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Simpson MSH3125 MegaShot Review

This pressure washer is a beast of a machine that will tackle heavy-duty projects with ease
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Simpson MSH3125 MegaShot Review
Price:  $450 List
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Manufacturer:   Simpson
By Austin Palmer and Ross Patton  ⋅  Nov 26, 2019
  • Cleaning - 45% 10.0
  • Portability - 30% 5.5
  • Noise - 15% 2.2
  • Ease of Use - 10% 3.0

Our Verdict

The Simpson MSH3125 MegaShot is simply a powerhouse of a tool. With a Honda GC 190 4-stroke engine running the pump, you can rest assured that it has ample power for the toughest projects you can throw at it. It includes lower pressure nozzles and a soap siphon hose, so it can be used for lighter duty tasks as well. One of our favorite features about the MSH3125 MegaShot is its large rubber tires which help the user push or pull this machine over grass, gravel, and gnarly terrain. This model is a spectacular pressure washer, but it is on the heavier, louder, and bulkier side.
Incredible cleaning power
Large all-terrain tires

Our Analysis and Test Results

The main element that separates the MSH3125 MegaShot from the competition is its outstanding cleaning capabilities. When it comes to cleaning units, this model is hard to beat — it has ample power for just about any consumer-level project. On top of that, the tires on the Simpson are mounted on metal rims and are composed of inflatable rubber rather than the hard plastic wheels that most other pressure washers use. This is very useful to help with grip on gnarly terrain.

Performance Comparison

simpson msh3125 megashot
Credit: Ian Pearman


We set the cleaning metric to account for 45% of the total score as it is the most significant deciding factor for most people that are shopping for a pressure washer. For this metric, we ran a variety of tests and the Simpson MSH3125 MegaShot did not disappoint during the process. We looked at three different variables — measured cleaning units, subjective cleaning power, and our own bocce ball pressure test.

The second that we depressed the trigger on this machine we knew that it meant business. During our subjective scoring of this model, it blew pine needles and debris out of gutters like a leaf blower, it stripped the stain off wood siding, and it cleaned the grime off of two-story buildings with its lower degree nozzles. When we judged how long it took to clean a carpet covered in activated charcoal, the MegaShot showed a terrific level of performance.

To measure cleaning units, we used an inline pressure gauge to take a PSI reading, then we weighed how much water the machine dispensed in a one minute period. To calculate cleaning units (CU) these two figures are multiplied. The Simpson put up some fantastic numbers during our CU analysis.

To translate the cleaning power of each pressure washer into visual terms, we built a wooden trough at an angle of 24 degrees to see how high each machine could hold a standard bocce ball. The MegaShot showed fantastic performance for this assessment — it held a ball 7 feet up the trough.

simpson msh3125 megashot - the simpson held a standard bocce ball 7 feet up a ramp adjusted to...
The Simpson held a standard bocce ball 7 feet up a ramp adjusted to 24 degrees.
Credit: Ross Patton

The great thing about having a unit with extra power is that you can still dial it down by using a nozzle with a larger angle to widen the spray and decrease the pressure for lighter jobs.

simpson msh3125 megashot
Credit: Ian Pearman


The MegaShot isn't very portable when it comes time to transport it with a vehicle. At 62.5 pounds, it's quite a pain to lift off the ground. It might fit in certain cars, but a truck or trailer are both more suited to haul it around. That being said, once it's at the job site or property, it is one of the easiest to move around. While scoring this metric we looked at both moving the machines from place to place as well as rolling them around, the MegaShot is much stronger in the latter.

Unlike models that have plastic wheels, the Simpson has inflatable rubber tires mounted on steel wheels. Rubber tires are much better at gripping dirt, rocks, and wet surfaces than hard, slippery plastic.

simpson msh3125 megashot - the simpson msh3125 megashot comes with beefy rubber tires that...
The Simpson MSH3125 MegaShot comes with beefy rubber tires that maximize grip in all sorts of terrain.
Credit: Ian Pearman

The combination of the low center of gravity along with the location of the handle gives the MegaShot a decent balance — it's actually very easy to roll around.

simpson msh3125 megashot
Credit: Ian Pearman


Our next metric focused on the noise levels produced by each pressure washer and accounts for 15% of the total score. We took measurements from directly next to the machine as well as from 25 feet away. We also made a subjective judgment of pitch in case there were any sounds that were especially loud and annoying that the meter wasn't picking up on.

Unfortunately, the Simpson scored terribly in all of our assessments for this metric. The operator of the pressure washer will be subjected to an ear-splitting 93.2 decibels. At a distance of 25 feet, the sound drops to 80.1 decibels which is still very loud.

Also, unlike many electric models that only make noise when the trigger is depressed, the MegaShot is constantly running so your ears won't get a break until the motor is turned off.

simpson msh3125 megashot - with the added power of gasoline comes added chores.
With the added power of gasoline comes added chores.
Credit: Ian Pearman

Ease of Use

We dedicated the final 10% of the total score to ease of use. There were several ways in which the Simpson MSH3125 MegaShot lost points for this metric. Some pressure washers have the hose connection located on a part of the machine that is easy to access, this is not the case with this model. The connection is in a tight spot, and it's really close to the frame which is frustrating and annoying.

simpson msh3125 megashot - the hose connections are very close together on this model.
The hose connections are very close together on this model.
Credit: Ross Patton

The hose storage is a very wide hook with nothing else in place to secure it. The hose itself is pretty stiff, which makes it a bit of a challenge to roll up.

simpson msh3125 megashot - the hose on the simpson is bit difficult to deal with, but once it's...
The hose on the Simpson is bit difficult to deal with, but once it's rolled up its tidy.
Credit: Ian Pearman

The main reason that the MegaShot scored so low for this metric involves its maintenance. With a gas-powered model, you're taking on all of the potential problems and chores that come along with an engine.

We considered the need for a gas can, an oil funnel, and regular tune-ups. To get this model started you need to pay close attention to the position of the choke lever and then you have to yank on a pull cord. Gas-powered engines are often finicky and require oil changes, carburetor cleanses, and spark plug changes.


The Simpson is one of the most expensive pressure washers that we've reviewed, but if a high level of performance is crucial for you, it's well worth the money.


To sum it up, the Simpson MSH3125 MegaShot is an excellent pressure washer. The cleaning power of this tool is hard to match, but it brings the problems and maintenance of a gas-powered engine. It's a good option for people that want extra power and aren't worried about doing a little wrenching now and again.

Austin Palmer and Ross Patton