carbtuning

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Topic :Carburetor tuning You're just the resource I was hoping to find on the web! I have an Ariens snowblower with a Tecumseh 4hp engine. It's been around for quite some time, and last year refused to start. The plug is clean and adjusted - squirting starter fluid into the cylinder would let it kick over, but it wouldn't keep running for more than a second. I figured it was the carb (the past few years, I'd always need to take the bowl off and clean the needle. It always used to start after that.) Recently, I removed and cleaned the carburetor - squirting cleaner fluid in every hole I could find and making sure the fluid shot out another hole somewhere. Now it will start when the choke is full on. If I move the choke back it runs okay for a few seconds, then starts to speed up and slow down by itself, until it finally stops. I noticed that the throttle is wide open when it finally stops. Is it getting too much air? How do I go about getting a small engine running smoothly? What needs to be checked and in what order? Lastly, is there a particular resource book a small engine you would recommend above others?
It's tough to say exactly what the problem is, but I would start on the adjustment screws and go from there. It sounds like you have it fairly clean, so start with the screws. Simply turn the adjustment screw(s) all the way in finger tight, then turn them out 1 1/2 turns and try to start the motor. It should run, but it may run rough. If you can get it to stay running, turn the screws little by little until the motor smooths out. You may need to experiment a bit to get the sweet setting. If that doesn't seem to help, then it could be a bad head gasket, carb gasket, or even a corroded jet. Snowblower motors are prone to gasket problems due to the cold snow hitting the hot motor. Try the screws and let me know where that leaves you. We'll take it from there. Here's the book you requested. I have one on my site listed that I love. Go to http://www.household-helper.com/amazon and go to the last book on the page. It's about lawnmowers, but the motors are basically the same. I also use the Techumsa technical manual for 3hp-10hp motors quite a bit. You should be able to pick that up at a mower shop for about $10