half choke even when the engine is warmed after it's rested little bit from being killed. You can feel a half choke position if you pull on the choke knob slow and easy.