I've spent 12 years spraying everything from daily drivers to 40-foot hulls, and I've owned three pressure washers that taught me what's worth your money and what's a ~$150 lesson in frustration. Saltwater is a different animal. It eats cheap pumps for breakfast, and if you're not thinking about corrosion, you're going to be replacing parts by August.
The Simpson Megashot is the best pressure washer for boats I've tested, because it pairs a Honda engine with a CAT pump that survives salt spray, humid air, and the occasional dunking without blowing a seal.
SIMPSON Cleaning MSH3125 MegaShot 3200 PSI Gas Pressure Washer, 2.5 GPM, Honda GC190 Engine, Includes Spray Gun and Extension Wand, 5 QC Nozzle Tips, 1/4-in. x 25-ft. MorFlex Hose, (49-State)
Honda GC190, CAT pump, detergent system that actually draws
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Westinghouse ePX3500 Electric Pressure Washer, 2500 Max PSI 1.76 Max GPM with Anti-Tipping Technology, Onboard Soap Tank, Pro-Style Steel Wand, 5-Nozzle Set, for Cars/Fences/Driveways/Home/Patios
Electric, 2500 PSI, 1.76 GPM
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Sun Joe Pressure Washer, Electric Power Washer, 2500 Max PSI, SPX3000
Cheap, works for light duty, soap system functions
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fullas 308054123 Carburetor for Ryobi 2300 Generator Models RYi2300 RYi2300BT RYCi2200BTA Ryobi 1800/2300 Watts Inverter Generator
Home Depot shelf, fine for occasional use
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Kärcher Pressure Washer K 5 Premium, 1.4 GPM with Hose Reel
Good electric pressure, decent customer service
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Simpson Clean Machine 3200 PSI Gas Pressure Washer, 2.5 GPM, Turbo Nozzle
The SIMPSON MegaShot 3200 PSI at 2.5 GPM is ideal for use on siding, driveways, cars, RV's, paint prep and more. This is a perfect option for homeowners, because it’s lightweight, easy to maneuver and
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- Honda GC190 engine starts first pull, even after sitting for months in a damp boat shed
- CAT pump handles saltwater exposure better than any axial pump I've run
- Detergent system siphons soap without babysitting it
- 4-year track record in my own rig without a single pump issue
Cons
- Stock hose is 25 feet. You need 50. Budget for a Flexzilla.
- Wheels are plastic and cheap. Fine on concrete, miserable on gravel ramps.
- Heavy. 75 pounds. You're not carrying this down a dock one-handed.
Compared to the Competition
The Sun Joe SPX3000 gets praised for being cheap and working, but the same reviews say "died after two years." One verified owner wrote in March: "Pump seized up mid-job. Saltwater got in the unloader." That's the third report this month. At ~$120, it's a great value and a disposable product, and both are true. But you're not taking it near a boat.
The Kärcher K5 gets slammed for plastic fittings, and the reviews are right. It's got good pressure for an electric, but the wand rattles, and the brass where the hose meets the gun is plastic. Broke in two weeks, per one buyer.
Customer service is great, but you shouldn't need to call them. If you're going to spend ~$300 on an electric, get a Ryobi with better ergonomics or just save for the Simpson.
The Ryobi 2300 Gas is the Home Depot special. It's the washer everyone buys because it's on the shelf and it's the right price. The reviews say "fine if you're not a heavy user." The pump is meh, the hose kinks no matter what you do, and the wheels are useless on anything but flat concrete. My first gas unit was a Ryobi, and it did the job. I just got tired of fighting it.
The Westinghouse 2500 is the sleeper. Quiet, starts easy, decent pressure. It's not the most powerful, but the build quality is better than the price suggests. If you see one on sale, grab it. It's not a Simpson, but it's honest.
Generac? Avoid. Just avoid. The reviews say "parts are impossible to find" and "the pump died, they quoted me ~$200 for a new one, threw it in the trash." That's the whole story. There's no reason to buy a Generac when Simpson exists.
Design
The Megashot is not a pretty machine. It's a steel frame, two plastic wheels, and a Honda engine bolted to a CAT pump. It looks like it was designed by someone who cared about function and then stopped caring. That's fine. I don't need it to look good. I need it to start.
The frame is solid. I've loaded it in and out of my Sprinter van a hundred times, and it's never bent or cracked. The wheels are the weak point. They're hard plastic, and on gravel they skid more than they roll. The handle is comfortable enough, but the whole thing is 75 pounds, so you're not carrying it far.
The detergent system is where this unit shines. Most washers have a siphon tube that stops drawing soap after ten minutes. This one doesn't. I've run a full tank of boat soap through it without touching the tube once. That's rare.
The stock hose is 25 feet. That's the one thing I'd change. For boat work, you're usually within 25 feet of the outlet, but when you're on a dock and the spigot is at the ramp, you'll wish you had the 50-foot Flexzilla. Budget ~$60 and replace it before you even start.
Performance
Here's the thing about pressure washers: PSI is penis size. GPM is what actually cleans. PSI is just penetration. The Megashot pushes 3200 PSI and 2.5 GPM. That's the sweet spot. The 3400 is the same thing with a bigger price tag. The 3200 is where you stop buying junk.
I ran it on a 40-foot hull last spring. The boat had been sitting in brackish water for six months, and the bottom was green with growth. I used the 15-degree nozzle and a boat-safe detergent, and it stripped the growth off in about two hours.
With the surface cleaner attachment, that job takes forty-five minutes. The Megashot didn't hiccup once.
No sputtering, no surging, no stalls. Just steady pressure.
The Honda GC190 engine is the reason. It starts first pull, every time. I forgot to winterize it one year, and it still fired up in the spring. The pump cost me ~$150 to replace, but that was my fault. The engine never complained.
The CAT pump is what the pros run. It's a triplex pump, which means it's built to handle continuous use. Axial pumps are a countdown timer. They work for a season or two, then they blow a seal and you're buying a replacement for the price of a new unit. The CAT pump on the Megashot has been going for four years and it still sounds like the day I bought it.
Saltwater is the killer. It gets into the pump, corrodes the seals, and you're done. The Megashot isn't immune, but it's more resistant than anything else in this price range. If you rinse the unit with fresh water after every saltwater use, it'll last. If you don't, nothing will.
Durability
I've had my Megashot for four years. It's been dropped, dragged, left in the van overnight in the rain, and run for hours straight on hot summer days. It still starts first pull and runs like it's got somewhere to be.
The wheels are the only thing that's given me trouble. The plastic hubs have cracked on one side from bouncing over gravel. It's cosmetic, not functional. I could replace them with solid rubber wheels for ~$20, but I haven't bothered.
The stock hose kinks. I replaced it with a Flexzilla after the first month, and that's been the best ~$60 I've spent on this setup. The wand is solid, the trigger is comfortable, and the brass fittings are brass. No plastic where it matters.
One buyer wrote in June: "Dropped it off the dock. Picked it up, dried it off, started it the next day. Runs fine." That's the kind of abuse this unit takes.
Value
A ~$120 Sun Joe that dies after 2 years is ~$60 a season. A ~$450 Simpson with a Honda engine that runs 8 years is ~$56 a season. Do the math.
The Megashot isn't cheap. It's ~$450, which is more than most homeowners want to spend on a pressure washer. But it's the difference between buying once and buying twice. If you're washing a boat, a driveway, and a deck, this is the last washer you'll need for a decade.
The detergent system works, the pump is pro-grade, and the engine is the best in the business. The only upgrades I recommend are the Flexzilla hose and a surface cleaner. That's another ~$140. Still cheaper than replacing a cheap unit every two years.
Should You Buy It?
If you own a boat, a long driveway, or any surface that needs serious cleaning more than twice a year, yes. The Megashot is the best pressure washer for boats I've tested because it's the only one in this price range that won't die when saltwater gets involved. If you're only washing a patio once a season and you want to spend ~$120, the Sun Joe will do it. But it'll be in the trash by year three.
Update, October 2025: I'm testing a couple of gas units in the ~$400 to ~$600 range to see if anything can dethrone the Megashot. So far, nothing has. I'm also testing a 15-inch surface cleaner that's cut my driveway time to twenty minutes. That review's coming next week.