How often should I change the oil in a Simpson MegaShot MSH3125-S?

Change the oil in the Simpson MegaShot MSH3125-S every 50 hours of run time. Because it is measured in engine hours, log the hour-meter reading rather than a date.

What is the maintenance schedule for a Simpson MegaShot MSH3125-S?

The Simpson MegaShot MSH3125-S is serviced on engine hours, not miles. Key intervals include Clean Air Filter (every 25 hours), Engine Oil Change (every 50 hours), Check/Adjust Spark Plug Gap (every 100 hours). Track the hour meter and service each item when its interval comes due.

Does the Simpson MegaShot MSH3125-S track maintenance by hours or miles?

By hours. Small engines and heavy equipment log run time on an hour meter, so their service intervals are hours-based. ServiceSage Auto tracks the Simpson MegaShot MSH3125-S by hours and reminds you when each service is due.

Simpson MegaShot MSH3125-S Maintenance Schedule

Simpson MegaShot MSH3125-S maintenance — the short answer

Oil: SAE 10W-30, API service category SJ or later · 20 oz (0.58 L) · every 50 hrs
Engine: Honda GC190 4-stroke OHV, single-cylinder, air-cooled (confirmed via Simpson's MSH3125 Illustrated Parts List item #2, ENGINE, HONDA GC190); OEM Technologies axial cam pump with thermal relief, maintenance-free/sealed - no oil drain or fill plugs
Tracked by: engine hours, not miles

Simpson MegaShot MSH3125-S maintenance schedule by engine hours

Interval	Service	Details
Every 25 hours	Clean Air Filter	Clean the air filter every 25 hours or 3 months; more often in dusty conditions.
Every 50 hours	Engine Oil Change	Change engine oil every 6 months or 50 hours (every 25 hours when used under heavy load or in high ambient temperatures). First change at 5 hours as a break-in service.
Every 100 hours	Check/Adjust Spark Plug Gap	Check and adjust the spark plug gap (0.028-0.031 in / 0.7-0.8 mm) every 100 hours or annually.
Every 100 hours	Spark Arrester Clean	Clean the spark arrester every 100 hours to keep it functioning as intended.
Every 100 hours	Idle Speed Check/Adjust	Check and adjust idle speed every 100 hours or annually. Servicing dealer item.
Every 100 hours	Fuel Tank and Filter Clean	Clean the fuel tank and filter every 100 hours or annually. Servicing dealer item.
Every 100 hours	Valve Clearance Check/Adjust	Check and adjust valve clearance every 100 hours or annually. Servicing dealer item.
Every 250 hours	Air Filter Replace	Replace the air filter element every 250 hours or 2 years.
Every 250 hours	Spark Plug Replace	Replace the spark plug (NGK BPR6ES) every 250 hours or 2 years.
Every 250 hours	Combustion Chamber Clean	Clean the combustion chamber after every 250 hours. Servicing dealer item.

Simpson MegaShot MSH3125-S specifications

Type: Pressure Washer
Engine: Honda GC190 4-stroke OHV, single-cylinder, air-cooled (confirmed via Simpson's MSH3125 Illustrated Parts List item #2, ENGINE, HONDA GC190); OEM Technologies axial cam pump with thermal relief, maintenance-free/sealed - no oil drain or fill plugs
Displacement: 187 cm3 (11.4 cu-in)
Oil type: SAE 10W-30, API service category SJ or later
Oil capacity: 20 oz (0.58 L)
Spark plug: NGK BPR6ES, gap 0.028-0.031 in (0.7-0.8 mm); Honda cross-reference 98079-56846

Simpson MegaShot MSH3125-S items without a fixed hour interval

Engine Oil Level Check: Check the engine oil level before each use.
Air Filter Check: Check the air filter before each use.
Fuel Tube Inspect/Replace: Inspect the fuel tube every 2 years and replace if necessary. Servicing dealer item.
Pump Service: The pump is a factory-sealed, maintenance-free design filled with oil at the factory - it has no oil drain or fill plugs and needs no owner service.
Hose/Gun/Pump Connections Lubricate: Clean and lubricate hose, spray gun, and pump connections with a thin film of lithium grease regularly to prevent O-ring damage and leaks.
Water Inlet Filter Clean: Check and clean the water inlet filter before each use.