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Discussion Starter #1
I just came into a 5 hp Tecumseh blower. I went through the carbs and did some general maintenance and got her started up. When I went to start it up this morning I couldn't get it to fire up. Pulled the plug and it was dry. After priming, pulling, priming, pulling, etc the carb was overflowing with gas, but still a dry plug. I ended up pulling the plug and throwing some gas directly into the cylinder and it fired right up and ran like a top. I turned it off and tried pull starting it and it fired right up.

Any ideas? Seems strange to me.

Thanks in advance!
 

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Unit is tilted so gas in carb can't run into the combustion chamber? Does one wheel have less air than the other? A spider built a cocoon at the bottom of the carb, essentially making a dam that the fuel can't flow over? Dunno. Just swingin' wild here. LOL
 

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.

I had an old 440 jet ski that acted like this.

The carbs were fine

It had low compression due to stuck rings.

Low compression also results in low suction (to pull in fuel)

Check compression

And also for air leaks in between carb and cylnder head
.
 

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I just came into a 5 hp Tecumseh blower. I went through the carbs and did some general maintenance and got her started up. When I went to start it up this morning I couldn't get it to fire up. Pulled the plug and it was dry. After priming, pulling, priming, pulling, etc the carb was overflowing with gas, but still a dry plug. I ended up pulling the plug and throwing some gas directly into the cylinder and it fired right up and ran like a top. I turned it off and tried pull starting it and it fired right up.

Any ideas? Seems strange to me.

Thanks in advance!
How did the choke work ... you only mentioned priming.
 

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I'm thinking air leak too. Carb to intake elbow or elbow to block. Had the same problem with a 10hp snapper. Found it was just loose bolts keeping it from starting.

.
 

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Discussion Starter #9
Copression feels solid, it's not boggy when pulled and has good resistance. There doesn't appear to be any blow-by around the head gasket either. Also when it runs it runs strong and has no trouble tackling heavy snow/loads. It's at my gf's place, who I fixed it for (so I would have to shovel her nightmare driveway anymore), so I can't do a compression check at the moment. Next time I go over. It's not an old blower, from what she said the thing probably has under 25 hours on it. I will also check the elbow to block bolts when I get a chance.

The choke is functional but seems to have no effect on delivering fuel to the cylinder.

The carb and intake were clean when removed, so I doubt it's an obstruction. Considering that it runs well and restarts once ran I would rule that out.

Maybe it was just a fluke and it will start right up next time, we'll see next snow storm.

Thanks, guys.
 

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The choke is functional but seems to have no effect on delivering fuel to the cylinder.
what do u mean. if moving the choke from on to off and vice a versa does not change engine sound or rpms then thats wrong.
choke only controls the amount of air entering carb. on means less air(air is choked=less), off means more air for normal operating condition when warmed up from a cold start.
 

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If the choke plate ended up missing somehow, that would definitely cause what you are seeing. Might want to take a peek into the carb intake and check . . . .
 

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Discussion Starter #12
what do u mean. if moving the choke from on to off and vice a versa does not change engine sound or rpms then thats wrong.
choke only controls the amount of air entering carb. on means less air(air is choked=less), off means more air for normal operating condition when warmed up from a cold start.
I just meant that the plug was dry with the choke in both open and closed postitions; neither made a difference in fuel delivery. I will check for vac leak next time I get my hands on it, spray some start fluid around the jug flange once I get it running and see what happens.
 

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start it with starting fluid, once running close the choke rpm should drop , exhaust might smoke, This means choke is working, If no change check your choke linkage
 

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What about your primer, does it feel like it is pumping gas into the carb? My machine will not start without 3 primer pumps, then it is first pull. If I forget to prime but on full choke the engine feels dead no matter how many pulls of the starter.
 

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Discussion Starter #16
What about your primer, does it feel like it is pumping gas into the carb? My machine will not start without 3 primer pumps, then it is first pull. If I forget to prime but on full choke the engine feels dead no matter how many pulls of the starter.
I believe the primer works by pressurizing the bowl and forcing gas up through the main jet into the venturi. The bulb pumps air (as I think it should, if my assessment is correct), and if I pump it enough gas will spill from the carb intake, so I think it's working fine.
 

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I believe the primer works by pressurizing the bowl and forcing gas up through the main jet into the venturi. The bulb pumps air (as I think it should, if my assessment is correct), and if I pump it enough gas will spill from the carb intake, so I think it's working fine.
You are correct. The bulb and line stay dry, and the gentle air pressure it puts into the float bowl forces fuel through the carb passages and into the carb throat. Fuel vapor and such will still be present to cause the line to degrade over time, but you won't feel the same resistance in the primer bulb as if there were liquid in it.
 

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Discussion Starter #19
I went back for round three and she fired right up second pull, evidently it just needed to be ran a bit.
Thanks for your help, all!
 
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