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mattd860

Rebuilt Kohler K301 Issues

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Check with Brian (KB9LOR). He should be able to get you carb parts. There are also bushings and screws available on eBay for repairing the throttle shaft.

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Good info on this thread. The carb IMO would have to be very worn to cause this. I would lean more towards the oil in your gas as an issue also. Gasoline, can evaporate if sitting too long. And if there is enough wear in the carb, air can get in while sitting, evaporating the gas. Leaving the oil, it won't run on oil. Also IMO if you have alot of popping when throttling down , it is leaning out. Terry, have you ever seen where the reed valves harden? I've had that happen on 2 cycles but I am not sure on these. And IMO chrome rings are really not a problem. It may take a little longer for them to "seat". But I use them ,fully understanding this. I agree, you probably need to break it in. When you pulled the plug, there weren't droplets on it were there? If so, water. As much as I would like it, they won't run on water. Just some more things to add to the confusion :banghead:

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Good info on this thread. The carb IMO would have to be very worn to cause this. I would lean more towards the oil in your gas as an issue also. Gasoline, can evaporate if sitting too long. And if there is enough wear in the carb, air can get in while sitting, evaporating the gas. Leaving the oil, it won't run on oil. Also IMO if you have alot of popping when throttling down , it is leaning out. Terry, have you ever seen where the reed valves harden? I've had that happen on 2 cycles but I am not sure on these. And IMO chrome rings are really not a problem. It may take a little longer for them to "seat". But I use them ,fully understanding this. I agree, you probably need to break it in. When you pulled the plug, there weren't droplets on it were there? If so, water. As much as I would like it, they won't run on water. Just some more things to add to the confusion :banghead:

There is definitely a ton of popping and backfiring when throttling down. This is why I just rebuilt the carb last week. I managed to reduce the backfiring to popping by cleaning and rebuilding the carb but the hard cold start remained. The carb is worn - I know that. However, before the engine rebuild (and in warm weather mind you) the engine started very quickly and idled very low.

There are one or two brand new Walbro carbs for sale on ebay. I might just buy one of those...

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Is it worth getting a fully adjustable brand new Walbro carb instead of a fully rebuilt Kohler car from brian miller (http://gardentractorpullingtips.com/a1carb.htm)? I would like to save money but I'm tired of buying cheap parts and and getting terrible performance.

Note - The brand new walbro carb is half the price of brian millers.

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I can get the throttle shaft repair kits, if interested shoot me a PM.

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I can get the throttle shaft repair kits, if interested shoot me a PM.

thanks for the offer. at this point i just want to get a new or fully rebuilt carb. i need nore than a throttle shaft and i want some peace of mind about this.

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I took the head off this morning to get it checked for warpage and noticed that the piston is a little 'loose' in the cylinder - at least in my opinion. I can actually wiggle the piston side to side. This is my first ever rebuild so I don't really know if this is normal or not.

I shot a video of the piston. Take a look and let me know what you all think. Thanks!

th_P1030358.jpg

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does it move like that at TDC

I will have to find that out later when I get home from work :thumbs:

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When you had the cylinder bored & honed, the machine shop should have measured the clearance between the piston and the cylinder wall. The measurement should have been .007 to .010. The measurement is taken at a point just below the oil ring on the piston, and approximately 2-1/2" below the top of the cylinder. Measurements can't be done accurately with a feeler gauge. A set of micrometers must be used.

From the video, it sure looks like you have a lot more than .010 clearance.

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When I had the machine shop bore & hone I didn't yet purchase the new piston. I wanted to wait and see if .010 over was enough since the engine was badly worn before I brought it in. So they had nothing to measure and never asked for the piston to measure either.....

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I check this thread daily and am learning a lot, so keep the posts going.

I took my piston to the shop that did the machining and they measured everything. I don't have acces to pictures or video on this computer (work thing), but I have no play in my piston at all.

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I check this thread daily and am learning a lot, so keep the posts going.

I took my piston to the shop that did the machining and they measured everything. I don't have acces to pictures or video on this computer (work thing), but I have no play in my piston at all.

I'm glad you are learning something! I am learning too but the HARD WAY!! I am really getting frustrated with all of this but I'm plunging forward.

Even though the machine shop didn't have the piston, I have to believe the tolerances should be tighter than that! They probably bored the cylinder .010 over the existing worn dimensions rather than .010 over the factory standard (unworn) dimensions.

The most frustrating thing of this is that in the end I don't have a fantastic machine - just a plain Jane C-81 8-speed with 12hp motor. My goal before the rebuild was to sell it for a Hydro but I could have bought two Hydro tractors for the price I've already spent on the rebuild alone!!!!!!!!!!!!!!! :thumbs: :thumbs:

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Every good machine shop has the book on Kohler engines. If they don't, I would not trust them to do my machining.

It doesn't matter though what is being bored, they should know that a .010 over bore means .010 over the standard bore, not .010 over what is already there. When they used the inside micrometer to measure the bore, they would have come up with a number that tells them how much is needed to true the cylinder. Then they should have told you that you needed either a .010, .020 or .030 over piston. They should not have even started until you gave them the piston and rings.

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Every good machine shop has the book on Kohler engines. If they don't, I would not trust them to do my machining.

It doesn't matter though what is being bored, they should know that a .010 over bore means .010 over the standard bore, not .010 over what is already there. When they used the inside micrometer to measure the bore, they would have come up with a number that tells them how much is needed to true the cylinder. Then they should have told you that you needed either a .010, .020 or .030 over piston. They should not have even started until you gave them the piston and rings.

Well lesson learned on my part I guess. I gave them the block and a few days later they called and said .010 over would true the cylinder but never asked for the piston or rings!!!

I contacted wheelbearing here who lives in the same town that I work in. I will find out what his machine shop is and go to them.

Tonight I am helicoiling the sparkplug hole and I will test the compression. If I have good compression should I just run with what I have or start over again?

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I check this thread daily and am learning a lot, so keep the posts going.

I took my piston to the shop that did the machining and they measured everything. I don't have acces to pictures or video on this computer (work thing), but I have no play in my piston at all.

I'm glad you are learning something! I am learning too but the HARD WAY!! I am really getting frustrated with all of this but I'm plunging forward.

Even though the machine shop didn't have the piston, I have to believe the tolerances should be tighter than that! They probably bored the cylinder .010 over the existing worn dimensions rather than .010 over the factory standard (unworn) dimensions.

The most frustrating thing of this is that in the end I don't have a fantastic machine - just a plain Jane C-81 8-speed with 12hp motor. My goal before the rebuild was to sell it for a Hydro but I could have bought two Hydro tractors for the price I've already spent on the rebuild alone!!!!!!!!!!!!!!! :thumbs::thumbs:

Two thoughts on that:

1 - there is no such thing as a plain jane wheel horse. That thing you have has 12hp kohler - when running right will out perform anything at the big box stores - and - you have an 8 speed trans with 1 1/8 inch axles - best transmission ever made

2 - if you got the hydro you would still be putting money into it for some reason or another - so no worries about the cost.

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With the play that you have in that piston/bore combination, I would not just put it back together. I would take it back to the machine shop, have them inspect the bore for damage, remeasure it and the piston. If the bore is too big for the piston, you will have poor compression, burn oil, and eventually tear up both the piston and cylinder.

You have a great engine in a K301. Talk to the owner or manager of the shop that did the work and explain that you didn't know that you should have the piston present when the block was bored, and that no one from his shop told you that you should. See if he can make it right for you. Never hurts to ask.

If he won't do anything for you, I would find another shop. You might have to bite the bullet on this one.

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I can get the throttle shaft repair kits, if interested shoot me a PM.

thanks for the offer. at this point i just want to get a new or fully rebuilt carb. i need nore than a throttle shaft and i want some peace of mind about this.

Don't blame you there, I woould buy one for myself, except my distributor doesn't sell the Carb I need lol!

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Ok I just fixed the spark plug hole and bolted the head back on just so I can read the compression.

Compression is 55psi.

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Because that engine is equipped with ACR (automatic compression release) you won't be able to get an accurate compression reading. However, with new piston, rings, and valves, even with ACR, 55 psi seems low. My K241's read between 80 and 90 psi.

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Because that engine is equipped with ACR (automatic compression release) you won't be able to get an accurate compression reading. However, with new piston, rings, and valves, even with ACR, 55 psi seems low. My K241's read between 80 and 90 psi.

Yeah i'm going to strip it back down and bring her back to the machine shop.

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That's a good decision. Let us know what they find. Keep us posted.

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