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.

If you have a generator, hook the untrusted tachometer to that, and see if you get 3600 RPM.

On the flip side, if you have a generator, but no tachometer, if you have a device called a Kill-A-Watt, it will show you the frequency of your wall outlet power, to 1 decimal place. It also shows the voltage of the outlet, and the amps and watts being drawn through it. During the recent snowstorm power outages in New England, I was using my Kill-A-Watt to keep an eye on how the generator was doing under increasing loads. I could see if it was slowing down (less than 60 Hz), and what the voltage was (eg- ~125V with no load, dropped to ~118 as I loaded it up).

The tachometer seems correct as it does show 3600RPM at the full throttle on my HS928.  This old HS35 at 3600 RPM does not sound too good so I will have to watch the RPM after getting a brand new governor spring.

MN_Runner, you mean it sounds bad at 3600 rpm?If it is the factory set RPM it should not.What we got into...

It does not sound good.  Whatever I do with the current governor spring, the RPM reads 2280.  I am just wondering if something is fishy with my tachometer.

blumonster wrote:

The part that bothers me is that when it tried to go over 6" of snow, it was having some power issue.  This thing will be too weak for EOD.  I thinking about selling this 30 yr old blower and just break even.

MN_Runner wrote:
It's not the tachometer, or the spring.  The spring will affect how quickly/slowly the RPM changes, but not the governed RPM.

You have to loosen that nut on the governor arm, then slowly rotate the governor arm shaft with a needle nose plier, then tighten the nut up again.  Forgot which way to turn, but it's very touchy.  A little turn makes big changes in RPM.

You are correct.  It is just a lot of work to take the covers off to get that access on HS35 and is a real PITA.  I wish I had diagrams on how to take the covers off so I had an access to the governor.

aa335, here is the part about that nut:

MN_Runner, will just taking the rear cover be enough to reach the governor arm nut?If so it looks easier:

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. :)