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917 Long Awaited Work


Austin

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After the few months of being stashed away, I decided to give the 917 a look. I knew (know) at the very least it has a bad head gasket which will be swapped out soon. In addition to a bad breather system. Potentially do to blow-back which I believe it has, as oil is liberally covering the seat of the air filter.

So a quick call to Sandy Lake Implement and it now has a new-breather assembly and new gaskets for it. (Hope I installed everything right 😬) The plan is to have the new head gasket in by the end of the week, maybe even running. The rings still need done as far as I know, but if I can at least get it running again first I'll deal with those later. Come to find out unbolting and lifting the engine to get the three inner bolts for the head cover off, might have been easier than sitting with my hand awkwardly bent up through the frame for an hour.. Oh well live and learn I suppose. Thankfully I only lost one bolt/screw in this process. One of the 4 for the air filter seat but I didn't see it inside the carburetor so that at least is a plus. 

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Definitely has the normal buildup of crud. I don't recall that when I have replaced those kind of breathers, that the reed valve style included the mesh filter. 

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12 hours ago, Chris727 said:

Definitely has the normal buildup of crud. I don't recall that when I have replaced those kind of breathers, that the reed valve style included the mesh filter. 

I would’ve thought the replacement would have been the same as what I took out. I had Brenda order the parts and that’s what’s she found for me. Two new gaskets, the mesh, and the new plate. We shall see how much better it works.

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The reed style valve you are showing is installed incorrectly.  You will have problems like that.  The mesh filter does not go under the valve and will not allow it to close.  Also, the air filter bolt.  Be sure it isn't in the throat of the intake.  I have an M20 (same basic engine) in a Sunstar I picked up firing on one cylinder.  It had eaten that exact same bolt and it became wedged between the valve and seat.  They just don't seem to have much compression like that.  :)  Had to re-grind the valve and seat and all good afterwards.  But the breather definitely needs to be corrected or you will have major blow by.  Good luck!  Great engines in my opinion.

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 I seem to recall there being a problem with valve breathers for some of the KT engines but not sure if it was the KT or KTII. Maybe someone will recall better than I. I noticed the same problem as Brettw mentioned on the way the breather is assembled. That reed needs to lay flat against the body to do what it is there for. It is a check valve that allows air movement one way but not the other.

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3 hours ago, Brettw said:

The reed style valve you are showing is installed incorrectly.  You will have problems like that.  The mesh filter does not go under the valve and will not allow it to close.  Also, the air filter bolt.  Be sure it isn't in the throat of the intake.  I have an M20 (same basic engine) in a Sunstar I picked up firing on one cylinder.  It had eaten that exact same bolt and it became wedged between the valve and seat.  They just don't seem to have much compression like that.  :)  Had to re-grind the valve and seat and all good afterwards.  But the breather definitely needs to be corrected or you will have major blow by.  Good luck!  Great engines in my opinion.

So the mesh should sit on top off the black-tab (valve). So the valve will cover the hole, and then the mesh cover the valve? And I’ll be sure to take the carburetor off and check the intake. A good carb cleaning wouldn’t hurt either, as it’s sat with ethanol gas and I’ve never cleaned it. I loved this thing before it started having issues. Definitely beat the old B112 I had, though I still wouldn’t mind it back.

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36 minutes ago, Tarheel said:

 I seem to recall there being a problem with valve breathers for some of the KT engines but not sure if it was the KT or KTII. Maybe someone will recall better than I. I noticed the same problem as Brettw mentioned on the way the breather is assembled. That reed needs to lay flat against the body to do what it is there for. It is a check valve that allows air movement one way but not the other.

I believe it was the KT but I might be wrong. This is a series one so that might explain part of the issue. So as I asked Brett : 

The reed/valve covers the hole in the plate, and then the mesh covers the Reed/valve? If so I can get it “fixed” tomorrow, or at least changed to see if I get it right this time.
 

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LOL Sorry sir, I really can't recall where the mesh was located but I would assume over the reed and opening. It is raining here (Through Saturday) but if I get the chance, I'll pull a breather and let you know. I haven't had one apart in over 30 years I guess.

 I wish I could get you some pictures but about the time I learned how to do so with my phone, my carrier dropped the phone type I was using and I can't figure out how to find photos and get them off the phone and onto the computer (with the new phone). If only there was a 10 year old kid around LOL. Heading out to the shop now and if the rain allows, I'll try and get one of those KTs pulled inside and find out.

Edited by Tarheel
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I believe most of the Kohler opposed twins (even into the Magnums) had a rubber "umbrella valve" which dry-rotted and failed. This is why they chagned to the reed valve. 

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1 hour ago, Chris727 said:

I believe most of the Kohler opposed twins (even into the Magnums) had a rubber "umbrella valve" which dry-rotted and failed. This is why they chagned to the reed valve. 

 Exactly what I just found.

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9 hours ago, Chris727 said:

I believe most of the Kohler opposed twins (even into the Magnums) had a rubber "umbrella valve" which dry-rotted and failed. This is why they chagned to the reed valve. 

That is what my engine had. Mine kept blowing out of the hole in the other side of the breather plate.

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From my shelf spare unused M18 still umbrella style.  Umbrella vent towards the PTO shaft.

Foam block to the flywheel side underneath the vent tube to air filter housing.

Breather.thumb.jpg.d031b27409afa7c39bbb17f22a6b84e0.jpg

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1 hour ago, GregB said:

Umbrella vent towards the PTO shaft.

Foam block to the flywheel side underneath the vent tube to air filter housing.

Just what the KT Service Manual shows:

image.png.258f0042af524d380d8294cb77189f7f.png

2 hours ago, GregB said:

From my shelf spare unused M18

Drop that into your 16GTH-L and you'd have a better than OEM 17GTH-L.  sm01  Wouldn't even have to change the ignition switch back!

Let the 16HP Briggs have some shelf time. 666

 

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2 hours ago, GregB said:

From my shelf spare unused M18 still umbrella style.  Umbrella vent towards the PTO shaft.

Foam block to the flywheel side underneath the vent tube to air filter housing.

imageproxy.php?img=&key=3d214da05fced21aBreather.thumb.jpg.d031b27409afa7c39bbb17f22a6b84e0.jpgimageproxy.php?img=&key=3d214da05fced21aimageproxy.php?img=&key=3d214da05fced21a

Thanks for that! I definitely have it set up wrong. I’ll get it corrected later. 

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Bill,

The thought has crossed my mind. 

But with everything else that seems to be breaking around here, if it not broke do not try to fix it sm03

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Thank you all for the help on the breather. It has been corrected so that I believe I have it set right now. Just needs a head gasket to be installed now and it “should” be a good runner again.

Edited by Austin
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