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dratkinson

New/old 728, old motor problems

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dratkinson
I recently bought a 728 with engine model: 191701, type: 0121-01, code: 700731. The tractor is in pretty good shape and cuts wonderfully. However, it uses about 1/2 quart of oil per tank of gas and smokes like a banchee! Should have no problem with West-Nile mosquitoes this year. :) Question #1. Should I maintain the 50-hour oil change interval? :o) Question #2. What is the best book to teach and walk a novice through the process of rebuilding this motor? At Jack's Small Engine, I found a "Briggs Repairman's Handbook, engines models 1919? to 1981". Will this book do the job, or is there another that you all prefer more? /r David in Denver

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D-17_Dave
All you should ever need for the older engines is the Briggs manual you refered to. It is packed with info on all the older engines. I think a week point on the older vertical shaft engines was the valve seats getting loose and falling out. Your problem certainly sounds ring related, but if you plan on a rebuild, don't forget to check things like valves and such. You don't want to go o the exspense and trouble of a teardown and rebuild only to have major damage later on.

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Ronald Hribar
There are tolerances that should be maintained in rebuilding a motor. Unless you are familiar with doing this, I feel it would be more apporiate on taking to a shop and having it done right the first time. The motor will last a long time if done properly. Having the manuals will acquaint you with the motor. And you can ask proper questions or have parts rebuilt and you can assemble it yourself. There is very little in life that is more satisfying than starting a motor that you put together yourselve.

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dratkinson
All, So, would you all then recommend that I: buy the book, take the motor apart and diagnose as much as I possible can, take it to a Briggs authorized repair facility for any machine work required, buy the seals, tools, any new parts, etc., and reassemble it myself? I did something like this 30 years ago when I stopped the oil consumption on a worn-out Honda 350 CL. But, its been a long time since then. /r David in Denver

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papamerkle
The Briggs book will tell/show all you need to know to repair the motor. I would do a few things before I take motor apart. 1. Pull spark and look at it. Here is a good site to diagnos the condition of you motor: http://www.autolite.com/tech/PlugTips.pdf 2. Do a compression check. 3. How often do you pull shields and clean fins? Grass build up in fin area will cause motor to run hot and use oil/smoke. 4. Pull head and look at cylinder wall. If there is scratches/grooves in cylinder wall, I would be pulling motor apart. 5. If the cylinder wall looks ok check the crank case breather. It can cause motor to use oil. I change oil in all my small motors every 25 hours.

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dratkinson
Papamerkle, Oh, you reminded me. When I first got it home, it would not start, so I pulled the plug to check it. The plug was covered in oil and completely carbon fouled. I cleaned the plug (didn't have another) and put it back in. I checked the oil level and it was full, but the oil was very thin and smelled like gasoline. I suspected gas was running through the carb, so I installed a shutoff valve and see-through gas filter. Changed the oil... When I then tried to start it, it fired up okay. It just smoked a lot. So, okay...I'll order the book and start from there. Thanks all. /r David in Denver

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