The venerable, but discontinued, Universal Atomic Four gasoline engines is often affectionately called the "Atomic Bomb". The original engine installed in my boat, Mystic, in 1975 is still going strong, with no major repairs. The Universal Motor Company started business as a marine engine manufacturer and the A-4 was designed from the ground up as a marine engine. It even utilized special corrosion resistant metal alloy's. Of the 40,000 A-4's originally installed between 1947 and 1985, in boats from 25' to 41', around 20,000 of these reliable little engines are still in use. At thier peak Universal had 85% of the sailboat market. For more interesting facts on the history and design of the engine, visit the Atomic Four Engine Service web site by Robert Hess Over the years owner's manuals often get lost. Below you can view and download a digital copy of the one that came with my boat. This Universal Motors manual is not copyrighted. Each image (1-2 pages) can be viewed seperatly so you can read or copy only those that you need. Small diagrams have been enlarged so you should be able to read just about all of the text in the diagrams.
ATOMIC FOUR OWNER'S MANUAL:
Document Description TOCA4.TXT 9k A text version of this Table of Contents A4Cvr.GIF 32k Front cover only A4Pa.GIF 68k Engine Operation & Important Note A4Pb&P01.GIF 90k Warranty & Page 1 P02&3.GIF 95k Page 2 & 3 Engine Specifications P04DD.jpg 68k Page 4 installation dimensions, Direct Drive P04RD-AP.jpg 90k Page 4 installation dimensions, Reduction Drive & Aqua Pack P05Stbd.GIF 90k Page 5 Photo Starboard (right) side engine P06Port.GIF 90k Page 6 Photo port (left) side engine P07.jpg72k Page 7 Gen. suggestions & exhaust diagrams P07F1-2-3.GIF 63k Page Enlarged exhaust diagrams P08&9.GIF 122k Page 8 Suggestions before starting, Page 9 Zenith 61 series Carberators P10&11carb.GIF 108k Page 10 & 11 Zenith 68 series carberators A4carbA.GIF 77k
Page 10 Enlarged Carburetor Diagram A A4carbB.GIF 68k
Page 10 Enlarged Carburetor Diagram B A4carbC.GIF 63k
Page 10 Enlarged Carburetor Diagram C P12&13.GIF 113k Page 12 & 13 Electrical Diagrams P14&15.GIF 131k Page 14 Electrical, Page 15 Cooling system P16&17.jpg 126k Page 16 Oil circulation, Page 17 Valves, ignition, safety P18&19.GIF 126k Page 18 Transmission adjustment Page 19 Water pumps, generator, V-drive P20&21.GIF 104k Page 20 & 21 preparing for spring service and winter storage P22&23.GIF 113k Page 22 & 23 Trouble shooting P24&25.GIF 104k Page 24 & 25 Trouble shooting P26.GIF 36k Page 26 A Final Word
The following are not part of the Owner's Manual
A4BrochF.GIF 197k Atomic Four Brochure Front Page A4BrochB.GIF 167k Atomic Four Brochure Back Page A4Parts.txt 26k This text document lists parts, suppliers and maintenance information. I suggest you print it out and keep a copy aboard as a reference. A4Tips.html 128k: NEW IMPROVED: collection of maintenance/repair tips for the Atomic Four Engine Port Side: Original A4 engine (Serial #s 170507 & older). Starboard Side: Original A4 engine (Serial #s 170507 & older). FUELPUMP.GIF Mechanical fuel pump rebuild diagram provided by Terry Kuhn - Engines by TK FUELPUMP.TXT Mechanical fuel pump rebuild instructions provided by Terry Kuhn - Engines by TK Dirty Carberator If you have never overhauled your carberator, the photographs on this page make it clear why you should consider doing so. A4Mechanics.txt List of Atomic Four Mechanics, USA & Canada A4 muffler Photograph of A4 muffler installation. Oil Pump Out I installed a tee and valve on the oil pressure take off port so that I can use the engines oil pump to remove the oil. Read more about it here. What is this? strange device inserted in alternator wire by previous owner (PO), it is in the alternator wire that connects to the positive terminal of the coil. The pencil notes on the diagram are from the PO Step 1 Step 2 Step 3 Step 4 Step 5 These photo's illustrate the steps to remove a rusted Galvanized Iron pipe from the exhaust manifold fitting. These fittings are expensive so worth a little effort ot salvage them. NewExhaustA: Comparison A new and old exhaust pipes. NewExhaustB: Comparison B new and old exhaust pipes. A4 wiring diagram: I've combined the information shown on several different A4 wiring diagrams, you may find this useful reserved: Photo of burnt out Petronix Electronic Ignition. This component will burn out if the ignition key is let on when the engine is not running. This also burns out coils. Neither of these problems were documented by the A4 Owner's manual or the Petronix installation instructions at the time when I bought this ignition. Subsequently I learned that electronic ignitions are very hard to diagnose when they malfunction. I've gone back to the much more reliable and easy to diagnose breaker point system. reserved: --- reserved: ---
Over the years owner's manuals often get lost. Below you can view and download a digital copy of the one that came with my boat. This Universal Motors manual is not copyrighted. Each image (1-2 pages) can be viewed seperatly so you can read or copy only those that you need. Small diagrams have been enlarged so you should be able to read just about all of the text in the diagrams.
...The amount of oil that an Atomic Four engine can hold varies with the angle or slope at which it is installed. Most Pearson hull sections that I have seen indicate that the engines are installed at around 14-15 degrees from horizontal, which is the maximum recommended by Universal. The Owner's Manual says the engine should hold 4-5 quarts of oil, this always puzzled me because I have never been able to remove/add more than 2.75 quarts. Don Moyer advised that the engine traps about 1.5 quarts of oil inside its various passageways. At this extreme slope, the remaining amount of oil that you can remove from or add to the crankcase is only 2.25 to 3.5 quarts. Since you cannot remove all of the dirty oil from the engine it is very important to check and change it after every 50 hours of use, OR no less than once every fall before lay-up, which ever comes first. You may also want to change the oil, let the engine run awhile to flush it out and then change it again to remove more of the contaminated oil.
Featherman Enterprises: John Featherman is back in business sellin the most common A4 maintenance parts
To Order Call: 717-432-9203
NEED HELP? For lots of FREE advice on troubleshooting or repairing your A4 engine, join the Atomic Four Mailing list at http://www.sailnet.com by sending an email to firstname.lastname@example.org
Made with a Mac!