Johnson Engine Testing

The engine that came with the boat is a 35HP 1957 Johnson Javelin. It is a 2-Cycle engine, and it has electric start, however it does not have a generator or alternator so it does not charge the battery.

35 HP Johnson Javelin

The previous owner didn’t have much information on the engine, but it appears to be in excellent condition. To get ready to start the engine I replaced the plugs, and had to get a pressurized gas tank off of ebay. These engines don’t have fuel pumps, instead they take pressure from the tank, feed it through a secondary fuel line into the tank to pressurize the tank, which then forces fuel back up to the engine and into the carb.

The tank I bought off ebay had some some serious leaks, I had to order a new gasket set and rebuild the top half of the tank.

After some fiddling, and eventually some compressed air, I was able to get the tank to pressurize enough to fill the engine mounted fuel filter and the bowl on the carb.

I jury-rigged a start solenoid and switch, and after a few clicks it lit right up!

It ran pretty smooth considering it hasn’t been run in over 5 years, but the impeller would appear to be shot as it wasn’t passing water. I’ll have to replace that once the boat is ready to go in the water.

I love simple 2-stoke engines, they don’t take much to maintain, and they typically will outlast the boat.

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