# Ariens Upgrade Horsepower on 9HP



## tzoeric (Jan 5, 2020)

Hi all, quick question that has me baffled so I figure maybe some of the experts can give me some advice

I have an older 1998 Ariens model 924122 powered by an SnowKing OHSK110 11hp and also have a newer 926004 powered by a SnowKing OH318SA 9hp
They both say 318cc, and from what I can tell they are identical -and figured maybe it's the carb that is different and has bigger jets but they both come back to the same Carb part #
(See attachments of pics I took from each motor that show the same displacement)

So, instead of swapping the 11HP motor to the newer 926004, how can I bump up the power of the 9hp and make it produce 11HP? Any help would be appreciated, I'm a little baffled by the same displacement and carb, yet 2HP difference. I want more power out of that 9HP and think it can be done, but how?


Thanks!


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## nwcove (Mar 2, 2015)

What are the spec’d rpms for each engine?


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## e.fisher26 (Nov 6, 2016)

Some companies got in trouble for claiming wrong cc on some engines, 280cc is around 8hp. I have a Husqvarna with a 291cc eng which is around 9hp.


Sent from my iPhone using Tapatalk


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## Oneacer (Jan 3, 2011)

I am by no means an engine guru, or to be all knowledgeable on the output performance of an engines bore or compression specs, etc, etc...

I do, however, know the HP of an engine was somewhat flawed in many manufacturers claims. Thus, the removal of HP ratings on engines, and now the cc ratings being displayed. In my own humble opinion, even modifications, settings, etc., on identical short block displacements, power output can be manipulated.

 … all a game really for manufacturers in MHO.


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## penna stogey (Nov 25, 2019)

First post needs a Bloody Mary welcome...Greetings from Penciltucky!!


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## cranman (Jan 23, 2016)

If you want to stay with Tecumseh, find a 358 cc ....I believe the 10 flattie was the big bore...of course a 414cc or 420cc Chonda will make it spin! The hp ratings are bogus on the Tec's, like you discovered. Heck the 8 hp.is 318cc


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## 1132le (Feb 23, 2017)

The 9np and the11 hp 318cc are the same has 16.2 lb ft torq has more power then 358 flattie
its a real 10 hp those that paid for 11 got smoked those that paid for 9hp did well
its a good motor


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## cranman (Jan 23, 2016)

1132, are those OHV engines? I've got a 10 hp OHV and an 11OHV that I pulled off of Toros...identical?


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## 1132le (Feb 23, 2017)

cranman said:


> 1132, are those OHV engines? I've got a 10 hp OHV and an 11OHV that I pulled off of Toros...identical?



Yup ohv 318 cc is real 10.1 ish hp ohv 358cc is real 11.1 ish hp


Flsttie 318cc is a real 7.5 ish hp flattie 358cc is a real 9.59 ish hp


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## Kiss4aFrog (Nov 3, 2013)

:welcome: to SBF tzoeric

.


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## tzoeric (Jan 5, 2020)

I ended up buying an optical tach and increased the RPM on the 9HP - it's now at 3600 and hoping that I'll get that 11HP out of her now - just waiting for some **** snow up here in NH


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## legarem (Sep 9, 2017)

On old Tecumseh flathead motors head gaskets thickness varied so for the same displacement, one motor could have more HP with with a gasket that is less thick than another one. Look at the serial number of your motors and find the parts list. Even if they are the same motors, the head gasket could be different.


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## tzoeric (Jan 5, 2020)

Thanks, they use exactly the same gasket according to the parts breakout


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## 1132le (Feb 23, 2017)

legarem said:


> On old Tecumseh flathead motors head gaskets thickness varied so for the same displacement, one motor could have more HP with with a gasket that is less thick than another one. Look at the serial number of your motors and find the parts list. Even if they are the same motors, the head gasket could be different.



Total bs c'mon man
at best it changes comp ratio
all flattie 318cc and 358cc have same torq output per given engine no matter hp claimed 

hence the law suit and the switch to torque ratings
people saying the change it by rpms ir comp ratio are dreaming


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## legarem (Sep 9, 2017)

I wrote *COULD* have more HP not they have more HP.


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## rob_o (Dec 19, 2020)

tzoeric said:


> Hi all, quick question that has me baffled so I figure maybe some of the experts can give me some advice
> 
> I have an older 1998 Ariens model 924122 powered by an SnowKing OHSK110 11hp and also have a newer 926004 powered by a SnowKing OH318SA 9hp
> They both say 318cc, and from what I can tell they are identical -and figured maybe it's the carb that is different and has bigger jets but they both come back to the same Carb part #
> ...


There are larger carbs you can put on the engines. For example a TC- 640105 carb with a 26 mm throttle opening should boost your power. Beware that the after market carbs are not necessarily correct even if the part number you ordered is. Under that number the throttle openings of most of the carbs are not correct l not 26mm. Order OEM carbs.


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