Johnson

Johnson, Evinrude, OMC, outboard motor, outboard motor repair, outboard troubleshooting, 9.9, 15 hp, year of manufacture, water pump, carburetor, long shaft, 15 hp conversion, sailmaster

In this article I will not deal with any specific make of manufacture or model, but just what to look for & in close proximity of & what order to look at. Many times you enter into a situation where someone is posting information on a on-line message board, there seems to be a lot taken for granted as to "Existing General Knowledge" as related to outboard engine repair. In this article I will try to explain as much as possible in very simple language, however this is not possible without using the proper terminology. We will be dealing primarily with small 2 cycle motors up to about 10hp here, but the principal is the same for all sizes.

First off let us assume that you have at least a small amount of mechanical knowledge. If you do not know the difference of a #2 Phillips screwdriver from a 8" adjustable spanner (Crescent) wrench, & you are not one of those persons who should not be left alone with a pencil sharpener or even sharp knife. If you do not have the ability to read & at least comprehend even the least bit if information, then you probably had better take your problem to a professional & make a deposit into his bank account for his experience. You can invest in outboard repair manuals & books, spend some time digesting what they are saying as to what they really mean by looking at your motor & do your own wrenching trial & error repairs. I will however 98% guarantee that you will not have instant gratification the first time around.

Here it is: Let us assume that know nothing at all about the motor staring at you. First thing I would do is to pull the starter rope to see if the motor is not seized or frozen up in some manner. If so, it could be a rusted, blown or seized piston, or even a frozen gearbox. Any of the above, would indicate that way more diagnostic & repair work would be required than a simple (or not so simple) just putting new gas in & getting it started situation. This would be the first of a check-off list as to this motor possibly being a candidate for the junk pile.

Try to find out some sort of history about it if at all possible. Now also take into consideration the source of your information. If the person just happens to be selling it, many times, they stretch the truth more than as little (remember they could also be fishermen). If you can come up with any information at all, this may help you instead of doing all your own detective work. When I say detective work, it is just that, you need to know what requirements are to make the engine run & be able to go thru a check-list. One small overlooked item may be the key to getting your motor to function. And remember just because you found pieces or parts installed in a certain way does not mean that this is the proper installation if someone has had a wrench on it before.

Inspect the motor, the general overall condition can give you some indication as what to expect. Has it been USED or has it been ABUSED? There is a distinct difference here. Are any parts missing? Can you see any new gasket sealer at some parts joints of the block or under the head? Has it been recently repainted? The above two are indicative that someone has been working on it, WHY is the question you need to ask now that you have been delegated to get it running since apparently they could not? Here we are making an assumption that the motor is not seized up in any manner be it pistons or gearcase. And all that is needed is much Tender Loving Care to get it purring again.

How Old is It ? : If the above motor happens to be a pre-WWII motor, or even a few years later, like up to mid 1960s, parts may well not be easy to find. You will most likely need electronics, like coils, possible points (however most points can be cleaned up), or condensers (condensers rarely fail however).

Requirements / Methodology: ANY internal combustion engine has NEEDS 3 simple but main requirements to run, they are Spark, Fuel & Compression.

All the above being said, there may need to be some fine tuning of the first two to make it run in a manner where it can be used efficiently.

Spark is one of the main requirements for an engine to run. The older motors will have a Magneto type ignition. In these, spark is generated by the flywheel magnets rotating around a coil of some sort. This generates electricity, that electricity is transferred to a condenser & then to a set of points. From the points/condenser/coil, the electricity is magnified & intensified then sent thru a insulated wire to the spark plug which when the motor is timed right & the compression of the upcoming piston compresses the fuel, the spark plug creates a intense electrical spark (fires) because of the points opening, igniting the compressed fuel, creating combustion, starting the motor running.

Motors newer than about 1978 (depending on manufacturer & model) moved onto electronic ignition, eliminating the points, using a new Capacitor Discharge system & a power-pack. This system produces a stronger spark & usually a smoother idle/trolling speed. However you may see some of the smaller 2 to 4 hp newer motors still using the magneto ignition, probably because of the expense of the electronics.

We will be dealing here mostly with non electric start motors, simply because that narrows down many other things we will not need to look at. Any electric start motor should be able to be started using a rope, (unless the motor is so large you can not physically pull it over). And even if it has a electric start, all that I am aware of do not need the battery to run the motor, just for it to utilize the electric starter & generate electricity to supply power to any electronics you have aboard. That said, some of the newer motors, even the 4 stroke Yamaha T8 electric start/power tilt does not have a manual starter.

(1) Spark: If you are working on a older motor that uses the Magneto type ignition, if you are not getting any spark to the spark plugs, you need to back up, pull the flywheel & check the internals for loose or broken wires. Pull the points, clean them with lacquer thinner, clean the contacts with a point file, reinstall & adjust them (usually to .020"). Check the wires leading to & from the coils & condenser for looseness. If the insulation on the coils are cracked or peeling off you can be pretty well assured that they are bad. However you can check if the coils are good by using a simple multi-meter which usually sells for about $20. But it has to have a Ohm resistance scale on it which you need to set in it's highest setting. With the meter set at Ohms, short out the black & red wire probes, the needle should climb, there usually is an adjustment knob to calibrate this reading when shorted out like this, if so make it read all the way. Now the coils have a primary & secondary winding. The primary winding will have the heavier wire, using the probes, ground out the black & touch the outgoing wire to the points, you should not get a reading. Now leave the black probe on the ground & with the red, touch the wire going to the spark plug. If it reads near .6 the coil should be OK.

Condensers are not as easy to test unless you have a special tester, however you may be able to take them to a automotive supply store & have them test them. This test places a charge into the condenser & then registers how fast it disperses this charge. Each motor is designed for a specific condenser output, but they should be able to at least come up with a guestimate if the condenser number is missing. Condensers on the other hand, if they are still available are rather inexpensive, however some of the imported ones longevity is not as reliable as the older ones.

In talking to an experienced motorcycle mechanic that was well accustomed to seeing older magneto type ignition bikes, he related that (1) most condensers are replaced simply because the cost is low as compared to labor for trouble shooting the electronics later if it doesn't run. (2) His method of telling if a condenser is bad, is look at the points, if they are pitted badly, it is because of a failing condenser. However if the points look evenly worn, just clean them with lacquer thinner, drag non-waxed paper like a brown paper bag thru the contacts a few times, adjust them & 99.9% of the time it will run great.

The spark plugs are the thing that is screwed into the head of the motor that actually creates the fire to ignite the fuel. They consist of a metal threaded portion with a ceramic insulator that has a metal center that the insulated wire from the coil attaches to. They need to be in good enough condition to transfer the spark from the coils to the combustion chamber & ignite the fuel. Also you have to use the right spark plug, not just any old plug will do. Spark plugs are made in different size threads with different thread lengths, called reach & in different heat ranges. It would be very detrimental to a piston if you tried to use a 1/2" long reach in a motor that was designed for 3/8". Plus the piston surely will bottom out against the plug blocking any further movement making the motor impossible to pull start with the starter rope.

One simple way to check if the plug is firing is to remove the, or all spark plugs, (makes for easier cranking). Reinsert one plug into the spark plug wiring boot & ground the threaded end of the plug to a bare place on the motor, (usually a head or thermostat housing bolt). Pull the starter rope while watching the location of the electrode on the spark plug, (many times here is where a helper comes in handy & do it in a shaded area). Change to the other spark plug wire if a 2 cylinder & redo the above test to verify it is also working or not.

The spark should arc from the over-arm electrode to the center post of the spark plug in a white or blueish color. If the color is orangish, there is something weak in the system. It may run, but may well be hard starting.

It is recommended that you build or purchase a spark tester. These can be set for specific distances, which in turn will give you some indication of the of the performance of the ignition system. If the spark does not jump the suggested distance or is the wrong color, you need to do something about it.

The recommended spark gap for testing does vary with different ignition systems as follows.

Standard magneto ignition = 1/4" gap

Battery Capacitance Ignition = 3/8" gap

Capacitor Discharge Ignition = 7/16" to 1/2" gap

(1A) Spark Timing: Occasionally you will find that the flywheel key has been sheared allowing the fly wheel to slip past it's intended location. If this is the case, the spark timing will not be correct in that the flywheel magnets will not be in the proper location on the crankshaft to give the spark off the coils to the spark plugs at the proper time & it will not even sputter.

(1B) Spark Timing: The twist grip throttle handle has to be aligned so that the timing plate under the flywheel is somewhere close to the position where the motor WILL start. That is why the twist grip throttle has marks on it lining up with words like slow, start & fast on the handle shaft. If in doubt, & there may be some slack in the handle linkage, move the twist grip to the faster position than slower.

It is even possible for the motor to "kick back" the rope starter when you try to start it. If this is the case, check your flywheel key, could be it is sheared and allowing the flywheel to slip on the shaft, which will put your engine out of time.

(1C) Spark Timing: The bulk of these old motors may be made before about the mid 1970s where the ignition is a straight magneto setup with points and condensers, compared to the newer electronic ignition. The flywheel will usually have to be removed to work on this ignition. There is a set of points & a condenser for each cylinder. The points need to be set at the manufacturers recommended gap which is usually .020". The point setting is usually stamped on the armature plate under the flywheel, & or on the inside of the flywheel, so if you remove the flywheel you can see this setting. These flywheel pullers do not pull from the outer edge, but from 3 bolts screwed into holes in the top of the flywheel.

All outboard motor crankshafts have a taper on the top end below the threads that corresponds to the same internal taper of the flywheel. In order to have the magnets align properly to provide electrical power to the points & or coils there is a keyway cut into the crankshaft in precisely the right location that also has to fit the flywheel into it's location.

Some keys are just a rectangular piece of steel about 3/16" square, while others are a 1/2 moon shaped (or Woodruff key) & about 5/8" across the widest part. For the Woodruffs, the radiused is positioned into a radiused slot in the crankshaft. These keys have to be in their respective slots & deep enough for the flywheel's slot to mate & be able to be tightened down. If the Woodruff key is rotated slightly, (up or down) the flywheel may not seat down tight on the taper when the flywheel nut is tightened. You may have to remove the key, & remove any burrs on it, replace it in the crankshaft slot so that the slot in flywheel will slide down & align otherwise the flywheel will not be seated & wobble if rotated. These keys are made of a soft metal so that they will shear if the motor happens to come to a sudden stop as to not bend or ruin the crankshaft.

Illustration out of an OMC manual showing the key in the crankshaft

In setting these points, advance the twist grip throttle to FAST as far as it will go. The #1 piston should be at Top Dead Center. This can be verified by pulling #1 (the TOP) spark plug & by using a flashlight, rotate the crankshaft clockwise until you can see the piston come up, go slowly & backtrack, then rotate it clockwise again to where it is at the top of it's movement This is now Top Dead Center. There may be the word TOP or SET on the timing cam ring that is on the crankshaft protruding above the timing plate. Your points rub bar should now be at or near the TOP location. Without changing the twist grip location, move the crankshaft to the SET position. Set the #1 points (usually on the RH side of the motor) with a feeler gage at .020, (if that is the setting so marked) rotate the crankshaft 180 degrees if a 2 cylinder & again with the rub bar at SET, repeat the setting for #2 piston.

Sometimes on the older & smaller motors there will not be any TOP or SET markings. If this is the case, then with the piston in the furthest up position, rotate the timing plate until the cam is in it's largest location holding the points apart. Set the points at this location.

If the motor has sat for a while the points may have gotten oxidized. This can be usually remedied by running a point file (yes they still sell them at automotive supply stores) thru the point openings to freshen up the contact metal. A normal file is too thick & usually not hard enough to touch the harder point surfaces. If you do not have a point file, then some fine emery cloth pulled thru the points may remove some of the oxidation.

If you encounter hard starting on this series of motors, you could try opening up the points a bit. Some "Old Timer Mechanics" word is that to make those ignitions work a little better, these mechanics would open up the points to where it ran better, even about .030" as the coils lost some of their power. This older ignition using condensers, if they start to break down internally, the motor can start & run for a while, but when things warm up, the condensers & or coils can begin to short out internally & the motor may die. You can crank until you are blue in the face but it refuses to start. Let it set for an hour to let these components to cool down, contract & eliminate the internal shorting. It MAY then restart. Time to change condensers or even coils.

(1D) Spark, or Lack of It If you finally get it to run, it is a 2 cylinder but it is laboring & or has no power. You can very likely have a motor that is running on only 1 cylinder if it is a twin. Here for some reason you have a problem, usually somewhere in the electrical system. A spark plug is bad, the wires have a bad connection somewhere, or the ground wire somewhere has corrosion under it, even a bad coil or power-pack. This should have been caught in #1 of this section. If you get here then the simplest test is to, while it is running, pull one spark plug wire at a time. If it does not make any difference in the running when you say pull the top (#1) plug wire, that will be the dead one. If you reconnect it & then pull the bottom (#2) wire it will die. BINGO you have found the culprit. Now only to find out why.

(2) Fuel: The other basic is fuel. It needs to usually be 87 octane gasoline, AND be clean of debris, & NOT old or stale. Stale meaning sat for years & deteriorated with a foul varnish smell when the cap is removed.

If you are trying to start a motor that has sat for a while & try to squirt fuel into the spark plug holes & or carburetor, this is the place NOT for "if a little is good then a lot is better". If you get to much in, the fuel will drown out the spark plug electrodes & you will not get the spark plugs to fire.

The fuel tank HAS to be vented in order for the fuel pump to suck the fuel into the motor. Some of the older manufacturers metal gas tanks may have a internal automatic vent system. Others require that you slightly unscrew a vent screw, usually on the filler cap. If this vent is not loosened, the motor may start, but will soon die when it can not suck new fuel into the carburetor.

Check the fuel tank for varnish. This will be a gummy or hard deposit left after the gasoline evaporated & has dried up. Just pouring new fuel into an old contaminated tank is asking for trouble by sucking dirty fuel into the carburetor. One thing I have done in the past for this condition is to purchase a pint of Xylol or Xylene (same product), which is a highly potent paint solvent/thinner works better, cleans the inner tank very well. A quart costs about $6.00, just pour in enough to cover the hardened residue. Next a large hand full of ceramic tumbling stones were added, (a substitute would be washed pea gravel) replace the cap & shake the tank in all directions for a few minutes each time I pass by it in the shop. Note that some internal hardened residue may extend up on the insides also, if so, lay the tank on it's sides occasionally to soak as well. Let it set & shake for as long as it takes to soften the debris. Overnight you will see things start to happen. Inspect with a flashlight, keep shaking. Flush it out, repeat if needed.

The fuel lines may also need to be replaced or at least cleaned. A fuel filter may be needed in the line before the carburetor. The small plastic fuel filters used on lawn mowers would be one to look at.

Most of the motors made before mid 1960s used bronze bearings in the connecting rods. On these motors the fuel needs to a richer oil ratio of 25 to 1 otherwise the motor may be under lubricated & seize up. NOT GOOD. However using this rich a fuel/oil mixture may contribute to fouled spark plugs more often than the later motors that recommend a lesser amount like 50 to 1. But do you want a motor that is running or blown up?

(2A) Delivery of the fuel: This is where things could start getting complicated, as the fuel needs to be transferred from the fuel tank, to the fuel pump, then into the carburetor.

If you happen to be working on a smaller motor that uses an internal tank on the motor, life can be simpler as you will not have a fuel pump or all the associated fittings & neoprene lines.

Anywhere there is a connection in a fitting or rubber tube is a potential air leak up to the fuel pump, this will break the vacuum from the tank to the fuel pump. Also the fuel pump will have to have some means of activation. This is usually thru a small fitting or passageway into the crankcase cavity. In operation, being a 2 stroke motor, the crankcase, on the backstroke, or the intake manifold creates a osculating vacuum/pumping action, thereby giving a pulsation between sucking & exhaust. This osculating action of pressure/vacuum operates the fuel pump's internal diaphragm. Once the fuel is sucked into the fuel pump there are small check valves that do not allow it to be reversed, which now push the fuel into the carburetor. There may be a fuel strainer of some type that has to be clean & functioning.

(2B) Once the fuel is at the fuel pump it must then be transferred to the carburetor. A leak here may not be as critical as on the other side, BUT it could also create a fire hazard.

(2C) The carburetor needs to be clean & adjusted somewhere near properly for it to start. After it starts, warms up & is running at a near idle, the idle adjustment screw may need final adjustment. Cleaning the carburetor does not mean spraying carburetor cleaner or Sea Foam into the throat, or even doing this while it is running. The carburetor really needs to be removed & physically cleaned & or soaked in carburetor cleaner.

(3) Compression: The piston rings & cylinder bore have to be good enough condition to suck the fuel from the carburetor & into the motor. Most small motors up to 50hp will be a 1 or 2 cylinder & the compression is not usually high as compared to a automotive vehicle. If it is a twin, the two cylinders do need to be close in compression, meaning one can not be 85# while the other is at 35# to operate effectively. This would indicate the low one may well have a blown head-gasket, broken rings, or a scored cylinder, even a broken ring gland in a piston, any of which would seriously hamper the starting, much less running of a motor.

However if the motor you are working on has set for some time, which will dry out the internal cylinder walls, & you pulling it over with a rope type starter, your compression reading will normally be lower than if it was running right up to the time you acquired it.

See #7 at the end of this article as to something to do after you get it running.

(4) Try to Start it: With these tests performed, try to start the motor by opening the fuel shut off or pumping the fuel line bulb (if it has a remote tank) until the pump bulb becomes hard, indicating the carburetor bowl is full & the float valve has stopped any more fuel flow into the carburetor. When pumping the bulb, the bulb itself needs to be pointing vertically until it becomes hard. This is because internally in the bulb is a inlet & a outlet check valve, these utilize very weak springs so that when during the normal running of the motor, fuel will flow with minimal restrictions. But on the initial pumping if you leave it horizontal, the check valves may not function well enough to pump up a dry carburetor. Once the bulb is hard, do not keep trying as you may just be pumping raw fuel out a carburetor overflow.

Pull the starter rope as vigorously as you can. If it does not show some form life within the first 6 pulls or so, you may have to pull the spark plugs & squirt a couple of squirts of mixed fuel into the spark plug holes. Try pulling again. If you do not get it to fire, you will have to go over the above items AGAIN. Some people use starting fluid for this, but do not overdo the starting fluid as it does not have any lubrication & if continued usage it could damage the rings/cylinder walls because of lack of lubrication. What you are trying to determine here is if the fuel pump is malfunctioning. Ideally you should be squirting the fuel mix directly into the carburetor or it's breather unit.

These old motors will usually need to be ran with the choke partly out until they warm up. Each motor is unique to itself, so you may have to find a sweet spot that it likes until it warms up.

OK, now you have it running. Is it spraying water out the "pee hole" or a watery mist out the back side of the upper cowling if it is this early type pre 1977 or so? If not, watch for the motor overheating. The pee hole may just be plugged. The easiest location to check this would be if the top of the block under & behind the flywheel, if it gets so hot you can not touch for longer than a few seconds or the paint smells like it is burning. NO COOLING WATER GOING THRU THE MOTOR, SHUT IT DOWN ASAP. More on this problem listed farther below under water pump repair.

You probably may need to adjust the carburetor idle needle valve knob because someone may have already tried. Most of these have some sort of a lever or rotating knob for this idle adjustment. When you finally get it set where you want, mark this location somehow for future reference.

If the motor is to be used for trolling, you may have to fine adjust this idle (or slow speed knob) to a position where the motor runs smooth enough for intended purposes. Make this adjustment 1/4 turn at a time & let it run for a minute to allow the fuel in the carburetor to be metered by the new adjustment. Usually screwing this knob in (clockwise) lessens the amount of fuel delivered to the engine. When you reach a point that the engine lugs down & dies, back it up slightly & you should be there. However if in your adjustment if you go counterclockwise & the motor coughs & dies, this is usually an indication it is too rich & go the other way.

Some older carburetors also have a high speed adjustment knob. This can only be adjusted in a test tank or on the boat when the motor is running at full throttle. By adjusting it you will soon be able to tell if the motor is running faster or slower & be able to select the proper setting required.

(5) Repair Water Pump: OK, this is not really starting related, but you may not be able to run it for long if the water pump is inoperable. You may have found that no cooling water was coming out of the motor. A few older motors were air cooled, usually they will have cooling fins on the powerhead. Even some of these air cooled motors will have some form of water cooling to keep from burning the paint off the exhaust housing.

(6) Lower Unit or Gearbox: All motors will have a lower unit or gearbox that transmits vertical power from the motor to horizontal power to the propeller. These lower units houses the gearbox so it can be separated from the mid-section or "leg", by a few bolts. Finding a replacement water pump impeller may be a problem on some of the older motors that were sold by mail order stores.

(7) Decarb: Chances are good if the motor has set for any length of time & you may not know anything about it, that the rings may have become stuck in the piston. This can hamper the running of the motor because of lower compression. The easiest way to help here would be to purchase a commercial de-carbonizing liquid that is ran thru the gas & / or squirted into the pistons, let set & then ran. One that is usually available at automotive parts stores is SeaFoam. This stuff softens the carbon buildup & when the motor is then ran it blows this now softened carbon out the exhaust & many times gives the motor a new lease on life.

One method of decarbing used by many is to mix a strong mixture of SeaFoam into a 1/2 gallon of mixed fuel, make up a small fuel tank with fitting to the motor if applicable & run the motor at a medium speed let most of the fuel be consumed & shut the motor off. Pull the spark plugs & squirt more SeaFoam directly into the spark plug holes. Let the motor set for 20 minutes, & then start it up. If you have carbon internally the motor will burn this loosened carbon which will SMOKE considerably.

(8) Recap: This article is mainly geared to getting your motor running. Once it is running, there can be many other things that may be needed to be repaired or adjusted to make it function properly.

The above items are just a general outline as to what is needed. Entire books are written on the subject & for each make & individual model of engines, so it is impossible to cover all that you may encounter here. There are many tricks in taking motors apart that will not be written down. Johnson & Evinrude motors are designed by a whole different bunch of engineers than Mercury, so even thou they all propel your boat across the water, they can be very different in internal design. Some motor designs are easier to work on than others & the engineers at Mercury apparently drink a different water.