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Discussion Starter #1
I have a 1256 with a Wisconsin 12 hp engine. I have had this for only a couple of years and it has been a good workhorse for me. I have rebuilt several components (PTO, front spindles, hydrostatic trans, etc.). I have noticed of late that it burns more oil and has less power than I think it should.

How hard is it to rebuild the engine? Typically what parts would be required? How long should it take someone who has never rebuilt an engine to do the job? Is there a shop manual readily available to step me through the process?

While I am at it. I have noticed that the hydraulic ram takes longer and longer to move. I have to move the lever around to find a spot that will active the raise motion (lower seems to work just fine). I am guessing that the control valves also need to be rebuilt.

Any and all comments to these issues are welcome.

Darrell S.
 

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I have a 1256 with a Wisconsin 12 hp engine. I have had this for only a couple of years and it has been a good workhorse for me. I have rebuilt several components (PTO, front spindles, hydrostatic trans, etc.). I have noticed of late that it burns more oil and has less power than I think it should.

How hard is it to rebuild the engine? Typically what parts would be required? How long should it take someone who has never rebuilt an engine to do the job? Is there a shop manual readily available to step me through the process?

While I am at it. I have noticed that the hydraulic ram takes longer and longer to move. I have to move the lever around to find a spot that will active the raise motion (lower seems to work just fine). I am guessing that the control valves also need to be rebuilt.

Any and all comments to these issues are welcome.

Darrell S.
If you have ever tinkered with an engine before these are not that hard to rebuild. You can buy a gasket set and rings and the crankshaft seal will get you most of the rebuild parts. Some can be found on EBAY

But before you buy the parts take the head off and with the piston down in the bore inspect the bore. If it is scratched you will need a oversized piston and a bore job, which will add about $100 to the job. Sometimes the rings get old, worn and lose their tension and a fresh hone job on the cylinder and a new set of standard size rings will get the performance of the engine back and stop the smoke.

There TRA-10D manual for the engine in the reference library would be a good document to review. Your TRA-12D (ie: 12hp) would be nearly identical. http://www.mytractorforum.com/images/reference/wisconsin_manual.pdf

But this is the manual that you would want to get http://www.manddsmallengine.com/wisconsin/mm302.html

and your public library may have a good guide on small engine repair.
 

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Discussion Starter #3
I broke down and took the head off last night. Here is what I found:
1. The cylinder is clean and smooth. No scrapes, gouges, scars etc.
2. For the most part the entire head, piston and vavle area was covered with black deposits.
3. The only area not covered was about the size of a half dollar at the oposite end from the exhaust.
4. also in this same area It appears that there was at some time a very hard particle. The top of the piston and the matching part of the head have small dings in them. The dings are about 3/8" long and look like the engine ran with a needle bearing in it for a while (25-30 strokes by the look of it.).
5. There apears to be a little oily gunk on intake valve shaft. When I took the valve cover off I did not see excessive amouont there.
6. There doesn't look to be a great amount of loosness in the valves or piston. I can move them slightly by hand a few thousandths.
7. I measured the cylinder bore and independently my son measured it we both came up with 3.520 diameter.

Questions:
1. I have been told that the cylinder bore should have a cross pattern and not be shiney smooth. Should I hone the bore?
2. I was told that with bore smooth That is where I am leaking oil into the cylinder.
3. What is the correct diameter of the bore?
4. I plan on replacing the rings. I will be calling my NAPA dealer and get prices. How far apart do I take the machine and what gaskets will I need? Is there a kit I can just get with all of them in it?

Any other comments or suggestions?


Don't forget to flag your flag at half staff on Monday until noon. Then raise it all the up. We owe so much to those who gave the ultimate. This is just a small token of our rememberance.
 

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If you measure your piston at the skirt,then compare that to the bore diameter,that will tell you how much clearance there is.On a TR10D and TRA10D the measurement should be .004-.0045,yours should be about the same,if yours measures.005 or .006 it would probably still be ok but any bigger than that,it should be bored.After you do that put your rings into the cylinder,1 at a time using the piston to square them push them down about 1in from the top of the cylinder,use a feeler gauge and measure the ring end gap,the same book says .010-.020,if they measure over .020,that means either the rings or the cylinder are worn,that could be the cause of your oil consumption.Also check the top of the cylinder for a ridge but if you didn't have any trouble taking the piston out the top with the rings on,there probably isn't one.What happens is,the cylinder wears to the top of the ring travel and a ridge will form a the top of the cylinder,if there isn't any ridge,that's good.You did give a measurement for your cylinder but you want to check it top,bottom and center,2 times at each,90 degrees apart,that tells you if the cylinder is tapered or out of round,if the measurements vary by more than .003,then it should be bored.
 

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Discussion Starter #5
bstrucker - Thanks. Some good information. I printed the manual for the 10hp and will use it as a reference.

There is a slight ridge at the top. I just assumed it was some of the carbon buildup at the top of the stroke. There was a lot all over the top of the piston, compression area and the bottom of the head. I will pull the piston out tonight or in the morning before the honey do list starts. I get up early she sleeps in! I will go to Harbor Frieght and get a cylinder hone. I will use that to to knock off the rideg if it is carbon buildup. I don't want to use anything hard to scrape it and damage the bore.

Do I need to pull the engine off the tractor to get it apart? NAPA can get rings but they much be ordered. I will pull my piston out and look at my rings and piston and see what I got.

Hope I have more information tomorrow.
 

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To do the job properly,the engine should be off of the tractor,if you start honing the cylinder with the crank still in the engine,your dropping tiny pieces of metal all over it and the crankcase.It could be rinsed out and probably never hurt anything,I'd pull it off,so it can be cleaned out properly if it were mine.You have to watch if you start honing without taking the ridge out first,if it's small,the hone will take it out but sometimes it will cause the cylinder to taper more.If the ridge is carbon and there is a good possibility that it is,try spraying it with WD40,that will usually soften carbon up enough that you can wipe it out with a rag,it'll work on the carbon in the head also.If the piston isn't out of the engine yet,you really can't access what your going to need until you get it all apart and get some measurements.
 

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Discussion Starter #7
A little more info.

The piston has "+.020" stamped on the top. I am guessing that it is already 0.020 oversized. I measured the bore at various points vertically and around the bore. It appears to be at most about 0.005-0.006 out of round.

I am thinking I have a few options. I can have the cylinder bored out again.
I can just hone the bore and replace the rings. Hone the bore, put new gaskets in and run it until it dies. My wife's suggestion is to replace it with a newer machine that is more up to date and will require less maintenance.

I am open to suggestions. What costs am I looking at? What type of machine do you recommend? I do NOT need a mower. I need the tiller and would like something to move snow (FEL, blower or plow).

HELP:thanku:
 
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