What Is The Johnson Outboard Fuel Line Size: Why Does The Fuel Line Size Matter?
Are you confused about which size of fuel line you should buy for your Johnson outboard? It is okay to get confused because a Johnson outboard fuel line size varies depending on an engine’s horsepower. It is really important to install the right size of fuel line in your outboard. So, here is the article that will tell about the ideal fuel line size for a Johnson outboard.
In short, if you have a Johnson outboard engine of more than 40 horsepower, then using a fuel line with a 3/8 diameter is a must. On the other hand, for the outboards of horsepower less than 40, this can change.
Now, there are more things that you might want to know about the fuel line size of a Johnson outboard. For your convenience, we explained the fuel line size in-depth.
The Size Chart Of Johnson Outboard Fuel Line Size
The chart below will give you a clear understanding of the Johnson Outboard Fuel Line Size–
Horsepower Of The Engine | 40 or more | Less than 40 |
Fuel Line Size | 3/8 diameter | 5/16 diameter |
The Reason Why The Fuel Line Size Matters
Some people are not much serious about the size of the fuel line of their outboards. They think any size would fit perfectly. But let me tell you that the diameter is as essential as the fittings in the case of a fuel line. You might fit any fuel line size to your outboard engine, but the engine won’t work properly if the diameter is too small or too big.
Below are the problems that arise due to using the wrong size of fuel line-
Problems Of Using Smaller Fuel Lines
You already know that you must use a fuel line of 3/8 diameter if your outboard engine has 40 horsepower or more than that. But why is that so? Do you know what will happen if you use a fuel line size of 5/16 diameter in a greater horsepower engine? If you do not know, have no worries! I am here to solve all your queries.
Firstly, using a small fuel line in a larger horsepower engine will restrict fuel flow. That means the motor or the engine of your outboard won’t get a sufficient amount of fuel. Remember, the larger fuel line diameter means a higher fuel flow, and an engine with high horsepower requires more fuel flow.
Next, the restriction on the flow of fuel due to the smaller size of the fuel line is dangerous. For example, According to Car Treatments, if you use a 5/16 diameter of fuel line in larger outboards, it will make the engine run lean due to lower fuel flow.
Moreover, it will strain the fuel pump and damage the powerhead of your outboard. This damage to the powerhead can lead to an engine blow-up.
Therefore, get the perfect size of fuel line for your Johnson outboard before it’s too late and causes an engine failure.
Problems Of Using A Bigger Fuel Line
Now, you might think that using a 3/8 diameter fuel line in an outboard of less than 40 horsepower won’t create any problems. If you really have this idea, you are wrong. Let me tell you why.
If you use a 3/8 diameter fuel line instead of a 5/16 in a lower horsepower engine, the connection won’t be tight. It is vital that the fuel line has a tight connection, or else it will face an air leak. This air leak from the fuel line will make the engine lose its prime.
Frequently Asked Questions (FAQs)
A marine fuel line is totally different from an auto fuel line. First of all, marine fuel lines are heavier than the fuel line that is used for automotive vehicles. Next, the fuel line of marine grade has a higher fire testing rate. That means the fuel lines of outboards must have a fire test rating of 2.5 minutes.
The working pressure of a 3/8 fuel line is 300 PSI (Pound Per Square Inch).
Final Words
Hopefully, you have got a clear understanding of Johnson outboard fuel line size. Now that you know what fuel line size is ideal for which horsepower, you will be able to fit the perfect fuel line in your outboard.
Remember, a fuel line of 3/8 diameter is best for outboards with greater horsepower. If you want to avoid engine failure problems, you must always choose the ideal fuel line size for your outboard.
I hope that this article was a great help to you. Have a great boating!
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