Are you using the same fuel filter on your boat for a long time and worried about its condition? Is it OK to use a boat fuel filter for extended periods without replacing it? How often should a boat fuel filter need to be replaced?
As a general rule, experts suggest replacing a boat fuel filter every 100 hours regardless of its condition. Yet, inspect it before every season, look for corrosion in/on it, vacuum gauge values (if any), and, most importantly, replace it if the boat engine is sputtering or decreasing performance.
Many people may advise you to replace it yearly for a piece of mind. But, as always, inspect it annually, look for corrosion on it, bad fuel color inside the filter, vacuum gauge values (if any), if the boat engine is sputtering, and replace on condition. If none are there, you can use it for some more time.
The fuel filter is in place to protect your boat engine from receiving any impurities that may have made it into fuel. But like any other type of filter, it will eventually clog up with the materials it is filtering out. And using the boat often requires you to change the filter often due to more filtering.
Since the boat’s fuel filter plays a crucial role in keeping the boat engine working and not surging at high speeds or not stopping while running, many recommend replacing it yearly regardless of its condition, so that you need not worry about the engine failure due to fuel filter failure in the middle of the lake.
Tip – If you are thinking of replacing your boat fuel filter yearly regardless of its condition, keep the old one as a spare in your boat. You can use the old one during an emergency. Throughout the post, we will see about the primary fuel filter, not the secondary one.
Most boats will have two fuel filters installed; the primary fuel filter is larger and separate from the engine (that’s what many will refer to as “change the fuel filter”), while the secondary fuel filter is smaller mounted on the engine.
It also depends on the number of hours used and above all what kind of fuel you use in the boat, i.e., ethanol fuel or ethanol-free fuel. Even if the fuel contains more impurities, the filter may quickly plug with those impurities, and as a result, the engine sputter or won’t start.
As mentioned earlier, you can replace it whenever you see corrosion in/on it or bad fuel color inside it or if the engine is sputtering. But if you don’t want to take the risk (of engine failure in the middle of the lake), you can replace it yearly or follow the manual and replace it after using it for that many hours.
Before going into the technical essence related to the fuel filters, take a look at this small video on the fuel filter working if you aren’t familiar with it’s working.
When to replace the boat fuel filter? 4 bad symptoms to look for
We will now see the symptoms that a bad boat fuel filter will show. However, it would be best if you verify those bad symptoms before replacing the fuel filter.
If the engine is sputtering often
One of the most common causes for a boat engine to sputter while starting is due to the issue with the fuel system; it can be a filter, pump, and injectors. These three vital components work together to ensure fuel flows smoothly from the fuel tank to your engine.
If anything interrupts the fuel flow or if anything other than fuel gets into the engine (like water or contaminated fuel), the boat engine will surge or stop while running. So, it is crucial to filter all the dirt that comes along with the fuel, and it can be water or any debris.
Ensure whether the fuel is being contaminated or not before immediately replacing the fuel filter. If the fuel inside the filter doesn’t look good, replace it. Otherwise, look for any leaks along the lines or any. Still, if you didn’t find anything, go near the mechanic.
Poor engine performance
As mentioned earlier, a bad fuel system can cause engine sputtering. In the same way, it can also decrease the engine’s performance. Under heavy loads, a plugged fuel filter may randomly cause the engine to hesitate, surge, or sputter. You could see it under normal loads if the blockage is severe.
That hesitate, surge, or sputter tends to be more prominent when accelerating, especially in the rough waters. Although there may be no symptoms under normal conditions in calm water, a clogged fuel filter will starve the engine of the extra fuel needed when quickly accelerating.
Depending on the extent of the fuel restriction caused by a lousy fuel filter, a boat engine may also shake or stutter at different speeds. So, you won’t get as much power as you used to get if the engine is getting bad gas or something else other than gas into it. If you see those signs, replace your fuel filter.
Increased vacuum gauge values
If you have a vacuum gauge or any that tells the fuel flow, you can know right away that something is restricting the fuel flow around the primary fuel filter. Nowadays, few fuel filters are getting small gauges on them at a price 3 or 4 times greater than normal ones.
Otherwise, you can install vacuum gauges on the output side of the primary fuel filter before the pump, which will show an increase in the vacuum when the primary filter is restricting the flow of the fuel, indicating the filter element in the primary filter needs to be changed (source).
So, if you have them, you will get to know right away that something is slowing down the fuel flow around the primary fuel filter. And that something could be small trash blocking the fuel to pass through the filter paper, slowing down the whole filtering process.
Corrosion in/on the fuel filter
Rust could be a big problem inside the fuel filter; even if it is a brand new fuel filter, rust can form inside it if you use gas with more percentage of ethanol (water) in it. Since ethanol is hygroscopic, you can have these problems if moist air can get to it. Corrosion can happen outside, on the filter as well.
If you see any signs of that, better replace the fuel filter and siphon the rest of the fuel out of the boat and, also cleaning all the fuel lines could be a better practice. After getting a new fuel filter, fill it up, go for a ride, and check if you are still having the issue. If yes, there is some other problem other than the fuel filter.
Also, look for the fuel color inside the fuel filter by poring it in any transparent container or glass. If you see a color other than the color of the fuel or if you smell anything other than the smell of the fuel, it’s time to replace the fuel filter on your boat.
How to get the most out of your boat fuel filter?
As always, maintenance plays a crucial role in getting most of anything. If the fuel filter is taken proper care of by following the steps below, you can last one for a long time. However, it also depends on the number of hours used and above all what kind of fuel is used.
Use ethanol-free gas if possible. The gas used plays a crucial role in deciding the life of the fuel filter. If the fuel contains more impurities or more water %, the filter may quickly plug with those impurities or corrodes due to more water, and as a result, the engine sputter or won’t start.
It is also recommended not to go above E10 gas. Better go for non-ethanol gas, fill it up at the marina or elsewhere. However, the prices could be a bit higher in the marina than in other places so look at the prices.
Use dedicated filters for each engine. If you are running 2 or more engines through 1 filter, you are going to have a restriction. Restrictions mean the motors will both run lean. If they run lean enough, they will blow. And it also prevents or helps from contaminating both engines in case of debris or water in a tank.
Buy a fuel filter that has a clear bowl below. That way, you can look for the water from time to time and drain them if more water is present (they’ll have a valve to drain water from the bottom without removing the filter), allowing us to monitor our fuel condition much better. However, these variants are a bit expensive than normal ones.
Make your fuel system as closely as possible. If your boat is exposed to humidity being stored outside, the fuel system can get air. Moisture can form inside the fuel system if the air gets inside, causing corrosion inside and outside the fuel filter, causing other problems as well.
The fuel filter is in place to protect your boat engine from receiving any impurities that may have made it into fuel. But like any other type of filter, it will eventually clog up with the materials it is filtering out. And using the boat often requires you to change the filter often due to more filtering.
Key takeaways
A boat fuel filter needs to be replaced if you see corrosion in/on it or vacuum gauge values are high (if any), or most importantly, if the boat engine is sputtering or decrease in performance. As a general rule, experts advise replacing a boat fuel filter every 100 hours for peace of mind.
Using your boat more often requires you to change it often since a fuel filter is in place to protect your boat engine from receiving any impurities that may have made it into gasoline. But like any other type of filter, it will eventually clog up with the materials it is filtering out.
Using ethanol-free gas will make a huge difference, and it will definitely increase your filter life. So, avoid ethanol fuel if possible. Also, look at the fuel color inside the filter by pouring it in a jar; if it looks & smells good, you can use the filter for some more time.
