Koehler carb help please

[Westie1 29]

Fired it up and it will run with the idle screw all the way in, give it choke and it dies,  it sound a bit lumpy run with choke off and throttle shut.

I took air filter off and no change.

 

Is screw in rich or lean?

Thanks 

When I shut it down I get this odd noise, never had it from a carb before

[Westie1 29]

It seems that the air/fuel idle screw has no bearing on the mixture. Wonder it I have an air leak.

 

 

Seems I have a problem, i can feel air coming from the head above the pot. Is my air leak a head gasket?

😔

[Westie1 29]

Head gasket my issue? 

 

Genuine the best or is there a better option?

 

How do I know if it's warped/needs skimming?

Been sold a pup here lol

 

Cheers

Edited October 21, 2018 by Westie1

[Reiver 14]

Looks like head gasket has been leaking, I have found in the past that some kohler  heads seem prone to warping. A quick check of  head for warp is to place  a straight edge across head face  and look for light under straight edge. more accurate way is to try and slide a feeler gauge between bottom of straight edge and head face.check diagonally.

[Anglo Traction 1,016]

Firstly,  don't throw the old carb away. I presume this is for a 16hp K341 or Magnum?. The Carb in your pic looks aftermarket. The original was either a Kohler with #30 in raised letters in the casting above the venturi aperture when looking through past the Choke plate. Or it is/was a Walbro. Both have different settings and the later ones from the 80s had fixed Main/High speed needle jets.

I have no experience with those Chinese Knockoffs, but have heard different opinions and experiences. Is that Carb specifically for a 16hp? or a generic one which states it fits all?.

 

If the Needles actually adjust the mixtures, then the top one is the high speed/main, the angled side needle is the Idle mixture. Top screw is the Idle Speed adjuster.

Need to know what your engine model, spec and serial number is to establish correct needle settings.

Will probably need to guess or take an average of the preliminary settings for a chinese one. 

 

As for the Head Gasket, the quoted genuine Kohler ones are preferable, as they still have the folded over edges that are exposed to combustion forces.

Aftermarket ones are likely to be just a pressed sandwich style, unless you can see what you are buying. I which case, they will work ok.

 

Flatness of the head/cylinder faces are essential. you can check the head flatness after a clean on a good sheet of thick plate glass (smooth and very flat) and feeler gauges.

You should not be able to get a 3 thousandth (0.003") of an inch feeler gauge between the 2 faces anywhere around it. If can-.......

obtain 2 new sheets of non-creased Wet or Dry P400/P600 (1 of each). Proceed to flat the head gasket face down on the P400 (dry) in circular movements until the high/low merge.

Finish on the P600 the same way. The small impressions left by the original gasket do not really need to be removed, just aim for a smooth clean area all around.

Head bolts are torqued to 28-30 lbs ft  and rechecked after an hours running. 

Once the head leaks are sorted, you can sort the carb. Good luck 

 

Edit -Bit slow, Reiver beat me to it.

[Westie1 29]

Thanks that's some really great info!

The carb is specific for the 16hp single Koehler and is exactly the same as the original other than the choke being different so I have swapped it over.

The original carb I will keep as I believe it can have the throttle shaft bushed (that was the issue with it) but I don't plan on this being a purist show horse right now if I'm honest.

 

I will give meetens a bell tomorrow and ask the genuine gasket cost as they were great to deal with before.

As for the carb settings I believe 2 turns will get it running and then I will just tune as normal. There really was a lot of air escaping the head so I'm not in the least bit shocked now that the a/r screw did nothing.

 

At least I've found the problem, I'm a little wary of skimming my own head what would a machine shop charge? May make me a bit braver if a lot lol

 

I'll check 1st with my feelers thanks for the tip on that 

 

Edited October 21, 2018 by Westie1

[Reiver 14]

If head is warped you have nothing to lose by following what Anglo Traction suggests to sort warped head.It will be cheaper and more satisfying if you can sort it yourself rather than using a machine shop.

[Westie1 29]

I think I have some safety glass lying around somewhere I'll give it a go, been reading up on red square and it seems quite a common diy job.

[Anglo Traction 1,016]

This Gasket looks perfectly serviceable as an example (others are available)-  K341 .

 

Someone has de-coked that in the not-too-distant past and may not have checked the flatness before refitting, or bolted it down in the wrong sequence and torque setting.

Clearly burning fuel at a rich setting, as the exhaust valve should be pale fawn/white colour. The good news is, it is not yet burning any oil from worn rings or cylinder.

  

You should not have a problem cleaning the face up on the head. It's quite straight forward.

Just take it slow and let the weight of the head sit on the W or D paper when circulating it. You can use a P320 grade or P240 if it's rough to start, then progress to finer grades.

No need to press down hard on it.

Use a brush to clean the dust out of the paper regularly (use a mask). If you find it hard to tell the high/low spots, use a coloured felt tip pen to highlight them.

I had to learn and have done all my engines that way, even if they didn't need it. I had to start with examples like this-

 

 

to this-

 

Done properly, you won't need to revisit it after.

 

 

[Westie1 29]

Good grief that's some transformation!

What did you use to remove the carbon from chamber piston and valves?

 

From what I have read this is a result of the throttle shaft play running it lean and warping the head so with head sorted and it's new carb I should be sorted....hopefully.

 

Any tips on cleaning up the outside ready for engine paint? You seem well versed in these things.

 

Much appreciated 

[Stormin 4,458]

To remove carbon, I use an old 6" rule very carefully. Also a piece of brass strip. I finish off with Scotch Bright or wire wool. For the outside, wire brush, scraper and plenty of patience.

[Anglo Traction 1,016]

24 minutes ago, Stormin said:

To remove carbon, I use an old 6" rule very carefully. Also a piece of brass strip. I finish off wi.th Scotch Bright or wire wool. For the outside, wire brush, scraper and plenty of patience.

 

Yep!, and just to embelish what Norm says, the basic rules are - always use a metal that is the same as, or softer than the parent metal (unless you are very careful).

Hard Carbon can be removed easier after soaking with various types of oil. I use an old brand called Redex, but even WD40 will assist it.

The added advantage of this is that the bits of Carbon will stick together and to the scraper, rather than fall down gap like the side of the piston.

I found bringing the piston to top dead centre.  Cutting a strip of card that is just thin enough to fit down around the side of the piston.

The length of the strip depends on the piston diameter. In your case, it needs to be almost exactly 300mm long and probably 7mm wide.

Clean gap out first with a piece of pointed plastic of the same thickness. Add engine oil to the gap around the piston and set the cardboard down around the gap.

This will stop most of the carbon rubbish being trapped there while cleaning the piston crown off.

 

I stuffed pieces of rag into the bolt holes and removed afterwards. Clean the cylinder gasket face and valve area first, then do the piston crown last.

Clean the piston, then remove the cardboard with any bits still stuck to it. Wipe area again with a lightly oil moistened lint free rag. Add oil around the gap again.

Lower the  piston in the cylinder and wipe any remaining bits of oil/carbon away. Re-assemble.

 

Just a note on your point ref the worn throttle shaft, yes it can be a running issue, but it's affects are assuming that-

-the Air Filter is new and not clogged.

-the Carb is at least set to the correct preliminary settings and the ignition is correctly set. Only then will the engine be running lean with extra air.

It will also run hotter, which will show up on the exhaust valve colouring. In your case the exhaust valve is black which indicates running rich.

 

I suspect your Air Filter is not new, as the extra air through the throttle shaft is being compensated by the lack of it through the filter making the mixture rich.

Hope I explained that clearly for you.

Good luck and let us know how you get on.    

   

      

[Westie1 29]

Fantastic help the knowledge on this group in amazing, thank you.

I will clean as you have described and will be sure to update on the results when done. 

 

It came with no air filter or housing sadly so I can't comment on that (now obtained) and it had some other bits broken or missing but was 99% complete.

I dont know it's history but seems to be a sad one, new lease of life with me now.

[Westie1 29]

After many hours with course grit wet and dry (still not completely done, it was like a banana!) I'm still not quite done. 

 

My head gasket turned up and isn't a perfect fit with the combustion chamber.

Is this a problem or not?

Thanks

 

[Stormin 4,458]

  Not a problem with that, Rob.

[Westie1 29]

Smashing I thought best check cheers mate.

I best finish this high comp head now lol

[Westie1 29]

After about 5 hours with 240 grit I'm still left with this, does it have to be perfectly flat or will the head gasket make up for some? Loosing the will to live and been through lots of paper. Wish I could get bigger sheets than A4

 

[Anglo Traction 1,016]

Comparing what you started with, it looks a whole lot better. I have never seen one that badly distorted. 

In an attempt to be practical and honest, I can't help thinking that it needs more done to prevent further leaks?, but I'm a pretty fussy over-cautious person.

 

If you stop there, call it a day and fit it, there is a risk it will leech gasses past the gasket to the two uppermost, red circled bolt holes. I can''t say what the level of risk is. 

At least the head would not be distorted again when bolted down to spec (unless the cylinder gasket face is not flat). 

I can't be sure but I think those 2 bolts go onto blind holes?, so may contain any further leaking, but will make it difficult to remove them in future.

The 3rd red circled hole with the black arrow carries the bolt which I believe sometimes breaks into the Exhaust outlet chamber. That looks like it would be ok, as you have a small, clean flat face between it and the head chamber.

  

 

I understand/admire your self disciplined, marathon efforts to get to this stage, but it's your call really.

Maybe if you could continue at least to the point of obtaining a flat 'land' on the chamber side of those two top circled bolt holes?.

It may help if you place the head down on the paper and presuming you are right handed, place the palm of your hand (ball of your thumb) over the Spark Plug hole area, you can apply slightly more pressure to that area and less over the opposite end. You would emphasise more localised metal removal that way and still achieve flatness.

 

I don't think there is any issue with Valve (lift) Head clearance as a result of metal removal, but it would be worth checking anyway.

Just wondering if you have obtained/downloaded a copy of the K series Engine Service Manual?. It's very helpful.

Keep at it, you'll be rewarded with a better running Kohler in the end.  

   

[Westie1 29]

Thanks Anglo, I think deep down I knew the answer as you have rightly pointed out.

I've just bought a frozen pizza, 4 bottles of cider and 3 sheet of 180 grit. The wife's off out tonight and when the little ones in bed the effort resumes lol.

I believe I have downloaded the manual along with the specific wheel horse manual and transmission manual from various places. I need to print them off so there a little more usable.

 

To help prevent it in future I have a working carb and won't be painting the cooling fins then fingers crossed.

[Stormin 4,458]

  I'm with Richard. Really needs more work. Do as he suggests. Ship and a 1/2 pence of tar and all that.

  As for painting the block, I used BBQ paint on the Black Horse. Still looks fine.

[Westie1 29]

I've got the tins off ECT and an old battery charger on the way to try electrolysis. Then I'm going to paint it all in vht but leave the fins. I would like to remove the pto and flywheel to paint but don't want to cause myself issues.

[Westie1 29]

After burning through 3 more sheets of 180 grit I have flatted all but the depression from the previous gasket. It was much better quality paper I'll buy more Monday. 

[Anglo Traction 1,016]

To be honest, I would say you are there with it. Hopefully the new gasket rolled lip will sit in the same depression area remaining.

You have enough flat area for a gas tight joint now. The original pic of the head showing the blown gas leak areas, which I later showed and denoted (but forgot to explain) with green arrows are now fine.

There is just the chamber carbon deposit areas to finish back to bright and you're done with the C/head.

Nearly time to arm yourself with a torque wrench and bolt it down to the sequence in the manual. 

 

[Westie1 29]

Thanks Anglo 

Looking at it I think I'm going to be going at it quite a lot to get rid of the last bit completely, it seems to slope towards the very edge. I might just try 1 more sheet and then leave it there if no better then if your saying it should be fine.

 

I'm going to get the rest cleaned up and find the sequence in the manual I downloaded.

I've got some copper rtv silicone I'm going to use too.

 

Would you reuse the head bolts and if not can I use any that match the original dimensions?

 

How should I clean up the cylinder(that's on the engine and on the tractor)? I could use glass with wet and dry but the slurry would do the cylinder ECT no good.

[Westie1 29]

Nothing would touch the carbon other than the rotary tool with a steel wheel and wd40 after a screwdriver scrape (I was very careful with both). Lots of dings in the head so figured I can't make it any worse. The piston going to look like the surface of the moon I bet.

Think I'm done on this now after 1 more sheet for good measure tomorrow