Sherwood Pumps

The history of Sherwood Pumps goes back to the beginning of the 20^th century, when William Sherwood expanded his plumbing store into a foundry and machine shop. In the 20ies, Chris Smith and his company, Chris-Craft, incorporated Sherwood Pumps into the first inboard powered yachts, technically developing the first sea water pumps for marine engines. During the two decades between the two world wars, the demand for pleasure boating increased rapidly and Sherwood kept up with the demand, creating cooling solutions for Chrysler, Ford and GM by continuing, expanding and developing relationships with Chris-Craft, Chrysler Marine, Crusader, and OMC.

Fast forward into nowadays, Sherwood Pumps is a brand within the Pentair group, globaly known for its quality and durability. The Sherwood Water Pumps offer a wide variety of service parts that optimize the maintenance of your pump, depending on the use of your boat. It is common sense that a leisure boat will have less wear than a fish-farm boat that operates in silty waters daily and year-round.

By observing the wear pace of your sherwood water pumps, you minimize the chance of a sudden engine overheat. Questions like “How often should an impeller be replaced?” cannot be answered simply, without taking into consideration the use you put onto your boat. Typically, a Sherwood water pump impeller should be replaced every year when the use of your boat is light duty (pleasure boating with low hours). If the use is more intense, or you use your boat in silt and sand, it is advised every six months. When it comes to commercial use, the aforementioned periods are shortened to 6 and 3 months, respectively. Further parts are required to be replaced within your maintenance cycle so as to keep your pump in working condition. A minor kit is needed bi-yearly/yearly for pleasure boating (light duty/severe duty), while for commercial boating, it is required yearly/twice a year (heavy duty/severe duty). Lastly, a major kit is required every 4 years/2 years for leisure activity or every two years/yearly for commercial use. A Sherwood water pump impeller kit is usually made up of an impeller and its relevant installation(s) gasket(s). A minor repair kit includes all the above, plus snap rings and/or a mechanical seal and a wear plate if needed. Lastly, a major kit includes all the aforementioned parts, plus bearings, a cam, and often a water pump shaft. Of course, all these parts are varied as per the intended pump model to repair. Engine overheating is the primary cause of premature engine wear, and any issues with the impeller can result in this.

Under the scope of preventive maintenance, in order to prevent expensive repairs, Sherwood Pumps is suggesting the following tips:

Impeller: Check for tears or cracks. Additionally, check for severe vane end abrasion. Replace every year, or as shown in the image below, if any of the criteria are present:

Wear Plate: Examine the pin for wear, flatness, and fatigue.
To preserve pump flow and suction performance, replace during a major pump rebuild or if wear is noticeable.
Cam: Replace during minor or major pump rebuild or if pitting/wear is evident.
Cover: For optimal pump flow and suction performance, replace during a major pump rebuild or if wear is present.
Mechanical Seal: Replace when the pump is leaking or through a small or major rebuild.
Lip Seal: Replace if the pump is leaking or undergoes a major rebuild.
Shaft: Check for wear at the rubber impeller and lip seal.
Replacement of the shaft will be necessary if the lip seal area has grooves or if the impeller end shaft has significant fretting.
Bearing: Check for corrosion, harsh rotation, or grease loss.
Replace the whole shaft and bearing assembly during a major pump rebuild.

Three tips to help you install your new impeller and ensure its proper function:

To make it easier for the impeller to slip into the housing, use a non-petroleum lubricant, such as silicon-based or soapy water.
Twist the impeller onto the shaft to install it. An impeller should never be forced onto the shaft. For the impeller to prime and operate correctly, it must have unrestricted movement on the shaft.
When changing the cover, apply a tiny bit of non-petroleum lube to assist retain the o-ring in place.

During an extended period of disuse, the impellers' lifespan can be preserved by properly storing them.
After removing the impeller from the housing, keep it somewhere cool and dark. By doing this, the following will be avoided: