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Two motors. Pros and cons?

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Two motors. Pros and cons?

Postby frascati » Mon Jan 27, 2014 7:29 pm

Which of the following two motors is a better choice for snowblower duty? Both about the same price.

I'm looking at the following two motors to replace a worn HSK70 tecumseh on an otherwise very well maintained toro snowblower.
I'll have to remove the crank and turn the shaft down to match the HSK70. I've made the measurements and there is plenty of shaft there to do so. Just a couple of hours in my shop.
These two are listed at only 15USD apart. Is the 11hp a stronger motor overall? I can't find torque curves or other specs for these.
The 11hp is listed as a "short block". Is the 11hp "OH..." designate an overhead cam? I know the 10hp is a side valve L head.

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Thanks for any suggestions.

If I find the specs for either engine I'll post them. I'm just hoping you guys might be familiar with both engines since they've been around a long time and were fairly common.
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Re: Two motors. Pros and cons?

Postby 38racing » Mon Jan 27, 2014 10:26 pm

Why not look for non generator engines to get away from the tapered shaft. I think LC makes engines to replace the snowking
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Re: Two motors. Pros and cons?

Postby frascati » Tue Jan 28, 2014 2:21 pm

Thank you but I'm going to chose between one of these two motors. I'm just wondering if anyone might assure me that the OHV is clearly the better engine for the job.
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Re: Two motors. Pros and cons?

Postby frascati » Tue Feb 11, 2014 2:37 am

Well I've got the 11hp up and running.

Is there any sound advice here as to how to run a standard engine like this in the winter, as opposed to the "snow king" or snow-version briggs? Is the mixture different? Are the governor settings different? Different spark plug? I hope someone can advise.

The distance from the shaft center to mounting base of the HSK70 and the OH318EA is exactly the same so the belts fit fine. The tapered section of the shaft is only about an inch at the end which was promptly removed with a hacksaw while running the engine. The main section of shaft is exactly 7/8 so it was a fairly straightforward matter of boring the pulley to 7/8 and then putting a couple of deep spots of tig between the shaft end and the end of pulley. Perfect fit in less than two hours of my own shop time.

I seem to only be running into tuning problems for winter temps with this. There is a clever air cleaner cover that rotates 180 degrees to either take fresh air from atmosphere or take air from a shroud around the muffler.

From initial startup, after removing the paper filter and rotating the filter box cover to the 'winter' position, I had to raise the RPM from about 3000 to 3500 with a screw tension adjustment on a spring that pulls against the movement of the governor arm.

Once I started blowing snow the engine immediately started hunting for gas. So I took it back in the garage and noticed four notches on the governor shaft side of the governor arm evidently to set the spring to to more/less sensitivity against the action of the governor. After experimenting with these notches the engine seemed to perform best at the fourth-most outer notch. But when I got into a long lane of heavy snow that required the governor to really feed the throttle for about three minutes straight it came out of that row coughing and wheezing and severely hunting for gas. hunting up and down and after about 30 seconds just died.

So I looks like I might be running too rich. Or too weak a spark? Or what?
Just what makes a "winter" version of small 4 cycle unique from it's cousins?
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Re: Two motors. Pros and cons?

Postby mwerles » Tue Feb 11, 2014 8:42 am

The heated air intake is used primarily to prevent carb icing,if the air isn't being warmed enough,this could be your problem.Next time it does this,quickly look in the carb,if able,and see if there is ice build up in the carb throat,probably at the venturi,you have to be quick because it will melt from engine heat when not running
Les
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Re: Two motors. Pros and cons?

Postby frascati » Tue Feb 11, 2014 10:42 am

I will check that. I'm afraid it's unlikely. The plastic intake on the "winter" side of the intake cover is designed pretty close to the muffler requiring all air to come in close contact with the muffler before entering the filter housing. Also, the motor will run fine for an hour of light use. It is only when the governor forces rich gas into it in order to cut through a 25ft length of wet snow that it starts coughing and hunting.... and finally quitting.

The old motor was a 7hp HSK70. This motor is an 11hp OH318EA. About 30percent heavier and much more powerful. The HSK would hit a heavy length of snow and simply chug through it at 3/4 rpm. The OH3 hits the same heavy lane of snow and doesn't lose speed at all. Using 11hp to clear a relatively narrow 24" path is pretty unstoppable. But it does not seem to like the extra gas at the same rpm that the governor is feeding it.
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