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

I just started using my new hour meter/tachometer today on my blower, and it peaked out at only 3180rpm, but steadily displayed 3120rpm.  It is this one:

http://www.amazon.com/Tachometer-Kawasaki-Motorcycle-Generator-Snowmobile/dp/B0049IFX56/ref=sr_1_cc_1?s=electronics&ie=UTF8&qid=1321768364&sr=1-1-catcorr 
         

Using that horsepower-to-torque formula (HP = torque x rpm, divided by 5252), I get 8.66 HP at 3120rpm.  At 3600, it would be 9.993 HP.  For the formula I used a torque figure of 14.58, which I got by plugging in the assumed Tecumseh 10.0 HP figure at the assumed rpm of 3600, into the torque-to-horsepower formula (HP x 5252, divided by 3600).  Lots of assumptions, I know, but I had to get the torque figure that way so I could turn around the formula to get my horsepower figure at 3120rpm.

Anyway, I don't know if this meter is accurate.  When my son and I get his Ariens ST824 put back together again (took it apart to paint the inside of the housing; adjust the chains; replace the friction disc, cracked handlebars, and beat-up/bent impeller; serrate the augers using a Platinum 30 cardboard template I made while at Home Depot; greasing the chains, auger shaft, and friction disc shaft), then I will try my tachometer on his machine.  I may just pick up another meter to compare in the end. 

If the reading is the same on his, or close, then maybe it is the meter.  If he gets around 3600rpm at full throttle, then maybe I need to adjust my governor.   If I do have to adjust it, does anyone know how to do that?  It's only a three-year old Tecumseh L-Head 358cc.  Thanks for any help.

RPM increases if I manually move the governor but does not seem to stay at a higher RPM if I just make the spring tighter.  No matter what I do, the RPM ready 2300.

 

Aa355: “The spring will affect how quickly/slowly the RPM changes, but not the governed RPM.”

 

   According to the service manual it does.

 

MN_Runner:

 

   You can try the spring positions which should make an RPM difference.  That is provided the spring has not flabbed out.  If it’s not making a difference then you could get a new spring but before that I’d do what Borat, aa355 and I have suggested which

Is tweak the governor position on it’s shaft for more REV’s.

 

   On your tach.  If it was reading a steady value before and after you moved the governor arm and heard the motor rev higher then it may have been due to a few things.  When you moved it you did not hold it steady for long enough for the tach to sample.  There response is pretty slow.  If you held the arm for several seconds and the tach still did not show an increase then it could be your sensing wire is not wound enough turns or some other setup thing causing a bogus reading.  It could also be a bum tach. 

   Many have a setting for two and four stroke engines.  When set wrong they will sometimes output correct values and sometimes not.  When set right – good values.   

A small suggestion for what it's worth.  On some of the small and older Tecumseh engines.  The way that made adjustments to the Gov rod to increase RPM was to.  Bend the Gov rod a small amount.
(That would be the small diameter rod with the spring on it.  That runs from the Gov arm to the throttle on the carb).  If you put a slight bow in it, it shortens it.  That was the way it was done.
 It's very easy to make very small adjustments .... RPM up or back down.   It's a whole lot easier than messing with the Gov arm attachment bolt.

The adjustments given above for the Gov. are really to set the full open throttle position.  In relation to the Gov itself. 
Making small adjustments can be difficult.  And because there is no throttle control.  As soon as you start the engine it goes to full throttle.  So if you do mess with that adjustment. Be ready to shut it down in case
you went to far.  Or low RPMs won't be your problem.  You'll have larger ones.  If you know what I mean. :)

I will try your ideas first on Wed then I am planning to drill 1 inch hole so I have an easy access to the governor arm shaft.  Once I resolve this RPM issue, the blower will be very good.

blumonster wrote:

It is much easier from the backdoor (rear cover) approach.  I have a full access to the governor and the spring so it will be easier for me to adjust now. Thanks for the diagram.  I will let you know how this goes once I figure out how to increase the RPM.

I purchased one of those tach/hour meters for my Husqvarna snow blower.   It  cost $42.95 US.    The engine is a Briggs, 305, 1450 torque engine.     At full throttle it reads exactly 3600 rpm, 

I tried per aa335, but the governor shaft does not move at all.  It does blow snow ok so it really is not worth adjusting it since it does not sound all that good at higher RPM anyway.

if the governor shaft will not move then you have a problem with the governor.  in order for the governor to control the engine speed it must be able to open and close the throttle plate on the carburator.

MN_Runner wrote:
Since you were able to change engine speed by moving the governor arm, I suspect that the governor shaft is stuck to the governor arm.  You can try spraying a small amount of penetrating fluid at the joint and break it loose.

aa335: "Since you were able to change engine speed by moving the governor arm, I suspect that the governor shaft is stuck to the governor arm.  You can try spraying a small amount of penetrating fluid at the joint and break it loose."

  No.  He has moved the governor arm which should be bound (bolted) to shaft by the 6 x 20 bolt and nut.  The shaft should be turning when the arm is moved.  He says the shaft can't be turned so the arm is not bound to the shaft as it should be.  The bolt is probably loose or the shaft worn. 

  Carlb is right.  That shaft has to move.

NM_Runner:  "It does blow snow ok so it really is not worth adjusting it since it does not sound all that good at higher RPM anyway."

   If it's over rev'ing it won't sound good but worth adjusting.   The governor keeps the engine from over'reving.  It also keeps the rev's constant for any throttle setting.  At full throttle the engine will sag under load.  The governor will sense that and move to increase the carb throttle to get more gas and keep the rev's constant for the load.  Without a working governor an engine will sag when loaded and be pretty useless.

So how do we adjust it? How should MN_Runner proceed?