Most Common Problems with Mercury Pro XS 150

For bass, offshore fishing, and runabout boats, Mercury Pro XS 150 has been a trusted product for a long time.

Considering the price, build quality, and performance, it surpasses its closest competitors. Nonetheless, the motor has some issues like other products in the market.

In this article, I am going to talk about the 4 most common problems with Mercury Pro XS 150 and try to give you possible solutions. 

ProblemsReasons
Motor stuck at low trimNot identified
Bad or faulty coil giving trouble starting the engineCan go wrong after a certain timeFaults at production
Engine not starting at allMore ethanol in the fuel than recommendedLeaving the ethanol-mixed fuel for too long in the tank
Problems while claiming warrantyCustomer not complying with the warranty conditions

1. Motor Problems

A new user running the Pro XS 150 only twice complained that the motor did not trim past almost one-fourth of the trim at 30 or 31 miles per hour.

Once he had slowed down and finished trimming the motor up and gave gas, the motor trimmed back down all on its own. 

Possible reason

I couldn’t gather enough information to clearly state the exact reason for the problem. Maybe your dealer can tell you about it.

Possible fix

The wisest thing to do is take the motor to warranty and not touching it in any circumstance. 

However, we can assume that the trim is operating correctly. After following the break-in procedure correctly, you may see that the problem is gone. 

Warning: doing anything out of ordinary can void the warranty

Now, let’s see how to break in the motor.

  • For the new 150HP 4-stroke engine, the manufacturer recommends everyone to run the first 2 hours at varied throttle settings.
  • Combining the low and high RPM settings, you can go up to 4500 RPMs. Or, you can say 3/4th of the full throttle.
  • After that, run the motor at the highest RPM setting for about 1 minute with 10-minute intervals for the next 8 hours.
  • By all means, you have to avoid running the engine at full throttle continuously for 5 minutes or more at a time.

Also, you have to make sure that your dealer has put the correct battery size. 

2. Coil Problems

The problem goes like this. A user suddenly experienced his Pro XS 150 couldn’t get past 4900 RPM and 49 mph. 

Possible reason

The complainee assumed that one cylinder might be down. However, the problem might be one of the bad coils. 

I’m not saying that the person’s assumption is wrong. Because a faulty coil would cause no spark; hence causing misfiring cylinders.

Possible fix

If the warranty period is not over, you will have to take the engine to the dealer. Otherwise, call a mechanic and replace the bad coil. 

Now, before spending money on a boat mechanic, you can test the coil yourself. Let’s see how to do it.

  • Unplug the wires either from the battery-end or the coil-end. Also, disconnect the spark plug.
  • Get a multimeter or ohm-meter to measure the resistance in the wire.
  • Place a probe of the meter to the positive terminal and another to the negative terminal. 
  • Turn the dial to 200, and see whether the value falls in between 0.02 and 0.04. Otherwise, you should know that the coil is faulty.
  • Those are the test results of the primary circuit, and it is time to see the secondary circuit. Connect the red-colored probe to the negative terminal and the other one to the coil tower.
  • Now, the reading should be between 8 and 11. Anything other than that should indicate a bad or faulty coil.

Once, you have detected the bad coil or you can replace it without expert help by following the steps below. It is very easy to do.

  • After opening the engine cover, locate the ignition coil kit.
  • Know the part number and order a new one matching those numerals.
  • Take the lead and 8mm bolts off. 
  • Next, simply replace the old coil with the new one and connect the wires, bolds, and lead correctly. 

That should do the trick.

3. Engine not Starting

A few customers said that their Mercury Pro XS 150 stopped running after a certain time. 

They suspected the fuel was the culprit although they used the recommended blend.

Possible reason

First of all, no one must use something with more than 10% ethanol as it damages the engine badly. 

Even if you are using the recommended fuel, Mercury suggests not leaving the fuel in the tank for a long time. 

It increases the possibility of corrosion in different metal parts. It can include metal parts, weakening of plastic or rubber parts, fuel lines, etc. 

Possible fix

You can guess the fix right by reading the reason. Maintain the grade of the fuel and don’t leave it for too long.

Tip: You should take this matter seriously. Because the company won’t honor warranty claims if you violate any of the above matters.

4. Warranty Issue

One customer complaint that he contacted Mercury before the warranty period expired. Yet, the company refused to serve him. 

According to the manufacturer, the complainee performed commercial service which reduced his warranty period from a 3-year pleasure warranty to a 1-year commercial warranty.

It appeared that the customer care officials of Mercury were correct. 

What Majority of the Users Feel About Mercury Pro XS 150?

Users suggest that one should not expect much from Mercury Pro XS 150 as it is a low-budget motor. 

However, Mercury produces strong and reliable engines. Compared to competitor models, it can achieve a bit higher RPM. 

Also, the 4-stroke engine is quieter, has better fuel economy, and better idle along with speed control.

Despite some problems mentioned above, it features a fast warmup, fast hole shot, and the motor requires very little maintenance.

Yet, you should not consider it for heavy-duty tasks like fishing in big waters and big waves. Also, it would not be wise to choose this instead of Yamaha if you have the budget. 

Final Thoughts 

Lots of users confirmed that they are happy with the performance of Mercury Pro XS 150. 

It is easy to maintain, runs quietly, and has a good hole shot. Indeed, there are some known issues, but they are not very significant.

If you are seriously thinking about powering up your boat, you will have to consult a mechanic and go for it.

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