puzzler Kohler k301 just stops

[bgsengine]

I rarely ever replaced head bolts on those unless they had specific corrosion or damage issues , such as deep rust or burning (from loose bolt/gasket over long period of run time) or actual breakage (from galling to the block) I doubt you will have any removal troubles, most cases of any troubles were due to them being seized to the block from rust/corrosion/carbon , if it runs you won't need to heat with a torch, just run it a minute or two to just get the block warmed up (but before the bolts get really hot) will usually do the trick and they'll come loose easily.... If your bolts do not show obvious signs of damage/ stretching/rust pitting/burning there's no problem with re-use. Even harder will be to find the thick heavy duty flat washers, if any go missing (and they are pricey as OEM Kohler!) , so use due care in keeping track of them...

TBH, I doubt you will even need your hand impact to remove, if you can warm the engine just a bit (I rarely ever needed impact for them, they easily came loose with ordinary 9/16" socket and ratchet, sometimes had to give ratchet a bit of a whack with hand to pop 'em loose) you may likely find the bolts around the exhaust corner to be the loosest (and the ones leaking) if the overheat is due to lean air/fuel (which raises combustion temperatures), but if due to cooling issues, more often the bolts in the middle (and the gasket) that line up closest with the "bore-to-valve" bit are the loose ones (which is where they almost always will plug up on cooling first, and people rarely ever check there for plugged cooling - it is difficult to really see, and many don't realize you got to be able to see through, as there's fins between the valve guides and the cylinder bore) - and also where the gasket fails first under a cooling system overheat failure.... So, observing the location of the gasket failure (and not assuming the bolts "just came loose") can also give you clues to what was going on with the engine performance.

[KE4AVB]

I have gave up on the local hardware stores here for a couple reasons.

1. They never seem to have metrics in stock
2. They are over priced even they do have any thing I need

I do most hardware purchases through McMaster/Carr nowadays. I was using Fastenal but they virtually closed the local branch store. You have call and make an appointment to screws and other hardware at Fastenal now. With McMaster I can a lot of the screws (bolts) at about a 10th of the cost of local purchased items and have them delivered the next business day (Mon-Fri). I just can't see my self paying $3 for bolt when I can get a lot less

Yes I usually end paying up front when I only a couple of them but later I end up needing them again for some other project.

An example is the Kohler 25 086 660-S that costs me $1.32 ea but the ones from McMaster were only $10.14/25 (.4056 ea) the last time I brought 50 of them. And usually need 8 at a time on the valve cover conversion.

Now of course these are US prices and not Canadian.

[38racing]

Ok. back at it. I did a test cut and again it ran for the full 45 minutes. towards end definitely getting blowby from breather. Decided to change the head gasket. I did a leakdown test first but struggled to determine where I had piston. Got 25% with hiss from muffler. So I pull the head. It has a mix of bolts and studs. For some reason it has 3 studs at rear that have washer and nut and then a spacer and another nut. (didn't realize that at first) . they just project through the shroud plate holes. When I loosened the top nut the studs actually came out on 2 of them. Once head was off piston position suggested I did leakdown with exhaust valve in decompression position. Considering age the carbon build up was no more than expected. I cleaned piston and valve area and the head. put it back on. I had marked the front clutch so that I could position piston down a bit ensuring exhaust was closed. Redid leakdown and got 20.5% at both 50 and 60 psi input. Good news ends there.
When I was removing top nut on one stud I dropped it. When putting a stud in I dropped a washer. Concerned that they dropped into the blower shroud. Hoping for the best I decided to start it. It fires on choke but won't stay running either choked or not AND I hear the nut and washer!
Now the problem is removing the blower shroud. Might have to pull the engine. I see the side bolts on the shroud but I expect some are down inside frame. The drive shaft to hydro connected is connected on blower side. What I did discover is that the engine is likely running way too hot as the blower screen appears to be matted solid. Gong to go back out after supper .

[bgsengine]

there are 4 bolts for the blower shroud - 2 1/4-20 that thread into the closure plate at bottom "corners" and 2 on the sides (that also bolt air duct tins to the closure plate) unless the rotating screen overlaps the shroud, it can (with some finagling) be worked off , sometimes, far enough to get any loose debris inside, but the nut and/or washer could also have gotten attracted to the charging system magnets , and with the debris screen as you described, you're better off pulling the motor and give it a real good cleaning.

[38racing]

I'm hoping that there are no charging magnets as it has generator-starter on it.

[bgsengine]

I'm hoping that there are no charging magnets as it has generator-starter on it.

Ah then you lucked out, probably will not see any magnets., so at least you don't have the worry of destroyed charging system...

[38racing]

So I shifted engine forward to clear driveshaft. Removed generator to so I didn't have to disconnect wiring to it. I lifted and turned to get at screen. I had to remove 4 bolts holding drive hub to screen hub. Then I removed flywheel bolt to get screen hub and screen off. Then I could remove shroud. The washer was there but not the nut. I did find a nut later on the ground. Not sure if it's the missing one. I cleaned things up and stupidly proceeded to replace screen and hubs only to later realize shroud had to go on first. Also discovered that right side lower bolt is shorter. Longer one hits flywheel. Next up the challenge of getting mounting bolts started.
Think it could be running hot?
https://web.ncf.ca/da229/smallengine/Kohler-screen

[bgsengine]

Think it could be running hot?
https://web.ncf.ca/da229/smallengine/Kohler-screen

Aww, just a mite warm, perhaps... (yeah, right) which would likely explain repeated blown head gaskets, possibly loose valve seats (though not that common on cast iron engines), warped heads, and spark plugs blowing out of the head, threads and all... so if your cubby avoided all or most of that, you should count it as a lucky engine. and yeah, I forgot to mention to watch out for some of them where you need the short bolts in the lower 2 spots, since longer bolts interfere with flywheel... Do check your cooling fins carefully, as those nuts would "just fit" in between fins, if they got thrown by flywheel just right, only to later (usually at the worst possible time) fall back out and damage something

[38racing]

aw shucks. The bolt I found was not flanged like I think the dropped one was. So I've had the screen off and on twice . Should I do it a third time before I bolt it down. Generator is only half back on.

[bgsengine]

Head bolt? Kohler K-series and Magnum head bolts are 3/8-16 thread, they do not have flanges.. instead they have thick, hardened flat washers (not common hardware store washers) , so if it was an original head bolt you dropped, then it'd just be a regular 3/8-16 bolt.