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Honda BF20D cutting out

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Forancomp

New member
Hi
I have a problem with my Honda 20hp outboard. It starts and idles for approx 3 min and then dies. It might start again and dies again. If I get it to start again and back and forth with the throttle to get it to some revs and if I let it go to idle it dies again. Vent in tank is open. Tried with cap off tank. Cleaned out tank completely changed fuel filter. Opened screw in carb to see petroleum running New plugs fitted. I’ve run out of ideas at this stage. Any help would be very much appreciated
 
I would likely pull the carb and clean.... you will likely see the cause in the bowl... it runs while cold enrichment is adding extra fuel for first minutes on intial startup.
 
Thanks for that I’ll have a look at bowl in carb tomorrow Even though the old fuel filter didn’t look that bad when I changed it do you think some gunge may still have got through?
 
Nothing may have gotten thru... could just old fuel ... it will leave deposits.... the aluminum float bowl will turn green as it comes in contact with old fuel and moisture
 
Hi,

This sounds very much like it could be a bad "bystarter" valve. Also known as the
Service Enrichment (SE) valve.

The SE valve is what is used to richen up the mixture for cold starting on these carburetors. It replaces the older, conventional "butterfly" type choke system for getting the engine started when cold.

It is mounted to the top of the top carb and has two wires going to it because it is electrical.

The valve allows extra fuel to the engine when cold. After the engine starts, 12 volts from a coil under the flywheel causes the valve to heat up and extend to shut off the extra fuel and keeps it turned off to keep the mixture from being too rich. The heating up of the valve takes
2 1/2 to 3 minutes and it remains hot while the engine is running

If the valve is stuck and doesn't work OR, if it doesn't get the 12 volts it needs to get hot and shut off the extra fuel, the fuel mix will be too rich and the engine is likely to stop running as a result. This sounds like the symptoms you describe.

You can test the valve and check for the voltage from the coil without removing the carburetors. I would do that before trying anything else in this case.

The procedure for testing is in the workshop manual if you have one.
 
See it lots after coming out of storage... make sure all circuit's get a complete cleaning .... the carbs at pretty simple carbs.
Run something thru all orifices.... some are pretty small .... I use a single stand off bicycle brake cable for idle circuit.... make sure o rings are good.
 
jgmo said:
Hi,

This sounds very much like it could be a bad "bystarter" valve. Also known as the
Service Enrichment (SE) valve.

The SE valve is what is used to richen up the mixture for cold starting on these carburetors. It replaces the older, conventional "butterfly" type choke system for getting the engine started when cold.

It is mounted to the top of the top carb and has two wires going to it because it is electrical.

The valve allows extra fuel to the engine when cold. After the engine starts, 12 volts from a coil under the flywheel causes the valve to heat up and extend to shut off the extra fuel and keeps it turned off to keep the mixture from being too rich. The heating up of the valve takes
2 1/2 to 3 minutes and it remains hot while the engine is running

If the valve is stuck and doesn't work OR, if it doesn't get the 12 volts it needs to get hot and shut off the extra fuel, the fuel mix will be too rich and the engine is likely to stop running as a result. This sounds like the symptoms you describe.

You can test the valve and check for the voltage from the coil without removing the carburetors. I would do that before trying anything else in this case.

The procedure for testing is in the workshop manual if you have one.
Click to expand...

jgmo said:
Hi,

This sounds very much like it could be a bad "bystarter" valve. Also known as the
Service Enrichment (SE) valve.

The SE valve is what is used to richen up the mixture for cold starting on these carburetors. It replaces the older, conventional "butterfly" type choke system for getting the engine started when cold.

It is mounted to the top of the top carb and has two wires going to it because it is electrical.

The valve allows extra fuel to the engine when cold. After the engine starts, 12 volts from a coil under the flywheel causes the valve to heat up and extend to shut off the extra fuel and keeps it turned off to keep the mixture from being too rich. The heating up of the valve takes
2 1/2 to 3 minutes and it remains hot while the engine is running

If the valve is stuck and doesn't work OR, if it doesn't get the 12 volts it needs to get hot and shut off the extra fuel, the fuel mix will be too rich and the engine is likely to stop running as a result. This sounds like the symptoms you describe.

You can test the valve and check for the voltage from the coil without removing the carburetors. I would do that before trying anything else in this case.

The procedure for testing is in the workshop manual if you have one.
Click to expand...
I’ll have to look into this a bit further se valve is new to me Thanks 👍
 
siscoken said:
See it lots after coming out of storage... make sure all circuit's get a complete cleaning .... the carbs at pretty simple carbs.
Run something thru all orifices.... some are pretty small .... I use a single stand off bicycle brake cable for idle circuit.... make sure o rings are good.
Click to expand...
I’ll have to think about touching the carb
 
jgmo said:
Hi,

This sounds very much like it could be a bad "bystarter" valve. Also known as the
Service Enrichment (SE) valve.

The SE valve is what is used to richen up the mixture for cold starting on these carburetors. It replaces the older, conventional "butterfly" type choke system for getting the engine started when cold.

It is mounted to the top of the top carb and has two wires going to it because it is electrical.

The valve allows extra fuel to the engine when cold. After the engine starts, 12 volts from a coil under the flywheel causes the valve to heat up and extend to shut off the extra fuel and keeps it turned off to keep the mixture from being too rich. The heating up of the valve takes
2 1/2 to 3 minutes and it remains hot while the engine is running

If the valve is stuck and doesn't work OR, if it doesn't get the 12 volts it needs to get hot and shut off the extra fuel, the fuel mix will be too rich and the engine is likely to stop running as a result. This sounds like the symptoms you describe.

You can test the valve and check for the voltage from the coil without removing the carburetors. I would do that before trying anything else in this case.

The procedure for testing is in the workshop manual if you have one.
Click to expand...
I think you might be right I got the manual and will test
 
This is just an update on my boat I reckoned if the SE valve was faulty and I would have a rich mixture. The spark plugs would be sooty and blackened but they looked okay so I installed new fuel lines and a new primer bulb while it started, It wouldn’t idle. So I thought to myself, I will clean the carb and set about removing the carb carefully and sprayed the Jets with carb cleaner and a gentle air blower. Put it all back together and hey Presto she is purring like a cat. She rev’s quickly and she will also tick over to an idle speed. Thanks for all the Advice. 👍
 
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