How To Change Fuel Filter On A 8 Hp Mercury Outboard Motor

The Mercury 25 HP 4 stroke outboard motor model delivers constant easy starting, crisp throttle response, maximized fuel economic system, and overall outstanding performance.

Though this advanced, compact Mercury outboard motor offers EFI that no other outboard or boat manufacturer offers at this horsepower rating, oftentimes users experience some troubleshooting issues while using it.

In this article, I will reveal the nearly common problems that may occur with the Mercury 25 HP 4 stroke outboard motor and allow y'all know how to deal with those bug.

Problems	Reasons
Outboard Idles Roughly Or Stalls	Low force per unit area on the fuel pumpFuel tank air vent is airtight or restrictedDamaged or restricted fuel lines and fuel filters
Outboard May Hesitates Upon Acceleration	Ignition organisation has no spark or even weak or low sparkIf the Carburetor is overflooded
Motor May Feel Sputtering Or Powe Loss Issues	Bad fuel condition

i. Outboard Idles Roughly Or Stalls:

Co-ordinate to Mercury 25 HP iv stroke many users, sometimes the motor idles rough or stalls.

Users claimed that the outboard motor runs irregularly or unevenly while they put information technology neutral or out of gear.

However, various reasons may crusade this particular commotion, but first, you need to practise the proper investigation.

Possible Fix

It may occur when your fuel pump has depression pressure, and then you demand to perform a test to inspect the fuel pump and fix the trouble.

Earlier performing the test, make sure to read the repair service provided with your outboard. The manual will guide y'all to select authentic specs and larn the exact procedures to follow to fix your fuel pump's issue.

First, start the fuel pump testing by turning off the outboard engine's power. Then, disconnect and remove the cowl cover, the plug, spark plug wire kick.

At present, you lot should check the compression gauge reading, and if the gauge reading shows less or above xxx PSI, the compression gauge needs to supersede. The fuel pump gets afflicted by the damaged diaphragm or one-mode valves so, cheque them and supercede the faulty function.

The problem can besides occur if the fuel tank air vent is closed or restricted.

Therefore, check and inspect the air vent located on the fuel tank. If information technology is not open, plow it on the open up position. Remember, the fuel tank air vent should ever stay open and complimentary from friction.

Some other possible reason behind this problem tin be the damaged or restricted fuel lines and fuel filters.

Therefore, inspect all the fuel lines for whatever clogged or impairment problems and also bank check whether any fuel line connection is loose or non. If y'all notice loose connections, tighten them accordingly. Just do non overtighten any connections. If the fuel lines are clogged or severely damaged, y'all should clean or replace the damaged fuel lines.

While inspecting the fuel filter, if information technology is broken or restricted because of excessive corrosion or other contaminates, either you should clean or replace the fuel filter with a new one.

2. Outboard May Hesitates Upon Acceleration:

Another common problem that Mercury 25HP four-stroke outboard users oft complain about is the motor'southward visible hesitation on dispatch.

Sometimes, they notice that the outboard motor struggles or hesitates when they put on the acceleration, and even the engine starts to run unevenly or surges.

Several reasons tin pb to this particular commotion since these types of problems are interconnected,

So, let'due south discover out what are the possible reasons and how to handle those.

Possible Fix

When your ignition organization has no spark or even weak or depression spark, your outboard motor volition hesitate or run unevenly.

To verify whether the main culprit is the ignition organisation, use a spark tester or detector to test the spark. You can get the spark tester or detector from any auto supplies or parts stores, and you lot do not demand any specific blazon of spark tester for the Mercury 25 HP four-stroke.

Now, you need to ready 3/eight inches gap on the spark detector and creepo your motor to investigate the spark condition of each motor cylinder. If you see the spark in both cylinders, that means your ignition organization is okay.

But if you encounter no or poor spark on i or both cylinders, you demand to audit the yellow and black wires. Use the tester on both wires, and if yous cannot meet whatsoever spark, you need to replace the wires.

In that case, remove the wire from the switch box and supercede information technology.

Another possible reason can be the carburetor as well…

At present, test the spark condition on the carburetor with the same spark tester and follow the same method. If you see no spark in there and found an excessive corporeality of viscid gunk insider of the carburetor, that means your carburetor is overflowed with the gunk and preventing closing the valves.

First, you lot need to drain the old, dirty fuel by removing the fuel cap. And so, yous need to remove and dip the carburetor in a carburetor-cleaning solution to clean the carburetor.

But remember, no need to remove the primary jet from the carburetor while soaking it in the solution. Wait and let it soak in the solution for a minimum of an 60 minutes. After that, you tin can remove the jet from the carburetor.

Apply a flathead screwdriver to eject the main jet from the carburetor and remove the main jet. Now, rinse and dip the fuel jet, just similar the carburetor. And then, spray compressed air on the fuel jet to remove the excess gunk and clear the path for the fuel flow.

If the jet seems damaged, replace it with a new one and put it back inside the carburetor.

3. Motor May Experience Sputtering Or Powe Loss Issues:

Some of the Mercury 25 HP 4 stroke motor users have complained that the motor sometimes sputters or constantly loses more power than usual.

This particular issue occurs when they have out their outboard to utilize subsequently several months of not using.

However, to fix the result permanently, you demand to empathize what is causing this sudden commotion. So, let'due south find out the reason and solution.

Possible Gear up

Well-nigh outboard motors usually experience this issue for the bad fuel condition.

If your motor uses ethanol-blended fuel mix or fifty-fifty x% ethanol in the fuel mix, this problem can arise. But you can easily avoid this commotion past using the Mercury recommended fuel mix.

Mercury recommends using either unleaded Regular 87 Octane Minimum (R+Chiliad/2) or 90 RON 10% Ethanol Maximum for all their outboard motor and especially, for the 25HP 4 stroke one.

Notwithstanding, sometimes consumers practise not clean or change the fuel regularly or before every use, which leads the fuel to turn muddy or bad. That's when your engine will outset to lose ability.

You tin can too prevent the problem past using a high-quality 10-micron fuel and water separating filter. This high-quality filter will keep water out of your outboard motor and fuel.

Too, use a high-quality fuel stabilizer whenever you add new and fresh fuel into the fuel tank.

What The Bulk of Users Experience About the Mercury 25 HP iv Stroke?

The bulk of the Mercury 25HP 4-stroke users are satisfied with the overall performance, and the motor performs excellently in shallow or even in absurd water. Some users likewise mentioned that this compact electrical motor is faster and torquey than other competitor'due south motors.

However, it is undeniable that some common issues arise while using this outboard motor, and users have already confirmed that. Merely fortunately, none of those problems are severe and hands fixable.

Final Thoughts

The Mercury 25 HP four stroke outboard motors characteristic an advanced technology that made them easy to install and operate. These compact outboard motors come up with reliable starting, depression vibration, and quick acceleration to perform with exhilarating speed.

Withal, just like other Mercury outboard motor lineup models, the Mercury 25 HP 4 stroke outboard motors are non entirely faultless, and users should exist well aware of those problems.

Related Posts:

3 Virtually Common Bug With 3.0 MerCruiser
Most Mutual Problems with Suzuki DF140
7 Most Common Problems With Mercury Verado 350
Most Common Issues with Mercury Pro XS 150
3 Nigh Common Problems with Suzuki 350 Outboard