How to install an impeller in an outboard motor

They won’t always right themselves right away, especially if well lubed with soap. Also won’t prime itself or pump with vanes in wrong direction. Do it right. Viewed from above, orient the impeller so it turns clockwise.

It’s good outboard maintenance practice to check your water pump impeller every season, and replace it every two to three seasons.

Yes, you will need to drain the lower unit fluid.

When an impeller is running backward, the centrifugal forces will still accelerate the water—although far less efficiently. If the impeller is threaded to the shaft, it may unscrew when running backwards.

The Outboard Motor Overheats

When the impeller needs to be replaced, the motor’s internal temperature rises and the equipment stops taking in cooler water and pumping out warm water. This will eventually lead to overheating, which can leave visible scorch marks on the motor.

The impeller should run around $30/40 and take about 25 minutes or so. The hardest thing is getting the speedo tube back in place. Just apply greese on the bolts and impeller shaft and jog the propshaft and it should go smoothly. The last one I had put in my 50 hp Merc 4 stroke was about $125 installed.

You should check the impeller’s condition during Spring Commissioning and every 200 hours of operation. Correctly installed impellers may last for several years, but you should stick to a schedule of preventative instead of emergency maintenance.

Re: Can a water pump impeller cause engine to not start? Well, the impeller won’t impede the engine from starting, but if you ran it dry and smelt the rubber, you need to replace the impeller now.

If your impeller fails, the pump can’t pump cool water to the engine causing your engine to overheat. If you catch that your impeller is failing early on, you might avoid major problems. However, if you’re not fortunate enough to catch a bad impeller, the results can be catastrophic to your engine.

The pool pump runs but has low water flow.

This means your pump needs to be primed because something has interrupted its suction or water flow. It could be something blocking it, a dirty pool filter, or too much air in the system. If there’s something blocking your pump’s suction, check your filter gauge.

POOL FILTER HAS NO PRESSURE

When the pump is off, or the valve is set to recirculate or drain to waste, the filter pressure should be zero. It could be a clogged pump basket, clogged impeller, clogged pipe or clogged skimmer. It could also be a closed or broken valve before the pump.

One of the most common would be air in the hose. Another common issue is a clogged vacuum hose. Another thing, when you attach that vacuum hose and increases the suction pressure, this could cause the hose that runs from the pool and the intake of your pump to collapse.

Suction-Side Problems

If the vacuum doesn’t work, it’s usually either because air is getting into the vacuum hose or into the suction side of the pool pump. The presence of air in the lines is preventing the system from drawing water as it should.

When a suction cleaner is sluggish or slow, it’s usually a clogged pump basket or dirty filter that is to blame. Other problems include holes in the cleaner hose, sucking air into the hose. Or the filter pump could be drawing in air, reducing water flow volume.