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post #1 of 4 Old 07-09-2004 Thread Starter
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cutlass bearing ruined?

hi -- started my atomic 4, first inboard i''ve had, but now i''ve done enough research to realize i should not have run the engine in gear, even briefly, out of water -- again, not having had an inboard before, i didn''t realize this -- fortunately it was brief, about 20 seconds -- what damage might i have done, and is there a way to assess this before launching -- keep in mind that the previoous owner, who had more sense than i did, had installed a new shaft and associated parts -- when i check the bearing, i find no play, much squeakiness if i turn by hand, and a small 1/4" piece of rubber extruding from between the shaft and bearing

also, still wondering why, when in neutral, the engine vibrates so much when revved up(on the hard), even though it is well-tuned, running on all cylinders with full compression -- or perhaps i shouldnt'' be doing this either?

thanks, bob
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post #2 of 4 Old 07-09-2004
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cutlass bearing ruined?

Doubt very much if a 20 second run hurt the cutlass. By what you described it is tight and it would squeek out of water. Not a good idea to run the boat on the hard either without a cooling water source. Good luck with the old A-4
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post #3 of 4 Old 07-09-2004
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cutlass bearing ruined?

You probably did no damage at all to the cutless bearing. When turned when dry its normal for a cutless to squeek. It takes many minutes to heat up the bearing surface with a dry shaft to do any harm.

Proper clearance (assuming precise shaft/engine alignment) for an (installed) cutless is somewhere near 0,003-0,005" per inch of shaft diameter ...... something that you''re not going to feel by shaking and pulling on a propshaft.

Vibration in a (warmed up) A4 @ high rpm no load idle is probably due to a dirty/gummed carburator or different compression values between the cylinders. You might want to do a cursory compression check to verify that exhaust valves are not ''hanging-up'', possibly a head gasket that is just starting to ''blow'' or piston rings that are partly sticking in their grooves. I''d run the engine moderately hard for quite a few hours before making any decision because if the engine has set idle for a long time, it will take a while for the internals to ''repolish'' themselves from the normal rust ''bloom'' that forms (if the engine wasnt properly fogged when shut down and stored).
The carburator (emulsion tube) is very sensative to gum formation from old stale fuel. If the tube is gummed up or has the teensiest bit of dirt on it the engine will run rough. If the carb doesnt have an adjustable main jet, consider adding one.

Go to and get yourself Don Moyer''s A4 maintenance manual - best investment you can make on an old A4. Don is the world''s "authority" on A4s. Most ''yard'' mechanics have long forgotten how to ''peak'' this engine and will replace-everything-under-the-sun and cost you $$$$ with little result. Get Don Moyers book and easily become your own A4 mechanic. These old engine harldy ever wear out, they just rot away from the inside, consider to add freshwater cooling to preserve the life.

good luck.
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post #4 of 4 Old 07-09-2004
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cutlass bearing ruined?

With the boat out of the water there are a few things that need to be considered. The hull is not in it''s natural shape due to the unequal stress. The water also acts as a shock absorber for viberation. The shaft maybe out of alignment due to the stress on the keel. Motors should always be aligned while in the water. The clearance in the cutless bearing should not have more then a slight movement . the squeak is a good sign. If you need to spin the prop for whatever reason some lithium grease forced into the groves or a waterhose running thru the bearing works for short peroids.
And one thing to remember with gasoline engines is the the fuel lines and connections need to be in top condition as well the bilge blower working properly blowing INTO the engine compartment and out the vent. If you can smell gas, you have a problem!
One problem of running the engine out of the water is the impeller of the raw water pump can be damaged. Always carry a spare impeller anyway.
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