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jdwilson

New Engine for 728

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jdwilson
I'm looking for an 8hp cast iron recoil start for my 728. The problem is, all I can find are aluminum with electric start and built-in alternator. I don't need all that extra stuff as my starter/generator works fine and I like the fact that if the battery is a little low, I can still use a rope to start it. Plus, it would still look original. This is the third engine going on it and I want it to last as long as the engine on my 2012. I've been mowing my two acres now for 25 years and it's still running as strong as it did the day I bought it! Any ideas? jeffery d. wilson

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PatRarick
The original engine in your 728 was an aluminum engine, but with a cast iron sleeve. These engines are no longer available. The new aluminum block engines will fit and look original. They will last almost as long if you provide a little more maintenance, such as more frequent oil changes, air filter maintenance, etc. Though the cast iron sleeved engines are not available, short blocks are. I'm not sure of the crankshaft configuration on the 728, but Briggs #397815 has a 1" crankshaft with a 7/8" step down. #396876 has a straight 1" crankshaft. This is a viable alternative. The main thing to be concerned about, is the condition of your carburetor. All other parts needed from the old engine should not have any wear to worry about. The short block (gaskets included) will cost you about $325 to $350 plus shipping. A new carb will be about $90. With a short block, particularly if you add a new carb, you will basically have a new engine when finished. Any Briggs dealer should be able to get you the short block and carb. Pat

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JeffNemes
Actually the B&S verticle engines used in Simplicitys didn't have cast iron liners until the later 4211 series came out with the B&S I/C (Industrial/Commercial) engine in the 80's. They can be identified by the chrome air filter cover and large I/C decal. There was a time when the replacement short blocks for the earlier Broadmoors had liners because the aluminum bore was being phased out so perhaps that is what you were remebering Pat.

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PatRarick
JeffNemes, As to when the cast iron sleeved engines were available on these tractors, I can't argue. That was an assumption on my part, since most of the heavier equipment of the time used the sleeved engines. The 728 may very well have had the aluminum bore engine. In reality, Briggs had aluminum engines with the cast iron liner long before the I/C engines were available. Briggs began aluminum bore engines in 1953. Cast iron liners were introduced in 1958 as a heavier duty engine, but did not have the I/C designation. At that time, the cast iron sleeve was the only difference between the two engines. The I/C designation was not introduced until 1979. It came as a package that included the cast iron sleeve, replaceable main bearings (sleeve type on vertical shaft engines, and ball bearings on the PTO side of horizontal shaft engines), hardened exhaust valve and seat, dual air filtration (paper element with foam pre-cleaner), and the quieter muffler. Since the cast iron engines already had most of these features, they were also given the I/C designation. Briggs has not phased out the aluminum bore engines. These are known as "kool bore" engines today. The I/C was offered in conjunction with, not as a replacement for, the "kool bore" engines. In fact, the Intek OHV line of Briggs engines is available in three versions; The Intek, Intek I/C, and Intek Pro. The Intek is an aluminum bore engine. The Intek I/C has the above described I/C features. The Intek Pro is the same as the I/C, but with a low oil sensor and extended oil fill. Before the introduction of the I/C designation, the only way to know if you had an engine with a cast iron sleeve, was through the basic design series number. This is the fourth digit from the right, of the engine model number. For example, the vertical shaft, eight horsepower engine with recoil start would have a model number of 190702, while the cast iron sleeved version would be a 191702. These are examples, as I do not know which design series designated the cast iron sleeve. The new 19 cubic inch, eight horsepower, vertical shaft engines are available only in the "kool bore" version. There are no I/C's available. As to short blocks, there are only two currently available short blocks for the eight horsepower vertical shaft engine. The crankshaft configuration is the only difference between the two. Both are Synchro-Balanced, I/C series short blocks. Pat

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jdwilson
Thanks for all the info guys. I think I'm going with a short block with a cast sleeve. That will make a dependable as well as durable lawn tractor out of it once again. jeffery d. wilson

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JeffNemes
Very good JDW - Be sure to check the carb throttle shaft for play - you don't want any unfiltered air leaking into your new engine! If you do replace the shaft make sure you get a new welch plug on the end secured. Try to stake it back in place with a flat chisel after flatening the bowed curve. Gas resistent epoxy wouldn't hurt either. Thanks for the history lesson Pat! For you salvage hunters out there the 19 "0" 702 designated non-balanced and the 19 "1" 702 designated syncro-balanced. The ending "2" was for recoil, an ending "7" would designate electric start.

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Al
Jeff Nemes, It is great to see you around again. I know from an earlier e-mail that you have had a plate full for a while. Just wanted to say great to "see" you around again. Al Eden On the original note, We have in the past sold engines with alum and the cast iron cyls. We have seen both in a couple of years later smoking so bad you couldn't bellieve it. When we checked the oil you could almost pull it out the fill plug with a long nosed pliers. We have also seen both versions of the engines 10 years old and no smoke or oil use. The difference, These people changed the oil every 15 or 20 hours and serviced the air cleaner often. With no pump and filter the only to get the abrasives out of the oil is changing it often. Maiintenence is more important than cast or aluminum, however only with good maintenance can you obtain the benefits of the cast sleeve. Good luck, Al Eden

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jdwilson
Just an update, I purchased a short block with cast iron sleeve from Small Engine Warehouse, part number sb397816, on wednesday 8-24-02 and received it only two days later. The price was $304 including tax, shipping, and handling. Thanks for the advice on the throttle shaft and welch plug. Now if I can only find the time to put it together! jeffery d. wilson

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