# horizontal or vertical



## swp9459 (Dec 27, 2013)

I have an old ST724. The engine will no longer start. Put in a new carb, etc. Someone told me to put in a 6.5 HP predator engine from Harbor Freight. Originally I was going to dump the machine for 50 bucks but now I'm thinking different. 
HF has the 6.5 HP Predator horizontal shaft on sale for 99.00. I don't know too much about small engine but will learn. Does the ST724 have a horizontal shaft? Any links on youtube that show the swap?
Thanks Steve


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## YSHSfan (Jun 25, 2014)

Welcome to SBF swp......! :welcome:


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## Shryp (Jan 1, 2011)

Yes, horizontal. That is actually what the H on your H-70 stands for.

Vertical engines are what you would consider a traditional lawn mower.

A lot of people have done the 212cc Predator on Ariens blowers with great results. I have done 2 and the both worked well.

The HM80 engines used a 1 inch crankshaft, but the H70s should be 3/4" just like the Predator. Your hardest part of the whole thing will probably be getting the chute crank around the engine. The new engine will be slightly wider and might hit the crank. It isn't too hard to deal with though and most people can usually get away with bending it a bit. Some put spacers on the brackets to move it out a little. Some use u-joints to bend it.

The first thing to do before making the plunge is make sure your machine uses a single shaft engine. You should be good as I think only the compacts used dual shaft engines for Ariens.

See this board for various projects where people have put new engines on old machines:
http://www.snowblowerforum.com/forum/re-powering/


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## UNDERTAKER (Dec 30, 2013)

ALOHA from the paradise city.


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## jtclays (Sep 24, 2010)

My old '79 Ariens model 924038 had an H70 that had a 1" crank. On the older Ariens manuals they refer to it as an ST724 (no badging of the type on the actual machine). Just an FYI to measure it to be sure. Not a deal breaker at all as you can get either a 3/4 to 1" sleeve kit to use your old engine double pulley or separate 1" pulleys. I'll get the old Tec engine series numbers here in a few. Either way keep the old original double pulley even if you don't use it. NLA part that people will buy. If you can make some observations on the old engine the guys here can likely get you going to fix it or confirm it's toast.
Correction, I guess that sheave is still available but it's $90! 

Tecumseh H70 130210D SER 8286C


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## YSHSfan (Jun 25, 2014)

Here are a few:











You can also look for repower threads here at SBF that may have detailed info. :smiley-confused009: :smiley-confused009:

If the old engine is a single shaft engine it will be straight forward (I've done 2), if it is a dual shaft engine it will not be straight forward at all (I may be doing one in the future).


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## Kiss4aFrog (Nov 3, 2013)

Welcome to the forum Swp9459 :welcome:


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## swp9459 (Dec 27, 2013)

Thank you for the welcomes and the info.


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