Generator fuel selector

[Roddono]

Hello all. Would love some feedback on the following situation. My 1991 Carver 33’s Koehler genny will run all day long when the fuel selector switch is set to starboard fuel tank. If I select port fuel tank it will run for 20 minutes almost exactly. Both fuel tanks have about a half tank of new good fuel in them. Engines perfect. Am I missing something? Is there something I am doing wrong?

Thanks in advance.

Ray

[km1125]

Can you restart it n the port fuel tank, or do you need to switch back to the starboard tank to run it?

I'm wondering if you have a bad anti-siphon valve on that port side, or an air leak that prevents you from pulling from the port side. Could the 20 minutes be just what the generator uses in the lines and the filter?

[Roddono]

Km1125,

I have to switch back to starboard to start. Then when I switch it back to port I get approximately 20 minutes. My thinking is that as well, maybe that is the amount of fuel in the line now. That seems like an excessive run though. I have also read I might have a bad pick up line in the port tank.

What is an anti-siphon valve and how do I check it? I know dumb question.

Thanks. Ray...

[Viper]

Ya looks like it's something related to that tank or delivery system on that side. You don't know what the previous owner did so ensure that the fuel line to that tank from the selector valve is actually hooked up at the valve and not blocked off at the valve or tank. The option may also have been available but not installed. Also check the line and ensure there are no kinks anywhere to that tank. Could you be pointing the valve the wrong way? I've seen this before! Could also be a faulty valve.

The anti-siphon valve is a fitting on top of the tank and is what the fuel line is connected to. There is a ball and spring in it so you can't see through it. Could be a straight fitting or an elbow. Remove it and try running the genny again. If it continues to run normally, you likely found your problem but you must replace the anti-siphon valve with a new one as it is a safety device. You can try cleaning the valve and reusing it but why bother reinstalling a 30 year old $15 part.

Here is an example: https://www.defender.com/product.jsp?id=2685649

[Roddono]

Qr Bbpost Ya looks like it's something related to that tank or delivery system on that side. You don't know what the previous owner did so ensure that the fuel line to that tank from the selector valve is actually hooked up at the valve and not blocked off at the valve or tank. The option may also have been available but not installed. Also check the line and ensure there are no kinks anywhere to that tank. Could you be pointing the valve the wrong way? I've seen this before! Could also be a faulty valve.

The anti-siphon valve is a fitting on top of the tank and is what the fuel line is connected to. There is a ball and spring in it so you can't see through it. Could be a straight fitting or an elbow. Remove it and try running the genny again. If it continues to run normally, you likely found your problem but you must replace the anti-siphon valve with a new one as it is a safety device. You can try cleaning the valve and reusing it but why bother reinstalling a 30 year old $15 part.

Here is an example: https://www.defender.com/product.jsp?id=2685649

Viper, thanks for that info. I will check above suggestions. Will the tanks have one or two individual anti-siphone valves? Reason I ask is that the port engine runs perfect.

Thanks.

Ray

[Viper]

If installed properly, each plant; engine and genny, will have their own separate/dedicated pickup and anti-siphon valve.

[bud37]

Qr Bbpost Hello all. Would love some feedback on the following situation. My 1991 Carver 33’s Koehler genny will run all day long when the fuel selector switch is set to starboard fuel tank. If I select port fuel tank it will run for 20 minutes almost exactly. Both fuel tanks have about a half tank of new good fuel in them. Engines perfect. Am I missing something? Is there something I am doing wrong?

Thanks in advance.

Ray

Just to add to all the above good info.....can you take a pic of the selector switch with it in the position you know works and post it.....that may help the visual.

[Roddono]

Qr Bbpost

Qr Bbpost Hello all. Would love some feedback on the following situation. My 1991 Carver 33’s Koehler genny will run all day long when the fuel selector switch is set to starboard fuel tank. If I select port fuel tank it will run for 20 minutes almost exactly. Both fuel tanks have about a half tank of new good fuel in them. Engines perfect. Am I missing something? Is there something I am doing wrong?

Thanks in advance.

Ray

Just to add to all the above good info.....can you take a pic of the selector switch with it in the position you know works and post it.....that may help the visual.

I will do that later today. Thank you.

Ray

[buster53]

I had issues with my genset last year. Turned out I happened to have 2 separate problems. My repair guy determined my fuel pump was bad...replaced it and the engine would run, not good, but did run. After talking through our problems, we decided the anti siphon valve might be bad. Replaced it and all was good.