testing under load

[mikke60]

Does anyone know of a way to test their engines under a mock load while up on stands. My engine ,like many others,runs great under no load. Once I get her in the water ,its another story. She runs fine at the mooring,but hesitates under any more than quarter throttle. Any idea's how to mock a load without damage?
Thanks, mike

[hanleyclifford]

When on the hard I test my engine under load by running the 2000w inverter and switching on the toaster oven (full tilt). This mimicks a load of about 4 HP. This only works if you have a big alternator and are prepared to put the screws to it. It is possible that you have other issues that need to be addressed such as exhaust back pressure or even fuel supply. Now is a good time to test that exhaust system.

[JOHN COOKSON]

Possible carburetor main jet blockage?

TRUE GRIT

[joe_db]

You could link the engine to a 20-30 KW generator and make a load bank.

[Al Schober]

There was a proposal some years ago to test submarine propulsion systems to full power dockside. Power would have been absorbed by a water brake - a substitute propeller with infinite pitch. A band around the blade tips would have kept water from being thrown onto the dock.
I see a 55 gallon drum with a bearing/stuffing box on the side, a short piece of shafting, and a fabricated water brake wheel... Anyone else see it?

[hanleyclifford]

I can see it. The drum will have to be mounted on something akin to a transmision jack so the unit can be raised to the boat's shaft. The water brake unit will have an extension with a tapered female fitting to go over the boats drive shaft.

[mikke60]

how would I go about checking exhaust? I replaced exhaust manifold and piping 2 seasons ago.. thanks

[hanleyclifford]

The number 1 best way to test exhaust is to have the MM exhaust flange with the extra port for the pressure gauge. Failing that a laborious inspection of the soft components is made piece by piece. The biggest offender seems to be collapse of the inner wall of hoses which creates a restriction that is not obvious viewed from the ouside. This is a good possibility if you have ever had an overheating event or an extended running with no discharge water.