Burnt valve

[wheelhorse66 10]

How can I tell if I have a burnt valve in my k301 kohler. I've done everything to this engine and it won't run right to save nothing. The only other thing is one of the valves may be burnt.ive put new carb,fuel pump,new lines,and all new ignition.aint to much left to do.

[rmaynard 16,077]

When you say it won't run right, can you elaborate?

[wheelhorse66 10]

It will idle just fine but it back fires when you give it throttle.and some times it will blow back out the carb.ive done everything I know to do with it.ive tried adjusting the carb but it still runs rough.

[boovuc 1,090]

Is the throttle valve loose? If there is a lot of play in the throttle valve, it will act like that. I'll assume you changed the points and condenser. At high RPM, a bad spark plug cable will also do as you described.

Check also for a leak on the carb to intake manifold. We reuse these gaskets way too many times after cleaning the carbs and sometimes, they just won't seal.

[oldredrider 2,553]

My money is on a bad or poorly grounded condenser. Since it idles fine with no blowback thru the carb, a burnt valve is unlikely.

Also make sure the coil is wired correctly. ..points wire to negative post.

Edited March 19, 2015 by oldredrider

[wheelhorse66 10]

Ok so I put another condenser on it today and it runs and idles up and down,but it still don't sound like its opening all the way up,I tried adjusting the carb and it still didn't help.and I have another question?it keeps leaking oil around the governor.i was told they didn't have seals in them.and that I could clean the filter under the cover on the side of the motor and it should stop,but it still leaks.

[oldredrider 2,553]

Make sure the breather is assembled correctly. Refer to the Kohler service manual if in doubt.

[wheelhorse66 10]

Ya I made sure everything was on right.

[rmaynard 16,077]

Why don't you just go ahead and pull the head off and look at the valves? A new $8.00 head gasket and a half hour of your time will answer your burnt valve question.

[WH nut 553]

Sounds like its running lean to me

[boovuc 1,090]

Wheelhorse66,

 

Could you please get a picture loaded here of your governor arm to the carburetor?  Again, many things can affect and cause this issue. I had written before about a loose throttle valve but I also see you just now changed the condenser. It does indicate a lean mixture but did you also:

1. Clean the gas tank making sure the screen at the shut off valve isn't filled with rust/gunk?

2. New points?

3. New fuel line?

4. New fuel filter?

5. Run it with the gas tank cap off at full throttle?

6. Check for good fuel pump volume?

7. New plug?

8. New plug wire?

 

See what I mean by various things that can and will effect performance at full throttle let alone idle.

Hang in there. You'll figure it out! Of what I mentioned above, clean out the fuel tank making sure the screen, (if it is still there), isn't clogged then change the fuel lines if you didn't do so already with a new fuel filter. Make sure the filter is installed correctly with the arrow showing the proper direction of fuel flow. After you change the fuel lines and filter, check to make sure you have a good "pulse" of fuel shooting from the fuel pump. If it is dribbling out instead of "shooting" out while the engine is running, this is a concern and will cause a lean fuel delivery to the engine resulting in backfires, unattainable top RPM and overall poor performance.

[wheelhorse66 10]

Here is the pic of the governer arm

Edited March 20, 2015 by wheelhorse66

[JackC 617]

If it is not a compression release engine a compression test may provide some useful information.  If it is compression release engine then there is a crankcase vacuum test instead.  How about the points?  How about valve to tappet clearance?  How about worn throttle shaft screwing up the air to fuel mixture when you throttle up?  It is easy to remove the head and look for carbon and make sure the piston and valves are moving properly and there is no head warp.  Time to hit the books and go through the service manual.

[JackC 617]

Also, running our old engines on ethanol fuel is like feeding them a mild poison.  Ethanol is an alcohol that can corrode plastic, rubber and metal parts in engines and fuel systems not built to handle it.  Definitely not good for the rubber hoses and rubber carburetor and fuel pump components and diaphragms.

[boovuc 1,090]

As long as the gov is hooked up and when idling to full throttle, you see it acting  as the RPM's change. I have seen too many K-series where the PO simply bypassed it.

How about item for item in my prior post did you do or check?

[wheelhorse66 10]

Yes I went through your steps and it still just won't open up.it idles just fine but when you try to go above half throttle it just runs really rough. It's kind of hard to explain how it's running.because it runs with no popping or spitting or nothing .its just like it has no power.

[gwest_ca-(File Mod) 11,318]

Have you tried another spark plug?

 

Garry

[WH nut 553]

Clean the carb and make sure the high speed jet is clean

[boovuc 1,090]

If you manually hold the governor open, does it seem better and can you feel some resistance as it goes above half throttle?

Also another very inexpensive test is to spray some starting fluid or better yet, carb cleaner around the intake manifold/carb and listen. If you hear it "rev up" on the spray, it's sucking air and you found a big issue of not throttling up properly.

It also doesn't hurt to run it and as total darkness as possible. Watch around the points housing/condenser and the coil to the plugs. Also watch back around your connectors. Even a little loose connection or wire can cause full throttle to beak up due to vibration.

[wheelhorse66 10]

We'll I was running it some today and the exhaust pipe turned red.yes I've cleaned the carb and used new plugs.i will try the starter fluid trick.

[slammer302 2,156]

Timing off? Maybe

[boovuc 1,090]

See if carb cleaner sprayed around the intake of the carb creates a "rev". Do NOT use either for this as I had suggested before. If that is running that hot, I don't want you to ignite the either on top of the engine. Carb cleaner is safer for this. If the carb spray doesn't indicate a leak, I would again look at the carb.

When your exhaust glows, that is pretty indicative of a lean fuel mixture. You need to adjust that carb by turning the needle valve out a quarter of a turn at a time to get more fuel into the mixture while maintaining good performance.

Here is another thing to check..................get the engine up to the highest RPM it will maintain without cutting out or running poorly. When you get to that point, put your hand in front of the exhaust outlet of the muffler and feel how much exhaust pressure is coming out. If the muffler is plugged up, it can create some issues with full throttle too. Without a doubt though, the hot exhaust pipe is a lean mixture issue.

[WH nut 553]

See if carb cleaner sprayed around the intake of the carb creates a "rev". Do NOT use either for this as I had suggested before. If that is running that hot, I don't want you to ignite the either on top of the engine. Carb cleaner is safer for this. If the carb spray doesn't indicate a leak, I would again look at the carb.

When your exhaust glows, that is pretty indicative of a lean fuel mixture. You need to adjust that carb by turning the needle valve out a quarter of a turn at a time to get more fuel into the mixture while maintaining good performance.

Here is another thing to check..................get the engine up to the highest RPM it will maintain without cutting out or running poorly. When you get to that point, put your hand in front of the exhaust outlet of the muffler and feel how much exhaust pressure is coming out. If the muffler is plugged up, it can create some issues with full throttle too. Without a doubt though, the hot exhaust pipe is a lean mixture issue.

Spot on

[C-101plowerpower 1,606]

Just an idea, try changing the condensor to the other terminal of the coil, mine idled fine and ran good until half throttle, this was caused by having the condensor on the wrong terminal

[WH nut 553]

Just an idea, try changing the condensor to the other terminal of the coil, mine idled fine and ran good until half throttle, this was caused by having the condensor on the wrong terminal

Condenser  needs to be wired on the Neg. side of the coil always