Outdoor Power Equipment (Lawn Mowers, Snow Blowers, Chain Saws and more) Discussions

I have a tecumseh HS40 engine that hunts at all rpm's low or high. I have removed the carb and cleaned it, removed all needles for cleaning, checked the float for leaking(seems ok), adjusted the float level with a 11/64 drill bit, used a base setting of 1.5 turns for the high speed needle and 1 turn for the low speed. Adjusted the engine while running at high speed and low. After this it still wants to hunt at all speeds.
What should I do next. Does it need a carb kit? Do I need to adjust the governor linkage. Any help is appreciated.

Do not know what my next step should be.

I have zeroed the governor shaft to make sure it is corect and then I moved the spring from a setting 4 holes from the top to the top hole. I started the engine, let it warm up and then held the throttle in a position just past idle to see if the engine would hunt without the input from the governor and it runs steady.I wanted to do this to see if the carb was the problem but it seemed to prove it is a governor issue. I then ran the engine this time without holding the throttle linkage and the engine would still hunt a lower RPM's but is almost gone a high RPM's. Moving the spring to the upper hole has helped. While the hunting is reduced at lower RPM's it is still present.
Although I did take the carb off before I did not specifically check any passages or holes in the main jet tube as I was not aware any were present. I will check this next to make sure they are clean.

This engine has a primer button on the engine cowl and the high speed needle is on the bottom of the fuel bowl.

   On the cleaning side:  If the needle screws up into the nut it may have 1 to three holes.  One near the base will be about a 32^nd and the others much smaller – up by the end of the threads.

 

   Take off the bowl and look for the welch plug on the underside of the carb body.  It’s a circular plug with a small rectangular opening on the edge.  Spray into the opening.  A spray should come out of the left side of the outside of the upper carb body (looking into the throat).  Also spray into the tiny hole with a number of pulses. 

   Spray into the primer inlet and up into the main jet.  Blow air into the holes also if you have a compressor. 

 

   There might be residual crud left in the gas tank or line plugging things after initial cleaning but possibly you have already flushed the tank and line. 

 

   On two governor arm carbs where one governor arm went to the throttle and the other to the butterfly plate on top of the carb hunting was eliminated by lengthening the arm to plate rod.  That was done by bending a slight amount. 

Hunting is not caused by a governor problem..... It is a lean fuel mixture at the lower side of the "hunting" carb throttle setting.

The description of what is happening is below...

 1. The engine starts to lose rpms BECAUSE the carb is not delivering the right amount of fuel.

2.  The Govenor senses the loss of rpm (reacting as if load is applied) and opens the throttle to maintain desired rpm.

3.  The carb works properly at the new throttle setting and trys to overspeed past desired throttle setting.  (hense the low speed jet is plugged, or main partly plugged)

4.  The govenor trys to throttle back to the desired throttle setting, but overshoots and looses too much rpm and trys to correct....

.......   then back to action 1

Good luck

Friiy

also.... an air leak in a primer bulb or a loose carb can give a (too lean)  similar result

why cant a person copy and paste info????????????????

when the unit starts surging,   hold the throttle link from carb to goevernor arm.if the surging stops,  then the governor needs adjusting.  if surging continues when link is held it carb problems.  make sure the high and low rpms are " set" according to spec.  we usually run them at 3570 on the high end and 2000 at idle.  for adjusting the governor, as facing the carb.  set throttle lever to high speed,  butterfly will be wide open.loosen the 5/16 nut  holding the governor arm to governor shaft.  rotate shaft in the same direction the link moved,  do not move governor arm,  only the shaft clamp,   counterclockwise.

'

  maybe clockwise,  sorry im going from memory

Good News!

The engine is running like a champ. I removed the high speed needle and tube and cleaned out the two passages in the tube. I also replaced the rubber O ring on the high speed needle as it was deformed and cracked. After a quick prime and a pull the engine sang like a champ at all RPM levels. Under load the governor worked perfect.

Thanks for all your help.

Friiy  :)