Mercury Pro XS 150 Problems and Solutions: Things You Need To know

Modern outboard motors have come a long way with the four-stroke engines. Reliability is much better than in previous decades, fuel economy has improved, and issues such as smoke emissions and loud noise levels are a thing of the past. Even some typical Mercury Pro XS 150 problems come up repeatedly.

To get the best out of the Mercury pro, you have to solve the problems. Today, we will talk about the issues and their solutions. So, here we go!

Mercury Pro XS 150 Problems and Solutions

Though some people say that the problem of the outboards is hard to solve, we’ve got some easy solutions for them. Let’s find them.

Problem1# Motor Problems

A new user complained only twice after running the Pro XS 150 failed to trim perfectly. When he slowed down and finished trimming the motor up before giving gas, the motor trimmed itself back down. I didn’t have enough information to pinpoint the exact cause of the problem. Perhaps your dealer knows about it.

Mercury Pro XS 150 Problems and Solutions
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Taking the motor to warranty and not touching it under any circumstances is the best option.

We can, however, assume that the trim is working correctly. You may notice that the problem has vanished after correctly following the break-in procedure.

The manufacturer recommends that everyone run the new 150HP 4-stroke engine at various throttle settings for the first two hours. You can reach 4500 RPMs by combining the low and high RPM settings. Alternatively, you could say 3/4th throttle.

After that, for the next 8 hours, run the motor at its highest RPM setting for about 1 minute at 10-minute intervals. You must not, under any circumstances, run the engine at full throttle for more than 5 minutes at a time. Also, you must ensure that your dealer has installed the correct battery size.

Problem 2# Coil Problems

The issue is as follows: A user reported that his Pro XS 150 couldn’t go faster than 4900 RPM and 49 mph. However, one of the mercury outboard bad coils could be the source of the problem.

I’m not implying that the individual’s assumption is incorrect. Because a faulty coil produces no spark, the cylinders will misfire.


You must take the engine to the dealer if the warranty period has not expired. Otherwise, contact a mechanic to have the bad coil replaced. You can now test the coil yourself instead of paying a boat mechanic. Unplug the wires from the coil end or the battery end. Remove the spark plug as well.

Measure the resistance in the wire with a multimeter or an ohm-meter. Connect one meter probe to the positive terminal and the other to the negative terminal. Set the dial to 200 and check to see if the value is between 0.02 and 0.04.

The primary circuit’s test results are now available, and it’s time to look at the secondary circuit. Connect the negative terminal to the red probe and the coil tower. The reading should now be between 8 and 11 points.

Problem 3# Engine not Starting

As many quick-disconnect attachments that connect the fuel tube to your outboard are plain cheap, this happens frequently. The tips that connect the fuel line and fitting and the tube clamps that attach them are the same.

These associations tend to leak or permit air to suck in over time. Cheap hose clamps, fuel lines, and connectors are common causes of outboard engine problems.


Squeeze your ball while keeping an eye on the engine-to-line fitting, the barb-to-hose fitting, the tip on each end of this ball if visible, and the line-to-tank fitting. The leak must be identified and contained.

Press the ball repeatedly while listening for a gurgle next to the connection if there’s no visible fuel leak. After isolating the leak, you can repair it by trimming a fuel line section, reattaching the tip, fitting it with a new hose, or simply changing a hose clamp.

You can push the fitting to one end and other to get your engine running again if it has gone wrong. Once you’ve done that, the engine’s draw is enough to maintain the fuel flowing.

Problem 4# Engine Cranks But Never Attempts To Catch

This could be for various reasons (first, make sure the shifter is neutral), but your emergency cut-off switch is probably wrong if it doesn’t even try to catch. It appears as if the lanyard clip has been removed, preventing the engine from starting. This is a widespread and annoying problem if the switch is mounted horizontally in a location where water can pool on it and cause damage.


You must turn off the emergency kill switch. Examine the wiring at the back of the switch panel. The black one with the yellow stripe is what you’re looking for. Disconnect it and try the key again; the engine will start right up.

Problem 5# Tangled Propeller

A tangle could cause your outboard motor’s inability to throttle. You can wrap the propeller, and its spindle in fishing lines, too much seaweed, beer may ring, and almost any other materials.

These materials cause the bog, which prevents the propeller from rotating and propelling the boat into the water. Also, you may notice the engine vibrating significantly, which signifies that you must replace the propeller.


Tangled propellers are a common problem, particularly for people boating in crowded areas or shallow water. Terminate anything that you might wrap around your propeller first.

After removing the item, inspect it for any damage. If your propeller is bent or cracked, it must be replaced with an exact match.

Problem 6# Clogged Fuel Filter

A clogged fuel filter is another common cause of your engine bogging down when applying throttle. The primary purpose of the fuel filter is to strain out any debris and dirt that may enter the engine, but if there is enough debris, the fuel filter can become blocked.

This incident may not be a problem during startup or idle, but as you throttle down and draw in more gasoline, the pressure may cause the debris to block the inlet. As a result, the fuel pump has to work harder, putting strain on your engine.


If you notice the plastic covering on your fuel filter degrading and darkening over time, you know it’s the source of your outboard bog. The fuel filter becomes brittle over time and may leak gasoline. Because gasoline can deteriorate the plastic of your fuel filter, it’s critical to drain the engine of gas between seasons to keep your outboard motor in good working order.

Begin by looking at the fuel filter. Carefully remove the fuel filter cover with gloves and a small container to catch any spilled gas.

You might notice accumulated particles inside, indicating what kind of material is getting into your fuel lines. The interior liner of fuel hoses frequently degrades, breaking into tiny chunks that the fuel filter catches.

Problem 7# Malfunctioning Fuel Pump

The fuel pump is in charge of delivering gas from your fuel tank to your engine. You may notice the outboard bogging down when you throttle up or idle if it isn’t operating correctly.


Remove the plug wire from your spark plug and perform an outboard fuel pump test. With a wrench and plug socket, remove the spark plug. In the plug socket, place a compression gauge.

You’ll probably need someone to start it while you twist the throttle open if you’re using an electric motor. With a pull motor, you can open the throttle with one hand while pulling the rope start with the other.

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