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

At least Briggs has all this in writing on their website it you know enough to look for it.  Obviously Tecumseh and any other engine manufacturer follows this same rating procedure.  Pretty lousy numbers when you think about gross HP as opposed to BHP that we are really concerned with.  Still, they don't mention if this rating system takes into account the very lean EPA carburetors, so I'd have to say no, which means its even worse.  If you look at the last paragraph that I highlighted in RED, this supposedly 8 hp engine I have that is run in ACTUAL conditions and NOT in optimum laboratory conditions, has a pitiful rating, as do all of our engines.

Horsepower Ratings

The power ratings shown with the individual engine series on the preceding pages are established in accordance with SAE (Society of Automotive Engineers) code J1940 (Small Engine Power & Torque Rating Procedure) (Proposed Revision 2001-09). Power curve and engine performance data are obtained in accordance with SAE J1349 (Net) or J1995 (Gross) Engine Power Test Codes.

In accordance with SAE J1349 (Net) or J1995 (Gross) Engine Power Test Codes, power curves are developed from laboratory test engines and are corrected to standard conditions which are:

Altitude: 100 meters (328 ft)

Ambient Temperature: 77 F (25 C)

If the engine will be operated under ambient conditions different from above standard conditions, the following factors should be accounted for in estimating "on site" power output:

Engine power will decrease 3.5% for each 1000 ft (300 m) above sea level and 1% for each 10 F (5.6 C) above standard temperature of 60 F (15.6 C).

The actual "on site" power output will also vary depending on other factors including the manner in which the engine is operated, the fuel that is used, and the application in which it is installed.

The "Maximum BHP" curve represents maximum performance output of optimum laboratory test engines of a particular model. A statistical mean of production engines, with 95% confidence, will develop no less than 85% of the Maximum BHP when tested after run-in to reduce friction and after clean-out of combustion chamber, with valves, carburetor and ignition systems adjusted to laboratory standards.

The "Recommended Maximum Operating BHP" is a calculated curve and represents 85% of the maximum BHP curve. For practical operation, BHP load and speed should be within the limits shown in the "Recommended Maximum Operating BHP" curve.

If the maximum speed of the engine specified for a given application is governed to a speed less than the speed at which the Maximum BHP occurs, the engine will not achieve the Maximum BHP in that application. For applications requiring operation at other than the recommended engine speeds, complete details of the proposed engine installation should be referred to the factory for evaluation.

Source:  Briggs & Stratton Technical/Warranty
http://www.commercialpower.com/display/router.asp?DOCID=76491

MissSnowshoveler wrote:

Hey Sherri,

That's good to know, thanks.  Hey, I love working on the old stuff, I'll get that Saw and Generator working in no time.

BTW...I'm actually buried under all that stuff.  The other day, while kneeling down trying to clean the place up, someone rolled a big heavy snowblower over my back and pinned me there.  I wish someone would come and help me, the tire chains are still digging into the back of my head

Richie wrote:
All the more reason for " OVER-POWERED IS USUALLY ADEQUATE"

Richie...

the lawnmower is a bit of a different story,your gonna love this.

the engine is capable of its 6.5 horsepower.however the blade is the limiting factor.

there is a certain rpm allowed for the length of blade installed on the mower.

basically it amounts to how many feet per minute the tips of the blade travels.

so in a sense you are CORRECT the numbers are crappy.

they take a high horse motor and slap it on a mower and then wind the throttle speed so far down that it can barley get out of its own way.

remember when we had those little 3.5 or even 2.75 horse 19 inch cut mowers.they would turn up like a racecar and would mow down anything you could push it through.

its all about the blade tip speed  and that even changed,i think it was 21000 feet per minute and now its 19000 .not positive on the actual number but you get the idea.

longer blade ,slower its allowed to go ...or it will break up and thats not pretty especially if you wear sandals.

ps i hope you get your butt out from that pile of junk...i have a bunch of work to get done .

later chris

MountainMan wrote:

Mountain,

I have to agree with you on that one  The problem is that over-powered or purchasing more engine than you may need is really expensive.  I suppose the way things are, it's a no win situation for the consumer.

snowshoveler wrote:

Chris,

.     

"I suppose the way things are, it's a no win situation for the consumer."

Well, that might be taking it a tad too far. LOL 

When you get down to the nut cutting, if you bought an engine that will throw your snow how you imagined it to be thrown with the HP you thought you bought, regardless of what the sticker says on the cowling, you're winning.




But, I know what you're saying.

Richie wrote:

Not much different than getting the upgraded larger motor in a truck.  I couldove bought the 9 HP 24", but went to a 1128. Noty like i was doubling the price.

On my 48" mower, price diff between a single cylinder and the Kawasaki twin was negligible, a worthwhile investment. The 15 HP is there when you need it, and if I ever selll it, will hold its value.

MountainMan wrote:

Mountain,

MountainMan wrote:
All the more reason for " OVER-POWERED IS USUALLY ADEQUATE"

Hey Mountain,

I think this qualifies in that area  Here is a really great way to make any OPE engine come to life.  It just goes to show you that no matter what size engine you have, you can always find a company that produces high performance products for it.  Too bad a snowblower would be difficult to modify for this type of thing.  Sure looks real cool and it could make a Briggs 5 HP or larger OPE engine scream

 http://www.hscsupercharger.com/

That would make a Go Cart a screamer!