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|Frequently Asked Technical Questions|
|Can I use regular gear lube in my "Old Merc"?|
|Mercury originally recommended a light grease in all 1961 and older 1, 2, and 4 cylinder models except the 1961 Merc 500. Grease was also recommended in the 1962 Merc 250. We still feel this is the best choice for these older motors. We carry 105 Lubriplate, which is the equivalent, in a 10 oz. tube.
For Mercs newer than this, we carry and recommend Mercury's Premium Gear Lube.
|How much is my old outboard worth?|
|This is not an easy question to answer, as it is dependent on many factors such as cosmetic condition, mechanical condition, region, rarity, etc. We are not able to offer appraisals. The best place to find information on the value of old outboards is in Peter Hunn's The Old Outboard Book Volume III.|
|I have the service manual and I've tried everything and can't get my engine to run properly. What can I do??|
Most people can't find competent professionals to work on old outboards. Shipping a motor far away for service is a poor solution. The best solution is to be able to work with someone else "hands-on." Friends who tinker with engines are the first choice. Two heads are always better than one, even if your friend doesn't know outboards. Joining the Antique Outboard Motor Club and getting to know the fine hobbyists in your area can be very helpful.
They are often willing to share their knowledge and try to help someone who has tried to help himself. Internet chat groups may also be a source of suggestions. Ask a member on the Antique Outboard Motor Club site, or post your question on John's Old Mercury site.
|I've acquired an old Merc. What should I do to get it into good running condition?|
|Digging In: Some Tips on Evaluating and Fixing Up an Old Merc by Bob Grubb
Perhaps you have recently acquired an old Merc, or are considering purchasing one. You may be wondering where to start to get it running again, or how to tell if it is even fixable at all. I've put together a list of general suggestions designed to help you evaluate a motor, and give you a general idea of what could be needed to bring it into working order.
Give it a general look-over. The ideal is a clean freshwater motor. Beware of battered or corroded motors or motors with discolored paint on the powerhead from overheating. Motors with broken or missing parts or battered fasteners from constant tinkering are also negative signs.
Check that the motor turns over and feels like it has decent compression(s).
Check the lower gear case for cracks or breaks. Check the lower gear case lube. Rusty water or no lube are very bad signs. Crank the engine over or turn the prop, and watch the end of the prop shaft for any visible run out (bent shaft.)
If, at this point, you've not found any problems you consider serious, remove the spark plugs and check for excessive internal looseness. I like to use an allen wrench to insert through the spark plug hole against the top of the piston. Turn the flywheel so the piston is about mid-travel. At this point, try moving the flywheel slightly back and forth to try to detect lost motion between the crankshaft and the piston. Any significant movement of the flywheel without corresponding movement of the piston means disassembling the engine to find the looseness. It can be either in the piston pin or crank pin or both. Repeat this procedure on all cylinders.
Try moving the flywheel sideways. There should be no noticeable looseness in this direction. Check up and down, there should be some end play, but generally not more than .015".
Next, turn the motor over at a slow cranking pace and you should hear a soft pop from the spark plug hole each time the piston goes down and opens the intake port. This is a necessary indication that you have crankcase compression. Badly worn bearings, bad crankshaft seals, or leaking reed valves are causes of not having this. Another possible cause is, of course, little or no compression at all. I find gauges vary, but generally the smallest models should have 80 pounds or more, medium size models 100 or more, and many larger models 120 lbs. or more. Any engine with two or more cylinders should have similar compression on all cylinders.
If poor compression is your only internal problem, you may be able to restore the motor without tearing the motor down by using an engine cleaner (available from us or your local dealer.) This can only help if the problem is caused by piston rings that are stuck from carbon deposits.
If anywhere along the line the engine has failed a test, it must be dug into to correct the problem or laid aside as a source of parts for other engines. We are not out to ruin any equipment. On the other hand we find it best to not unnecessarily tear down power heads. Many times, unnecessary honing and poor cleanup results in a motor that is more "worn out" than it was before.
We recommend in general replacing the upper and lower crankshaft seals on the old Mercs, where this can be done without completely disassembling the powerhead.
The conventional magneto or battery ignition systems used mid to late 60's and before should be capable of jumping a 1/4" spark gap in the open air. Weaker spark than this usually means that condensers or coils or both need replacement.
Generally, fuel pumps should be rebuilt, replacing at least the diaphragm. Carburetors usually need disassembly and cleaning to remove old gas residue and debris.
Water pump impellers should be checked by disassembly and usually will need to be replaced.
Lower gear case sealing was originally not up to today's standards and usually has only gotten much worse over time. You should keep close tabs on the gear lube. (I check my own motors after each use.) Making these units seal as well as possible usually involves repairs to the shafts, as well as seal replacement.
Hopefully, following these guidelines will provide a good performing engine (or help you to decide that your engine is not a good candidate for restoration.)
|I've become interested in old outboards in general. Where can I get some more information?|
|The Old Outboard Book by Peter Hunn is the answer (part #OOB3). It's a terrific basic information source. You may also be interested in checking out the Antique Outboard Motor Club.|
|I've got an old Merc and my dealer can't help me keep it going. I want to work on it myself. Where do I start?|
|You should start by purchasing a parts manual and service manual and possibly an owners manual for the engine. Familiarize yourself with their contents. As you determine your needs, we will try to help you from there. You may also wish to read "Digging In: Some Tips on Evaluating and Fixing Up an Old Merc" by Bob Grubb.|
|Should lead additives be used with old outboards?|
|NO! Lead was never needed or desirable in any 2 cycle engine. The oil that is mixed with the gas provides all the needed lubrication.|
|What advice can you give for winterizing my "Old Merc"?|
|There are essentially two forces your engine needs to be protected from during the off-season. The first is cold temperatures (and the possibility of freeze damage) and the second is any possible side effects resulting from a period of disuse. Fortunately the necessary precautions are fairly easy and straightforward.
Not everyone will have the option of storing boats and motors indoors for protection from the elements. For the rest of us, some simple steps can help avoid damage and prolong engine life. First, be certain no water is present in the gearcase before freezing temperatures arrive. Not only will water left in the gearcase cause rusting, but the expansive force of freezing water is strong enough to crack gear cases. This is a good time to change the gear lube completely (see gear lube info, above.)
Covering boat and motor for storage outdoors is a good idea. Shrink-wrapping probably offers the best protection for several reasons. Its tight, taut fit won't sag and puddle water, and will shed snow and ice easily. Rain proof vents are added to shrink wrap so that any remaining moisture can leave and the boat can "breathe." Conventional canvas-type covers should always be removed before shrink-wrapping and stored separately in a dry place. Mildew prevention products should be placed under the cover, according to package directions. Any time a boat is stored out of water it should be with bow slightly elevated and drain plug out so that any moisture that finds its way in can drain out.
Engine disuse is a second factor that can easily be prepared for. It is recommended that fuel be stabilized with a product such as CRC Fuel Stabilizer if the engine will not be used for one month or more. Add stabilizer to your fuel tank according to package instructions to keep fuel fresh for next season and protect against gum & resin build-up. Run the engine so that the product will be drawn into the engine fuel system and provide protection to the carb(s), fuel pump(s), and fuel lines. (Remember never to run the engine without adequate cooling water supply. Running your engine dry for even a minute can destroy your water pump and leave you vulnerable to overheating. If you want to run your outboard in the driveway, use a flushing adapter designed for running the engine with a hose.) A storage fogging oil such as Mercury's Storage Seal should also be used during the final run of the season to protect the engine internally from rust and corrosion. With engine running (after allowing stabilized fuel to run thru engine), disconnect fuel line from fuel tank. Spray fogging oil into the carburetor(s) until the engine stalls. For non-running engines, remove the spark plugs and spray into each hole, then turn the engine over several times by the starter and replace the spark plugs.
For additional rust and corrosion protection, spray the engine externally with Corrosion Guard. Linkages and fittings can be lubricated with Mercury 2-4-C lube. It is a good idea to remove the prop at this time and grease the propshaft with 2-4-C.
Following these simple steps will help insure that your engine lasts for many seasons to come.
Modern fuel injected outboards and inboard/outboard (sterndrives) will need additional winterizing steps. See your dealer.
|What are the implications of using gasoline with Ethanol?|
Mercury Marine’s View of Ethanol
|What is the proper fuel to oil ratio for my old outboard?|
|The currently preferred fuel is the mid grade (89 octane). All post World War II non-racing Mercs (except KB-4's) can operate safely on a 50 to 1 fuel/oil mixture using modern TCW 3 oil. Racing models and the KB-4's should not be run leaner than 25 to 1.|