Remove flywheel

[ej14]

We have an oil leak by the flywheel. What is the procedure for removing the flywheel? If the slinger ports are clogged, is it simply a matter of cleaning them?

thanks
ej

[Don Moyer]

The flywheel can be taken off by removing the six 3/8" retaining nuts securing it to the end of the crankshaft. These nuts have a 35 foot-pound torque specification when re-installing the flywheel.

You can usually work a piece of safety wire past the outer edge of the collar of the slinger seal and into the drain holes to clear them.

Here is a technical note we prepared on the subject of oil leaks behind the flywheel:

There are three primary sources for oil leaks appearing below the flywheel housing (listed somewhat in order of likelihood):

1) Overfilling the crank case. There is no conventional seal in front of the crankshaft, and if the crankcase is overfilled by much more than a quart or so, some oil can splash out of the front of the engine, just behind the flywheel, especially when sailing in choppy water.

2) A leaky gasket between the flywheel housing and the front of the block. Such a leak would be very unusual, except possibly immediately after an overhaul.

3) There is no traditional oil seal in the front of the crankshaft. The Atomic 4 has what is called a "slinger" seal to prevent oil from escaping from the crankcase. The slinger seal consists of a collar machined around the front of the crankshaft where it extends out through the flywheel housing, just behind the flywheel. The outside edge of this collar is sharpened to a dull edge which lines up with the inside diameter of the hole in the flywheel housing. When oil tries to leave the crankcase, it encounters the crankcase side of this collar, and gets "slung" outward (hence the name "slinger seal") into a groove cut into the inside diameter of the hole in the flywheel housing.

There are small drain holes (approximately 5) in the bottom of the groove around the inside of the hole in the flywheel housing, which allow the oil to flow back into the crankcase after it is flung outward into the groove by the edge of the sharpened collar on the crankshaft. Every now and then, those holes get clogged with crud and oil cannot flow back into the crankcase as fast as it is being flung out by the slinging collar.

NOTE: In even more rare cases, we have had oil reported to be dripping out of the front of a Delco starter housing, with no other indications of an oil leak at the flywheel end of the engine. The oil was determined to have come from clogged slinger seal holes, from where it was subsequently flung out to the starter drive unit by the flywheel.

Best regards,

Don Moyer

[sailorman]

have same starter/flywheel problem. after reading dons great
help line will go back to the boat and try again...i love moyer
marine as i have a 1971 cal with A4 and will not change it....

capt Mac