Craftsman Lawn Vacuum

[Luffydog]

Have to agree about the Kohler's croaker engine leaking can't get them to stop.

[lefty]

Thanks. I got some of the non cork material coming in Monday so I guess I'll go with that. Just for future reference, is there anything the cork material is good for?

[bgsengine]

Just for future reference, is there anything the cork material is good for?

Gearbox gaskets pretty much - grease sealing - cork is too porous to be good for much else.

[lefty]

I thought this would be an appropriate place to post this because I got the exact same machine here again. Well not exactly, different owner but same model. Looking to see if my diagnosis/hypothesis has any merit.

Owner says needed starter fluid to start and ran crappy. The machine is filthy. Oil all over it, clumps of pine needles and dirt. Airbox full of oil, oil was low and black. I noticed that one of the head bolts had backed out about 1/2 inch. Leak down revealed an obvious head gasket leak. (L-head engine). The rest of the bolts were just a bit tighter than hand tight. The head gasket was broken around the bolt hole on the bolt that had backed out.

I'm guessing that the head gasket broke causing repetitive expansion and contraction and vibration caused it to back out. Figured the rest followed suit as the clamping pressure was now uneven.

Am I close?

My second question is, what's a possible cause for all the oil in the airbox? Could it be related to the blown gasket and loose head? Bad breather or some other potential issue? I'm planning on removing the flywheel to get a look at the breather shortly. It's the round type on top.

Thanks

[bgsengine]

I'm guessing that the head gasket broke causing repetitive expansion and contraction and vibration caused it to back out. Figured the rest followed suit as the clamping pressure was now uneven.

Am I close?

Sorta, but bass-ackwards. Overheating thermal expansion and contraction causes those head bolts to come loose, usually caused by poor maintenance especially to the cooling (The flywheel screen is also part of cooling system, it needs to be kept clear, not just a regular cleanout of cooling fins every so often). Loose head bolt causes blown head gasket. *edit to add* Note that head bolt, I will bet anything it is the lower corner, close to the exhaust area, which is the hottest corner, and even hotter when it isn't getting enough cooling..

My second question is, what's a possible cause for all the oil in the airbox? Could it be related to the blown gasket and loose head? Bad breather or some other potential issue? I'm planning on removing the flywheel to get a look at the breather shortly. It's the round type on top.

Thanks

Yes blown gasket can cause excess oil use, but oil in air box is lack of maintenance , oil pumping through breather, if air cleaner gets too dirty , air starts sucking in from crankcase, and brings oil with it. Bad breather can be a cause too (more likely plugged drain holes in breather) as well as tipping mower on side (oil flowing past breather and into air cleaner box) - Overall I'd say most all of your problems would have been prevented by better maintenance.

[KE4AVB]

It been several years since I have work on a vertical L-head but if I remember correctly a bad exhaust valve guide can also cause excessive oil in the breather so I wound be checking it while you are replacing the head gasket. I never could get the valve guide go/no go gauge to work. Most of the valve guides were worn out before the gauge would go in so I go by feel nowadays.

Besides it is a good idea to check the valves for clearances and other wear anytime you got the head off.

[lefty]

That must be it then. This was probably the most poorly maintained machine I've seen since I've started working on stuff. The air box was all clogged up. I've given this machine a good cleaning and will give the owner a good talking to regarding maintenance. Thank you BG.

I'll also check those clearances tomorrow KE4. Thanks for the tip.

Should I be concerned about warpage given the fact that the head was so loose?

[bgsengine]

Should I be concerned about warpage given the fact that the head was so loose?

In my own experience (which is a LOT of those, and similar Briggs.. used to go through 30-40 head gaskets a year) , it was fairly rare to find them warped beyond reason, there were some that ran that way so long (more often on Kohler K-181 engines) that the head gasket blew through completely and then started melting a notch into the head gasket surface.. but that was pretty rare as they usually didnt get hot enough due to the poor performance once head gasket started leaking.. maybe a few here and there that warp was so bad (usually warpage between multiple bolt holes I had to run heads over some 600 grit wet-dry paper on a flat pane of thick glass (using water to lubricate things) but most of the others there was sometimes a bit of warp that was self-correcting once you torque the head down in proper sequence... never had problems with those that didn't have warp between bolt holes

[lefty]

Reason I ask is that I held this up to the light and could visibly see it out of wack. Kind of wavey. I'm able to get a .009 feeler gauge in there when I hold a straight edge the long way. Is that too much? Or can I get away with sanding and torque?

[bgsengine]

Reason I ask is that I held this up to the light and could visibly see it out of wack. Kind of wavey. I'm able to get a .009 feeler gauge in there when I hold a straight edge the long way. Is that too much? Or can I get away with sanding and torque?

It's kind of a judgment call.. takes experience and understanding how the gasket you will be using will handle the sealing of the surfaces.. if you got a straightedge over gasket surface and bolt holes over at least 3 holes, and see gaps between holes then it may require some sanding.. one trick if you have any doubt is make sure you have a hard, perfectly flat surface, and some extra fine (As I said I used 600 grit wet/dry paper) sandpaper and give it a few scrubs , you can then see from the sanded and non-sanded areas where your warp is at.. .009 is quite a bit though but it depends on where that .009 is measured at.. if you do end up sanding head, you might wanna practice on an old scrap head first to refine the technique.. if it needs a lot of work, you can rough it in with some coarse paper(maybe 120 grit) until you start getting some scratches on the low spots , then finish it off with finer paper (220 grit would be as coarse as I'd go for a finish sanding) - works best with wet/dry paper, and keep dropping water on the paper as you work the head over it, and rather than circular motions you can twist (at the wrist) while sanding back and forth, and then rotate head 45 degrees , sand some more, and so on - basically less effort in sanding back and forth and by rotating head around a bit at a time, you'll get a more even pattern with less elbow grease.. depending on the gasket being used (metal clad does not handle filling warpage gaps as well as the graphite ones, but metal clads are more durable and even in a pinch, re-usable) you don't need to get the head perfectly flat. also be sure when you are doing your flatness check the head is perfectly clean and all trace of old gasket is removed (Obviously..)