Tecumseh 6hp engine surging

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Old 11-11-19, 12:57 PM
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Tecumseh 6hp engine surging

Hi folks,
I just purchased a Cyclone Rake (tow-behind leaf vacuum) that uses a 6 hp Tecumseh engine. Attached is a picture of the engine plate. I have a few questions about this motor as I am trying to get it running at maximum performance for the enormous amount of oak leaves out back! I changed the oil, air filter, spark plug and I emptied, as best I could, the fuel tank because the seller said he put "stable" in it. Unfortunately the engine is still surging, or rev'ing up and down.
1. Any obvious culprits to look for?
2. Could a small amount of left over stable be the cause?
3. Tecumseh went out of business in 2008, does anyone know if you can still get parts (or advice) for this engine?
4. On the engine plate is an attribute: "D.O.M. 0299" Is this the actual date it was manufactured? Feb 1999?
Thanks for any help!
 
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11-11-19, 07:32 PM
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The carb needs cleaning. There may be a small brass jet screwed into the side of the carb. It may have a plastic cap over it that needs to be plucked out. Depends on which carb it has. There is a tiny hole in the end of that jet and it takes a very fine wire to clear it out. That's usually the problem area on these. There are also holes in the sides of the bowl nut. One is tiny and in a small unthreaded section. It is also commonly the cause of this problem.
 
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Old 11-11-19, 02:08 PM
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Id be looking into the function of the governor!
 
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Old 11-11-19, 02:08 PM
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The first thing I would check for surging is that the gasket is in good shape and the carburetor is secure to the engine. To check for leaks there you can lightly spray the gasket area with carburetor cleaner or WD40 to see if it gets sucked in.
 
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Old 11-11-19, 07:32 PM
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The carb needs cleaning. There may be a small brass jet screwed into the side of the carb. It may have a plastic cap over it that needs to be plucked out. Depends on which carb it has. There is a tiny hole in the end of that jet and it takes a very fine wire to clear it out. That's usually the problem area on these. There are also holes in the sides of the bowl nut. One is tiny and in a small unthreaded section. It is also commonly the cause of this problem.
 
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Old 11-12-19, 08:49 AM
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Old 11-12-19, 09:31 AM
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Hey Joe, Thanks for the link. Learned something today and now I know where to get those small wire cleaning tools.
 
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Old 11-13-19, 12:22 PM
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This video did not cover Tecumseh carbs, or did it?
 
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Old 11-13-19, 12:27 PM
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As of late I've had good success with cleaning carburetors using an air compressor.
 
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Old 11-13-19, 02:24 PM
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Here is a link for Tecumseh carbs. Have a good one. Geo

Tecumseh Carburetor Diagram,Tecumseh Carb Diagram | Tecumseh Carburetor Guide
 
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Old 11-14-19, 12:31 PM
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Thank you very much Geo!!! I was searching the web last night for just such a diagram and/or article and didn't find anything that good!
 
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Old 11-14-19, 01:08 PM
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Thank you to everyone that contributed to this thread! I sprayed a bunch of engine de-greaser (petroleum distillates) to the sides of the carb and scrubbed it with a toothbrush. I thought I was chasing a vacuum leak based on the video with the beer-chugging-Honda-guy, but it may have been just mucked-up with grime. I had a hell of time getting it started, but when it did fire up the surging dampened out to nothing. I still have a couple of questions:
1. Pushing the throttle lever all the way up (rabbit) (vs. all the way down (turtle)), it clicks at the last moment. With the air cleaner off, I saw a (butterfly?) flap slap shut. I assume this choke-mode (sorry, sort of new to this). The engine runs at high RPM and continues to do so. Usually my two-cycle weed-wacker gets bogged down after a couple of moments in choke-mode and I have to click it off. How is it that this engine can run in choke mode?
2. When I inspect all of the linkages associated with this carb, and I move the throttle lever up (or down), the only thing I see ever moving is when it clicks into choke-mode, at which point I see a quarter-circle armature(?) click 90-degrees to another position. So why can't I see what is causing the engine to rev-up or down based on the throttle-lever?

I'd like to learn how this carb works and its various adjustments, so any helpful 101-level links would be appreciated but not necessary at this time. Again, thanks to all for your help.
 

Last edited by umby63; 11-14-19 at 03:14 PM. Reason: New discovery, no need for attached pic
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Old 11-14-19, 01:16 PM
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I had a surging problem big time with my latest Barn Find Tecumseh 7 hp Vertical shaft. I finally got to the point where the only thing I hadn't done was to hit the idle mixture screw jet opening with a serious blast of compressed air. After i did that I was able to tune out the surge and it runs as good as new (1987 serial number lol)
 
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