Posted on 06/30/2011 1:25:59 PM PDT by djf
OK I have and older small Homelite chain saw.
What can make it act up (not run, doesn't want to start) when it's hot?
I've checked everything - carb, spark, the chain is free and well oiled...
Very perplexing because it's so stubborn. Let it set for 15 minutes and it starts up like gangbusters!
I've taken apart and rebuilt several small engines on various mowers/tillers/etc and this one has me stumped!
Flooded.......ck the hose to the tank and its return. The one way valve or its gasket is leaking......
Did you change the spark plug? I had a riding lawn mower that would run fine for about 45 minutes then it would miss a few times and quit. A new plug fixed the problem.
Try replacing the magneto. I’m on my third magneto for my Lawnboy 2 cycle mower. Starts and runs fine, but shut it down when hot, and you can’t get it restarted until it cools down.
A new magneto coil fixes it for about 3 seasons, then the hot starting problem returns.
Just a suggestion- check the choke springs. Sounds like a problem one of my colleagues was having with his, and that was how he solved his.
I second the leaky gasket.
Check fastener tightness at the least. Visually inspect gaskets if possible.
Do you have another saw or tool implement that takes the same type spark plug? Borrow one? Sometimes the plug looks fine, clean, properly gapped, etc. yet the porcelain can be cracked and when hot, will fail. Try a substitute and see if difference noted.
Only three things for engines... Fire, Fuel, and Air.
Sometimes the ignition coils on some small engines give you trouble when they get too hot - then you won’t get the spark. Maybe you can get someone to check the coil for you. Sometimes small shops will do that. (Autozone often checks engine parts for cars, for instance, but I bet they wouldn’t do that for a chainsaw...)
Two things have never worked for me. Chainsaws and gas powered weed eaters. Even brand new ones. I how have a battery powered weed eater and tiller.
Tips on chainsaws:
1. Everytime it starts to run badly, or fails to start on the second pull, change the aircleaner and the plug. it should start and keep running fine. My Stihl was maintained like that for nearly fifteen years before I gave it away. the other tip is that every time you refill the gasoline tank, sharpen the chain with an electric sharpener or manually with a file. Chainsaw was never in the shop and had hundreds of hours on it.
2. The above works with lawnmowers too. Sharpen the blade with an attachment for your electric drill because it will allow the engine to run at lower speeds and preserves that engine. Had a mower that lasted 18 years and always started on the second pull.
Sounds like vapor lock. Fuel gets hot in the tank, produces a vapor that gets in the gas line and doesn’t allow fuel to flow to the engine. Remove the fuel line on the engine side, get fuel flowing through the line and reconnect.
Can happen a lot on hot days when the tank from the outside air temp or sunlight heating heats up the gas in the tank.
Years ago I was instructed by a wise man that, if I ever got a Homelite machine started, I was never to shut it off but should simply keep it fueled for as long as I could. Homelites only start once, maybe twice.
That is what I was told.
For very small 2-cycle engines, I like to use canned, pre-mixed gasoline. Menards carries it. It is ethanol free.
Hold the spark plug wire and give the cord a yank. You’ll find out if the magneto works or not. Or get your wife to hold it. If you think she can take a joke.
They make electric chainsaws, too. I have both types.....
Thanks for all the tips. Alot of good things to check out.
Unfortunately, the coil seems to be no longer available, so hopefully, it’s something else!
It doesn’t always do it... and when it’s running, it’s a dang nice little saw!
Use the WD-40 test:
Spray WD-40 into the carb then try to start.
If it does start and run a little then you have a fuel problem. The engine is burning the WD-40 and is not running because it isn’t getting any fuel.
If it doesn’t start and run a little then, you have an electrical problem, try the plug first and work back from that.
Your facts reminded me of a long-ago, natural-gas burning clothes dryer problem. The dryer would start and run perfectly for a while, before quitting.
The problem was electrical. A small electrical coil that controlled gas flow opened (continuity inside coil disappeared) when the temperature went up. Then, upon cooling, that coil was again operable.
Good luck with it.
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