Abby’s Guide > Outdoor Power Equipment (Lawn Mowers, Snow Blowers, Chain Saws and more) > Discussions > Tecumseh 8HP tuning
Outdoor Power Equipment (Lawn Mowers, Snow Blowers, Chain Saws and more) Discussions |
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trouts2
Location: Marlboro MA
Joined: Dec 8, 2007
Points: 1328
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Re: Tecumseh 8HP tuning
Reply #1 Dec 20, 2009 11:54 am |
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>>Last year I picked up a Toro 824 Powershift blower, history unknown. When first start it, the engine hunts or surges until it gets warm then it runs fine. Is this at all normal. Some engines hunt at first until warm. I get that more with older engines. If you back off the choke too quickly they hunt but later fine out after warming up. >>I tried adjusting the jet on the bottom of the float bowl and found that when I turn it in it will eventually start to miss so I turn it back out. When I try and see where it will miss on the rich side nothing happens. I can turn it out real far with no effect. When one behaves like that where the main jet has no effect the carb usually needs cleaning. You should get sputtering going ½ to ¾ from 1 ½ out i.e either side of 1 ½ should produce an effect. If the issue is just hunting until warm and it then runs fine I would not do anything.
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mkd55
Location: wisconsin
Joined: Dec 16, 2005
Points: 155
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Re: Tecumseh 8HP tuning
Reply #3 Dec 20, 2009 1:37 pm |
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packo! use the way it starts at completely cold to fine tune the high jet adjustment.first off the high speed jet should be initially set at 1 1/2 turns out from lightly bottomed all the way in. next when you do your prestart routine,choke all the way on,primer pumped two times,throttle set at the high speed position,ignition key on,fuel line turned on.(this is my prestartup for my 8hp tecumseh)yours may be slightly different.use whatever starts your machine the easiest! once my machine starts up i can almost immediately turn the choke completely off. i can do that because the high speed jet is opened enough or rich enough for the engine to run.if you adjust the high speed in it will lean the motor out(you found that to be true!) to where it will miss and backfire and eventually quit. start at 1 1/2 turns out and start the engine,once the engine starts if you take the choke off right away use what it does as a guide to high speed adjustment. if the engine quits turn the screw out 1/4 turn and so on.use the very first cold startup as the test for high speed mixture adjustment. at completely cold startup you have the jet adjusted correctly when the engine will sustain itself when you completely take the choke off very shortly after startup. let the amount of choke you need at cold start to keep the engine running be your guide.too lean and the engine will not stay running without the choke at all,too rich and the engine will not pull under extreme loads and will show signs of black soot out the exhaust. you want the jet adjusted so within 5 seconds of cold start the engine will stay running with no choke at all. find that needle setting ( don't ad any more!! ) and you'll be good to go.keep in mind the above is not optimum and is a little rich but you will like the way it starts,stays running,and overall performs as adjusted above. if you need anymore help mkdahl@charter.net i'll be glad to help you.
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qlty
Joined: Dec 8, 2007
Points: 7
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Re: Tecumseh 8HP tuning
Reply #5 Dec 26, 2009 10:27 am |
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Hunting = engine is running lean.If only till warm up it could be a vacume leak.check the bolts holding the carborator to the engine.To find a leak you could use a small propane tourch (not lit) appling a small amount of gas to various areas,if engine picks up speed or smoothes out you have found the leak.
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