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Discussion Starter #1 (Edited)
Its a 8 hp Tecumseh. I have cleaned the carburetor
When I start cold with full choke, then slowly rev it up while pushing in the choke white smoke comes out exhaust and it sputters for less than 1/2 min just before I fully rev it up. As soon as it runs at full speed for a another 1/2 minute or so it clears and is fine. When warm, engine runs fine and if I restart while its warm,-no white smoke. I usually start it set at about 1/2 throttle or a little less. My question is what causes the white smoke and sputtering at the end while starting.
Thanks for a response.
 

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Discussion Starter #4
How much throttle do you have applied when you start it?
A little less than half throttle to start.

I put it at full choke, prime it a couple of times . As soon as it starts I slowly push the choke in and it revs up ok up until suddenly white smoke comes out the exhaust. Then I give some more throttle and this seems to keep it going and clears out the white smoke until it warms/revs more and runs fine.
I haven't a compression tester, but have found an older good quality one in the classified that I plan to pick up by the end of the week.
 

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A little less than half throttle to start.

I put it at full choke, prime it a couple of times . As soon as it starts I slowly push the choke in and it revs up ok up until suddenly white smoke comes out the exhaust. Then I give some more throttle and this seems to keep it going and clears out the white smoke until it warms/revs more and runs fine.
I haven't a compression tester, but have found an older good quality one in the classified that I plan to pick up by the end of the week.
running rough? water in gas?
An engine will run with water in the gas....back in the 70s (remember the gas crunch?) I had a science teacher that built a water injector for one of his cars to increase the mpg, us kids all thought he was crazy until he brought his Delta88 w/rocket350 to school....don't remember the exactly the numbers but it was something like 18mpg jumped to 25mpg, also I believe it increased the compression.

white smoke - moisture/water, black smoke - gas, blue smoke - oil

.....in my limited experience anyway, as I only tinker
 

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I use full throttle to start when cold or hot. All the manufacturers that I am aware of say to use full throttle when starting. As said before, white smoke may be water burning off from ethanol fuel absorbing too much water out of the air or condensation in the engine/exhaust being burned off.

What is the point of using half throttle? Thin oil and a fast engine will distribute oil quickly to the moving parts.

Good luck.
 

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Discussion Starter #9
I use full throttle to start when cold or hot. All the manufacturers that I am aware of say to use full throttle when starting. As said before, white smoke may be water burning off from ethanol fuel absorbing too much water out of the air or condensation in the engine/exhaust being burned off.

What is the point of using half throttle? Thin oil and a fast engine will distribute oil quickly to the moving parts.

Good luck.
My motor does not start up fast and the oil is thick. I keep it outside in a non-heated shed. I've always thought in cold conditions its better to let any engine warm up slowly. I know its important as far as engine longevity goes to get oil distribution ASP and in cars block heaters help with this problem. Thanks for your input
 

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Discussion Starter #10 (Edited)
I checked the compression and it is 60 , which I understand is normal for this engine as it has a decompression feature to help with starting?
The plug is new/gapped . I started it yesterday and barely a trace of white smoke and it throttled up okay. In warm weather there was no smoke.
I use ethanol free with star-tron
Maybe it is condensation. (White smoke)
This is only the 3rd time I've started it this winter and we have been having week long intervals of warm/cold weather temperatures that are fairly extreme.
 

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I checked the compression and it is 60 , which I understand is normal for this engine as it has a decompression feature to help with starting?
The plug is new/gapped . I started it yesterday and barely a trace of white smoke and it throttled up okay. In warm weather there was no smoke.
I use ethanol free with star-tron
Maybe it is condensation. (White smoke)
This is only the 3rd time I've started it this winter and we have been having week long intervals of warm/cold weather temperatures that are fairly extreme.
Check if the crankcase breather tube is blocked.
 

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Discussion Starter #13
Sometimes white smoke is confused with blue/white smoke...which will be oil burning...Is it possible your carb is leaking into the crankcase...diluting the oil..?
I filled the oil to the full level. I've run the machine about 3 hrs (bit more than a gallon of gas) this season and no noticeable change on the dipstick. It only smoked when I started it.
 

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Discussion Starter #16
Check if the crankcase breather tube is blocked.
I held my finger over the end of the tube when running and it built up back pressure. I must admit the smoke may be bluish white. I'll keep a close watch on the oil level and hopefully run it as is until spring - then take it apart. I bought it used last fall did some work on the tractor part but only cleaned the carburetor... not sure it could handle 30" of snow tho'
 
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