# 11 hp from 10 hp



## Abcsnow (Dec 19, 2018)

I have a 828 LXE and last year I replaced the motor with a 10 hp tecumseh. I found it had more strength.This year I have access to an 11 hp and would like t know if this would be an easy bolt on.Strange when I look at both motor tags and see they are both 358cc.wondering what the stroke bore differences might be and wether I will actually have more power.


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## RedOctobyr (Mar 2, 2014)

Is the 10hp a flathead, and the 11hp an OHV? If not, and they are fundamentally the same engine, it's possible that the main difference is in the sticker  Companies have played somewhat fast and loose with their power claims.


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## paulm12 (May 22, 2015)

yeah, as Red pointed out, these HP ratings are not always accurate. It could be that the 11hp engine, if the same technologies (OHV, etc) has better valves, etc, or maybe they rev the engine a bit more. But if the same bore and stroke, they most likely have the same overall and mounting dimensions. They could have a different crankshaft though, so check that out before you install it.


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## Abcsnow (Dec 19, 2018)

I know when I went from the 8 to the 10 the tag showed more CC’s, funny not so with the 11hp.


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## Abcsnow (Dec 19, 2018)

How would I know if the stroke were different.


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## RedOctobyr (Mar 2, 2014)

I had a 318cc flathead Tecumseh, they called it 8hp. I have a 318cc OHV Tecumseh, they call it 10hp. 

As I understand it, OHV engines have a more efficient head design, and presumably a higher compression ratio. The valves are directly over the piston, not adding "wasted" volume by positioning them off to the side, like a flathead. 

So I could see the 11hp engine maybe being better if it's a 358cc flathead 10hp, vs 358cc OHV 11hp. 

But if they're both flatheads or OHV, I'm not sure I'd go to a lot of trouble to swap them. You might get more benefit by making sure yours is running at the proper RPM, rather than accidentally a little slow by a few hundred RPM, due to a carb that's not quite adjusted perfectly, etc.


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## paulm12 (May 22, 2015)

ABC: can you provide the engine part numbers? usually stamped on the top of the main shroud (under elec start if there) and also on a sticker on the shroud.


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## RedOctobyr (Mar 2, 2014)

Abcsnow said:


> How would I know if the stroke were different.


You can measure the stroke. You can stick something down through the spark plug hole, like a long piece of wire, etc, then measure its travel through the piston's range of travel. 

But if they're the same displacement, I'd be surprised if their bores and strokes didn't match. Changing bore or stroke requires making different pistons, or crankshafts. That's a lot of expense for the manufacturer, to end up producing the same displacement. If they were going to make a different set of parts, I'd expect them to use that to also change the displacement. 

You can likely look up specs (RPM, bore, stroke, etc) based on the full engine part numbers.


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## 1132le (Feb 23, 2017)

paulm12 said:


> yeah, as Red pointed out, these HP ratings are not always accurate. It could be that the 11hp engine, if the same technologies (OHV, etc) has better valves, etc, or maybe they rev the engine a bit more. But if the same bore and stroke, they most likely have the same overall and mounting dimensions. They could have a different crankshaft though, so check that out before you install it.



Dont know why everyone has a hard time understanding this all 358 cc flatties have the same amount of torque hence the same hp


The valves are the same its all the same its not reved higher for hp


Most came set low on rpms so they under preformed
of all the motors ive check less then a handful were set right at 3600 and some as low as 2750


The bore and stoke is the same the cranks the same valves etc the block mounting the same
same part numbers


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## paulm12 (May 22, 2015)

one clarification; I should have been more specific about the different crankshafts. The stroke dimensions are the same, but the input and output shafts vary for different vendors and different applications. This won't affect HP or torque ratings, but could impact swapping out.

thanks


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