Wow! Lots of articles on this forum about Reed valves. After reading them I can see why. A fair amount of disagreement about how to diagnose and inspect reed valves for failure. Seems the biggest controversy is over using a light to inspect the reed valves. Some say light passing through the reed is unacceptable while others say it is not. One said he checked a brand new reed valve assembly and saw no light passing through while others said a small amount of light is normal on new and used assemblies.
Seems to be fairly good agreement about diagnosing a failed reed valve. If the carburetor is spitting fuel back out the bore or other port then chances are you have a reed valve problem. Carburetor spitting is not to be confused with carburetor bowl flooding or overflow. A very small, essentially imperceptible amount of fuel coming back out the bore is normal but the spitting I am talking about is quite noticeable if you are looking for it.
The Evinrude factory service manual I am using for my 1984 40HP two cylinder simply calls for a visual inspection of the reed and seat. Look for broken or chipped reed or damage to the seat. They show some photos but only gross failures shown in the photos.
My experience with a failed reed valve assembly was a learning experience. I had carburetor spitting and I was sure it was abnormal. I also had a bit of an idle problem. I wasn?t sure if the two were related but I was sure the spitting was not normal. I was also pretty sure there were no carburetor float or fuel level problems in the carburetor bowl because I had just rebuilt the carbs and replaced needle, seat and float. Also carefully adjusted float level. I was ready to pull the reed valve assembly so that is what I did. First thing I did to the assembly was a visual inspection with the naked eye. Looked at reed and seat and they looked good. Next I did the light test. Several reeds had light passing through and I thought I had found the problem. On this engine OMC/Bombardier only sells the whole reed valve assembly so I purchased the two assemblies required. Guess what I did as soon as I got the new assemblies. Several reeds were passing light on the brand new assembly. Still fairly convinced that I had a reed valve problem on the old assembly I decided to disassemble the old reed valve assembly for more inspection. Still looked good after disassembly. Next I decided to take a closer look at the seat with a magnifying glass. Found it. At least two seats were damaged and/or worn. Most looked like new but I could see the difference on the worn/damaged seats. Installed the new reed valve assemblies and fired it up. Idle was smooth and no more carburetor spitting. Problem solved.
My conclusion is that the passing light test is not a conclusive test and probably not worth doing. The visual inspection is probably the best way but it sure would be helpful if the factory service manual gave more detail on how to do the inspection. Optic magnification is definitely required. A low power microscope would be ideal but the magnifying glass seemed to work. Hope this helps with diagnosing and inspecting reed valves.
Seems to be fairly good agreement about diagnosing a failed reed valve. If the carburetor is spitting fuel back out the bore or other port then chances are you have a reed valve problem. Carburetor spitting is not to be confused with carburetor bowl flooding or overflow. A very small, essentially imperceptible amount of fuel coming back out the bore is normal but the spitting I am talking about is quite noticeable if you are looking for it.
The Evinrude factory service manual I am using for my 1984 40HP two cylinder simply calls for a visual inspection of the reed and seat. Look for broken or chipped reed or damage to the seat. They show some photos but only gross failures shown in the photos.
My experience with a failed reed valve assembly was a learning experience. I had carburetor spitting and I was sure it was abnormal. I also had a bit of an idle problem. I wasn?t sure if the two were related but I was sure the spitting was not normal. I was also pretty sure there were no carburetor float or fuel level problems in the carburetor bowl because I had just rebuilt the carbs and replaced needle, seat and float. Also carefully adjusted float level. I was ready to pull the reed valve assembly so that is what I did. First thing I did to the assembly was a visual inspection with the naked eye. Looked at reed and seat and they looked good. Next I did the light test. Several reeds had light passing through and I thought I had found the problem. On this engine OMC/Bombardier only sells the whole reed valve assembly so I purchased the two assemblies required. Guess what I did as soon as I got the new assemblies. Several reeds were passing light on the brand new assembly. Still fairly convinced that I had a reed valve problem on the old assembly I decided to disassemble the old reed valve assembly for more inspection. Still looked good after disassembly. Next I decided to take a closer look at the seat with a magnifying glass. Found it. At least two seats were damaged and/or worn. Most looked like new but I could see the difference on the worn/damaged seats. Installed the new reed valve assemblies and fired it up. Idle was smooth and no more carburetor spitting. Problem solved.
My conclusion is that the passing light test is not a conclusive test and probably not worth doing. The visual inspection is probably the best way but it sure would be helpful if the factory service manual gave more detail on how to do the inspection. Optic magnification is definitely required. A low power microscope would be ideal but the magnifying glass seemed to work. Hope this helps with diagnosing and inspecting reed valves.