Engine Resurrection: 1 + 1 = 1

Upon initial inspection, it was determined that this engine had suffered considerable corrosion damage, presumably from salt picked up during testing.

The air filter housing was missing, and it was recalled from previous operation that the carburetor was in a questionable state at the time when active use of this motor was discontinued.

Upon removing the fuel tank, the governor mechanism was found to have suffered considerable corrosion damage.

As a result, the governor unit from the damaged engine was swapped in place of the rusted unit. As seen here, the difference in condition was clear.

The CVT was removed from the output shaft of the engine with some difficulty. The key was found to be damaged, and the shaft corroded. This part will need attention before a drive mechanism can be remounted. The CVT that was removed was badly rusted.

At this point it was noted that the engine would rotate, but could not be turned over through a complete cycle. This suggested that there was some obstruction in the cylinder, a damaged rotating assembly, or interference from the valvetrain. To investigate the problem, the valve cover was opened (necessary for inspecting the valvetrain, or removing the head, making it an obvious first step) and it was quickly observed that one of the valves was seized in its guide. In this photo, though somewhat obscured, the gap between the rocker and the seized valve is apparent. This failure could be arresting the engine in one of two ways. Either the valve that was sticking open was being hit by the piston, impeding further rotation of the crack, or else the rocker was unable to depress that valve to open it further, resulting in a jam through the cam mechanism. In either case, this cylinder head would not be suitable for service without significant repairs and machining.

The damaged clyinder head was removed from the engine, and the combustion chamber and valves, along with the exhaust port, were observed to be badly corroded. It is anywhere from possible to likely that salt water infiltrated the cylinder head, and combined with the stagnat time spent on the shelf, resulted in the damage seen.

The piston and cylinder were found to be corroded and full of debris. It looks like someone may have tried to use this engine as a makeshift slurry pump.

The spark plug was removed and found to be corroded badly, including a bridge across the electrode gap. It was replaced when the engine was reassembled.

Here is the head and intake assembly from the damaged engine. As that photo illustrates, it is in much better condition, showing clean mating surfaces and little corrosion on the internals. The valvetrain was found to be free and undamaged, so it was pressed into service.

The cylinder, piston, and block mating surface of the engine casting were cleaned.

A serviceable head gasket was mounted to the centering posts.

The magneto from the corroded engine (right) was, predictably, found to be badly corroded. The unit from the damaged engine (left) was found to be in more acceptable condition, so it was used instead during reassembly.

The cylinder head was mounted to the engine block, the push rods were inserted into the engine, and the valve lash was set to feel. Valve lash should be checked and adjusted after these components have had a brief run in period.

The valve cover was installed, and the governor assembly was attached. It was later discovered that the engine would not hold idle while running, suggesting that this mechanism requires adjustment.

The exhaust manifold from the corroded engine (right) was substituted out in favor of the manifold from the damaged engine (left). This made eminent good sense, as that was the manifold that was originally mounted to the cylinder head being used anyway.

The exhaust manifold was attached.

The recoil housing from the corroded engine (left) was compared to the housing from the damaged engine (right).

Based on condition, the housing from the damaged engine (lower) was determined to be more serviceable.

However, slight variations in the design of the two parts caused clearance issues with the cylinder heat shield, resulting in the reuse of the corroded housing.

The gas tank was plumbed and attached to the engine, and after completely disassembling and reassembling the motor again to install the kill switch lead which had not been attached to the magneto, the engine was ready for testing. It was found to run, with exhaust gas issues stemming from the reused gaskets, and idle issues resulting from the uncalibrated governor mechanism. Both issues should be resolved shortly.

I welcome any questions, comments, or concerns.