Briggs Guys, need help............17.5 Intek issue

[TP from Central PA]

Hello, I got a small shop where I do machining and ag/construction equipment repairs and with that I do get some outdoor power equipment as well. Recently got a 17.5 hp single cylinder Intek in on a small White(Mtd) ZTR...............was coughing out oil, assumed it ate a head gasket, which after tear down was correct. In talking with the owner it was previously replaced not long ago, and I found who ever did it must have scrapped the old off with a putty knife, because the gasket surface on the head was all scored up from what ever "Tool" they used. Decided to setup the head in the mill and take a skim cut to clean up the surface, which I did. Installed it with a new gasket of-course. Since it was off the machine, he wanted it re-ringed, so we honed and did that as well. All new gaskets, installed valve seal, adjusted valves to proper spec's. After the engine was back on the machine, it fired right up, smoked a bit but I assumed that was oil residue in the muffler, as it quit fairly quickly. Figured all was well. Re-checked torque on the head, re-checked the valves, everything looked great................Went to move it the other morning, and guess what, still some blue smoke on start up? Oil is still full on the stick, and it stops fairly quickly but it still is smoking on start up and clearly isn't right. Issue is I am not sure what could be the issue? Rebuild quite a few engine in a year and usually know what to do if something is wrong, but not sure on this one. Could anyone point me in a direction of what/where to look? Thanks

Oh, forgot to mention, valves were lapped and checked out good.

 

[Tinkerer200]

Did you check the end gap of new rings when you were installing them? IF so, what was it?

Walt Conner

 

[TP from Central PA]

Did you check the end gap of new rings when you were installing them? IF so, what was it?

Walt Conner

Been a few days, don't remember exactly but did check them, I didn't grind them to widen it.

 

[Tinkerer200]

Well I wouldn't expect you to have ground them, I would expect the end gap to already be unexceptionable. Might also want to check that gas is not leaking into the oil. Turn the gas off a few seconds before shutting off engine, no gas shut off, add one or pinch the fuel line with vice grips then see if it smokes yet next time it is started.

,Walt Conner

 

[ILENGINE]

Lets see you have a newly hones cylinder, which I hope you cleaned the cylinder real well after that, and new rings and you are getting a small amount of smoke at start up. Could be just a case of oil seeping past the rings when it sets, and gets burned off. there are a lot of new engines that do that exact same thing, I wouldn't worry about it, and just run it and see if you have excessive oil consumption, which according to the small engine manufacturers is an ounce an hour.

 

[7394]

Honed it a bit ? Did you mic the cylinder in a couple different places to see if you needed to bore it to next size ?

What about valve guide spec to valve stem ?

 

[TP from Central PA]

Yes, cylinder was honed. Did not mic the bore as I felt with the cross hatch pattern from the factory still being very nice, it was not even close to going over bore on it, not to mention it only has 190 hrs on it. After honing it was washed with warm soap water to wash the grit away and let dry. The crank case ventilation system also looked good. Valve guides were also tight, and I did not bother measuring them. Again with only 190 hrs I find that crazy any parts would be worn beyond spec, especially knowing the owner is very fussy on his service intervals.

 

[DaveTN]

Just wondering if you checked valve guide wear as 7394 suggested? That will let oil get pulled into
the cylinder and burned on start up, but then usually goes away when the valves
and guides and all get warmed up and expand and reduce clearances. :thumbsup: