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.

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?

I sold my HS35 this afternoon.  The governor works and it does maintain the RPM (just not at 4000 like the service manual says) under the load and blows the snow reasonably well.  I just did not want to sink more money and time into this machine than I am willing to invest on a 30 year old machine as the parts are sometime obsolete and not available.  I would have kept the blower if it were upgradeable to GX160 but  the HS35 platform cannot take GX160 as G150 has a lower height.

Your HP formula has a fault, does the term "Torque curve" or "Power curve" ring any bells? You will have a maximum torque at a given speed, after you reach that speed the torque falls off. Were it not for the curve, you should be able to the the motor together until around 5000 RPM, that should put you in the 15 HP range.

blumonster wrote:
blumonster -  Normally on a set up such as this.  You would increase the tension of the gov. spring to increase the RPM.  All of the old Toro 2 cycle blowers had set ups like this  The gov spring was either attached to a metal tab that you would bend to increase the spring tension.  Or it was connected to a small bracket that you would loosen and slid to increase the spring tension.  The set up on the Honda HS35 is the same way.  You move the spring to another hole in the bracket which is further away from the gov. arm which increases the spring tension, which will increase the RPM.  Having said that, if the gov spring is very old there is a good chance that it has lost some of it's spring tension.  So moving it to another hole may or may not do what it should do.  In that case a person can buy a new spring or shorten the loop on one end of the old spring.  Shortening the spring a little will increase the tension to offset what has been lost over the years.
As I posted before.  Loosening the gov. arm on the gov. shaft should really not ever have to be done unless the bolt has some how come loose.  Doing that procedure simple resets the gov. to it's original setting.  It won't help or change anything
if you have a bad gov spring.  The gov works against the gov spring.  To weak a gov spring lower RPM  to strong a gov. spring and you will over rev the engine.

On my Tecumseh two cycle engines, I've tied a piece of string to the governor lever arm and run it outside the plastic housing up the handle and rigged it to work like a throttle.  I let the machines idle down when not under load then put tension on the string to pull the arm to over-ride the governor.  I get some pretty good engine speed and power doing this.   The engine is rated at 5 h.p. at 3600 rpm, which I find a bit of a stretch.  However, crank it up to 6000 or 6500 and it makes some serious power.  Enough to impress me with how much and far it pump snow.   I use the old SS machines like a I use a chain saw.  No load, no rpm.  Heavy load, high rpm.  It's actually quite controllable.

borat wrote:
Wow, 6500 RPM?? The engines hold up OK at that speed? Granted, you're only doing that occasionally. The extra RPM would give you a great boost in impeller/paddle tip speed, which must be a big help. At least with a 2-stroke you shouldn't have to worry about valve float and things like that.