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

Hi

I was wondering how or where I could look up the correct engine speed for the governer on a Tecumseh 10 hp snow blower engine.  It is an older Lawnboy ST1032 model (1980's).  I bought it second hand  a number of years ago and it has always had a tendency to rev higher than other snowblower engines that I see.  It really screams like a devil when opened out (but it is still in one piece after over 15 years with me). 

Thanks

Brian

Richie,

Thanks for the engine speeds.  I now have to borrow a tach and see if mine is in that range.  Your thoughts on torque vrs horsepower sound right for this type of application.  As I understand it, hp is necessary for acceleration, or the ability to increase speed.  Torque measures the ability of an engine to maintain a set speed given an increasing load.  That is why diesel engines (high torque - low hp) can haul heavy loads (up hill) with out losing much speed but are very slow in accelerating to a given speed.  The snowblower engines are also meant to run at a fairly constant speed regardless of the load  placed upon it.  (At least that's my understanding of it all.)

Goldrush,

I'll have to pull the shield off to see but I seem to remember the governer adjustment mechanism is just a spring-loaded phillips screw.  I think I can raise the rpm by turning it in (CW) and lower it by turning it out (CCW).  I now need a tachometer to measure the rpms.  Do you have any pics/diagrams for your method?

Thanks again, guys.

Brian

Richie wrote:

  I've even heard rumors now that the L-head engines actually produce more torque at a lower RPM than there supposedly more efficient OHV counterparts.   

Quite possibly true. Why OHV in these size engines, You know It is primarily an EPA issue. They got to justify their existance.    Don't believe anything the EPA slams down your throat.  They just want controll.  (figures don lie liar's figure) Just like the first emissino  engines .. run them at over 200 degrees, they push it by saying it is more efficient.  Not so .. the amount of waste that comes out the exhause was a lil less cause the fire was hotter.  but the engines ran more like a piece of sh@-  compared to before.  Actually with only that changed they got less milage,  so for the same amount miles you travelled you created more waste cause you had less horsepower and used more overall gas. But they didn't tell it to you that way.  How did they hide it?  the test was based at idle and maybe a slight elevated rpm, with the engine not under load.   But they did get controll,  didn't they.  Not being political here just stating a fact.  now the neighboorhood  garages go out of business cause they can't fix modern cars as the technical stuff at the engines is proprietorial.  Take a 400 plus HP street rod out on a cool night with a 160 thermostat and see if it don feel like it is 10 percent faster than  on a hot 90 degree day.

If you want to confirm your suspicion on the L-Head vs the OHV engine , on which one has more torque.  You may be able to use this general rule. (the key word being here "May" as there is a lot of different things that can be done to an engine that could make a general rule look like if is not true, but understanding the general principal is important as a starting point)The longer the stroke the more torque.  So if the engines are in the same general category  of same amount of cylinders and same approx. amount of displacement then you can use the rule. (I believe the two engines you were referring to were in this category, same amount of displacement however different length stroke etc.) Two general types of engines to oversimplfy..  Truck type engines and car engines.  Truck engines develope  their power by torque  ,  car engines develope their power by higher rev's  which actually increases horsepower.  Older automotive type references were Big block (torquer)and small block(rever.)

(Big block small block did not actually mean the size of the engine casting)  (in most cases it did go hand in hand, but sometimes it did not, like pontiac  they used the same size casting for  both big and smallblock)

Why does a longer stroke give you more torque.  Imagine a cutaway view of a single cylinder engine from the front.  When the piston is halfway down on the power stroke and you see the conn rod out at a 45 degree angle and thejournal of the crankshaft out at an opposite 45 degree angle going back to the center of the main bearings of the overall crankshaft.  Imagine it as a LEVER  .  the longer the lever the more force put back to center.  Itis  like adding a pipe to your  ratchet whenct to get more power when taking a big bolt off.  so a 3.5 inch stroke is longer than say a 3 inch so more leverage.  Does it get offset by the longer con-rod.  no it actually gives you even more, cause it creates compound action, just like you get in things like pruning shears and compound lopers etc.   Torque is best looked at as the amount of force it takes to stop a shaft.  Horse power is best looked at by how much work it will do  with a running start.  In simple truck engines  needd the torque for their heavy loads.  so do snowblowers,  More than lets say lawnmowers. 

So the industry to comply with the epa  could be substituting an OHV engine trying to do the job a little more with horsepower rather than torque.  The offset to you is you have more of a chance of stalling it out if you plow fast into a high amount of snow  the OHV with less torque will still work.  sorta of.  (also pls keep in mind here they can mix and match all kind of bores and strokes and get whatever type of horsepower figures they want, by changing the actual rpm of the test.((basing their advertized HP at an rpm they pick to suite their needs )  the only way you can sort of tell is to have the full graph of both  torque and horses  at the whole range of reasonable operating RPM. in these engines probably from 1000rpm up to say 4500 rpm.  All they care about is reducing their emissions. 

Does an L_ head produce more torque than anOHV (which is synomous with the combustion chamber being more of a hemisphericle one.Thus directing the explosion uniformally toward the center of the piston and not have to deal with the loss of the extra chamber in the L with valves being further away etc.)  the shape of the combustion chamber is not what increases the torque. It is primarily other mechanical charistics of the engine. However burning the fuel mixture a tad bit more efficiently has a tendancy to create more rpm speed and  more rpm is more conducive to create horsepower.  That is why when you look ah charts of horsepower curves and torqe curves you see almost all the torque power dives at higher rpm's  and most HP curves keep climbing.  (  just general rules here, lot of other things come into play, suvh as single cyl or multi cyl,  or   v type as opposed to in-line engines , and most important in creating revs is firing order, no need to mention that here in single cyl engine) It is all confusing a little but the epa wants controll and they will base it on exhaust emissions.  The manufacturer and the consumer will have to live with the rest.  In other words you will pay for it and they will have controll.  Why can't you find the figures or charts.  It is further proofe it is a controll issue only,  every time this happens in an industry this happens and they usually do a change in the rating formulas,  the way they did it in the auto industry is by changing the hp function  going from old fashioned Brake HP  to sae Hp  to sae net HP  YADAYAD 

What is better the L-head or the OHV.  In My own opinion.  I don't really want an OHV engine in any outdoor power equipment  under 20 horsepower.  Under 20 I prefer the L_head.  less parts, cheaper,  They both have their place.   Nothing wrong with an L-head.  OHV  engines I think are over praised in small engine outdoor power equipment  .

Hey Richie  when I was reading the other techumpseh hp thread, I noticed the discussion on the jetting issue being the only difference, and the other poster saying you can not get three hp on that size engine.  Both of you can be completely right.  Here's how when he said you cannot get that type of increase in this size motor he is 100 percent correct, assuming  you are running the motor at it's optimum horsepower in the firstplace.  And I think that was the example he was referring to .  racing engines on a dyno where they were trying to get more with jet adjustments  etc.  In that area it is hard to get more horsepower.  However if you have a certain power motor like thatand somebody did a mod to the carb you can decrease horsepower with no problem and as much as you want.  So if you start with a 400 horse engine , throw a carb on that reduces it to 200 then you have a lot of potentialto do high percentage increases in it like I opened up the jets and got 50 more HP..  so what I am saying is the Tech engineers may have been telling you the truth when you were quizzing them on a 8 and a 9 hp engine.  Why  Because it is really a potential 13 hp engine  , you are not starting with an 8 and working your way up. 

Marketing B S  AWays to get more money out of your pocket for doing nothing,  And also big time to help  the EPA  gain controll and justify their existance 

Ben07 

   Guys,

If you want a chart on the Torque and HP on a HMSK100 snow King engine.

Go to:  "Tulsa Engine warehouse", they have it on that engine.

Hope this helps!!

                                                                       Fred  

I'll take OHV everytime over an L-Head, where available. My Kohlers have all kinds of torque and are extremely effecient engines. They seldom even lug but when they do they will lug through anything I have found. I have never had a stall. The best engines I know of are Honda's GX OHV, from 2.5HP to 24HP. They are used commercially and used in anything from pumps to generators and from snowblowers to garden tractors.

Although more RPM can gain you more HP that doesn't  mean you also gain more torque. Matter of fact, if you look at the chart it would suggest that by backing off the throttle to 2600 RPM's would put your max torque at the top of your operating range and you would get more benefit in the use of your OPE if, it was all about torque. Well, we know that's not right because we know our engines and equipment perform better at top engine speeds. So, logically that would mean that more HP is advantagous in the use of our equipment. We definately benefit from more torque but to believe that torque is what it's all about, is not really correct.

Honda GX340

Hi Ben,

Marshall wrote:

I agree with the first part of your statement as that is exactly what I said.

QUOTE "That is why when you look at charts of horsepower curves and torque curves you see almost all the torque power dives at higher rpm's  and most HP curves keep climbing." 

                                                                                                                                                         

        

         

But I disagree with this part of your statement when you are using a machine such as a snowblower that can encounter a heavy load

".We definately benefit from more torque but to believe that torque is what it's all about, is not really correct."

Because if you load the machine down and you hit the point where it drops the RPM's

To a  lower range, you will need the torque to keep it running.  That's when it become a situation when it is all about torque   Look at the chart you posted  . Drop the rpm you went from 10 horsepower to 6  ,  then compare the torque curve  it isn't really much of a curve it is more of a PLATEAU.  real steady and strong from 2000 RPM  all the way up to 2800  RPM..  this is a snowblower we are talking about. ...It is accumulating and compacting weight bearing snow at the auger then has to handle the same weight load  twice when it hits the impeller and it throws it like 50 feet.  Very different requirements on this machine rather than something like a lawnmower. 

Ben07 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Because if you load the machine down and you hit the point where it drops the RPM's

To a  lower range, you will need the torque to keep it running.  That's when it become a situation when it is all about torque   Look at the chart you posted  . Drop the rpm you went from 10 horsepower to 6  ,  then compare the torque curve  it isn't really much of a curve it is more of a PLATEAU.  real steady and strong from 2000 RPM  all the way up to 2800  RPM..  this is a snowblower we are talking about. ...It is accumulating and compacting weight bearing snow at the auger then has to handle the same weight load  twice when it hits the impeller and it throws it like 50 feet.  Very different requirements on this machine rather than something like a lawnmower. 

Ben07 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Richie  that's really OK and better that your peak torque is lower than your operating rpm..  (It's better than being there at a higher rpm that you can never get at with a machine with a governor set-up.   It will be there when you need it,  when you are pushing it to the limit  and you put the machines rpm down  it will hold itself up to the task,  an don forget when you do that the governor senses the rpm drop and starts  flooring the accelerator so you are really leaning into the job.   and sometime people can't tell that the governor assist is opening the carb  till they get done with the say 20 car driveway  and their gas tank is empty.  and on lesser snows they found that they used half a tank.  That's when IT IS ALL ABOUT TORQUE.   A rev type engine will just have to slow down in that situation, yous  although under load will still  maintain throwing the snow at a much faster ground speed.    (and in that situation IIMOO that you will do the same overall job of a comparable engine that is built more as a horsepower engine that can sacrafice torque ,faster use less gas and creat significantly lower emissions)

Ben07

Ben,

That's why recently I've been concerning myself less with the horse power, rather with engine torque.  The engine is never run to achieve the rated HP anyway, and that's a fact.  At least when it comes to Briggs or Tecumseh engines, the HP/torque curve charts prove that.  I also feel you are exactly correct about fuel consumption.  Since I purchased this Toro, I've been blow snow in 1st gear, even when we only had 3" of the white stuff.  However, when New York had that recent dumping of snow, the engine used much more fuel.  It wasn't that it covered more ground, it had to remove more tons of snow.  No question about the governor doing its job. 

I should have studied harder in Physics class, I would have understood these engine grievances much easier.  Then again, if the engine specifications were more readily available, it would have answered many questions before they needed to be asked.  Thanks

Richie wrote:

Good way to summarize it all.  In OPE it is more about torque.  

Ben07