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.

Coasteray: “it peaked out at only 3180rpm”

Coasteray: “I don't know if this meter is accurate.”

 

  It probably is.  Toro manuals spec’s give 3200 as their engine RPM.  It seemed odd so I called the factory last year and spoke with two technical reps who confirmed that.  You can check that applies to your machine by going to the Toro site and getting the manuals for your machine.

 

Adjustment:  On the 10hp Tecumseh the governor adjustment is usually a screw in back of the throttle arm.  It’s accessed through the opening for the throttle arm.

Here is a video of the screw to adjust the speed.

http://www.youtube.com/watch?v=GDe-VH4X5EA

Skip to about 2 minutes in if you want to skip the rest.

trouts2 wrote:
It is really great to hear from you, trouts2.  Do you know how to adjust RPM on Honda HS35?  It currently reads around 2600-2700rpm?  Not sure what the RPM should be as the manual states 3.5hp at 3600rpm.  Honda HS621 manual says 4.9hp at 4000 rpm but not sure if that model runs that high? Look forward to your professional wisdom.

Sounds like Toro have set the engine rpm to be at or near it's peak torque values. 

MN Runner:

Follow the carb linkage to watch what controls the engine speed.  You should be able to deduct where the governor resides and how to adjust it.  On my Toro SS with a  B&S R-tek engine, there's a metal tab where the governor spring attaches to that  can be bent toward or away from the spring depending on whether you want to increase or decrease rpm.  Find the governor spring and lightly pull/push it to see how the engine reacts.

Those old Tecumseh two strokes I have excellent governors to play with.  I have them modified to use as throttles.  Accordingly, I can raise engine speed as load demands rather than keeping at a rather anemic  constant 3600 rpm. 

MN_Runner,

Here is the illustration of the area:

MN_Runner,

   I'm not familiar with the HS35.  I was going to post the governer picture but blumonster came up with it.   I don't see anything there for adjustment, no screw to turn.

blumonster,

   Can you post what's on page 14, the governor adjust procedure?

   My guess is the adjustment is a one time setting.  You can probably tweak with the arm by setting it back or forward.  To get more rpm you could bend the rod at the top of the arm to be shorter for more rpm.

   The procedure on 14 is probably something like position the governor arm all the way clockwise and the shaft arm counter clockwise then tighten the figure 1 bolt. 

    The way they drew the bottom spring looks weird, 90 out from what it should be.

  

  

Here:

The diagrams for the Honda governor indicate that it's very much similar to the Tecumseh set up.  It can be a bit touchy to set the governor if you loosen the screw that holds the arm onto the governor shaft.  It takes very little movement to make large changes in rpm. 

blumonster,

Can you post a picture (from the service manual) on how the choke rod is connected to the carburator?  There is a small spring on top the carburator and trying to figure out how that spring is attached or used in conjunction with the choke rod.  Thanks,

MN_Runner wrote:

I hope these pages are the related pages: