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1973 johnson 135hp

dnspiveral

New member
engine is lost spark on water

engine is lost spark on water after running 45min
pulled boat out and got it home and engine runs fine
put it back in the water and runs 30 min and dies
get it out and home and it runs again
 
"The stator under the flywheel

"The stator under the flywheel (Green Ring) is the beginning of both the charging and ignition system. Inspect it for cracks and a oozing/dripping of a stickly like substance down on the timer base and powerhead.

Should the above condition exist, the AC voltage output to the powerpack may be fine when cold, but when that stator heats up, that AC voltage drops down to a point whereas the powerpack cannot be energized, resulting in weak or no ignition. (Replace the stator if damaged as above).

It's unusual for that type stator to fail but it does happen and usually the cause of that stator failure is due to a shorted damaged rectifier (see the following).

(Small Rectifier Description & Location)
(J. Reeves)

On most 3,4,6 cylinder engines, the small rectifier is located on the starboard (right) side of the engine just in front of the engines electrical wiring strip. There are a few older V4 engines that have the wiring strip on the rear portion of the engine and the rectifier would be located just under that terminal strip. The smaller horsepower engines usually have the rectifier located on the starboard side of the powerhead close to the carburetor area.

The rectifier appears to be a round object approximately one inch (1") in diameter and also about one inch (1") high. The base of it is sort of triangular in appearance and is attached to the engine with two (2) screws/bolts..... usually one screw/bolt is larger than the other. The rectifier, depending on which one your engine uses, will have either:

One Red wire, one Yellow wire, and one Yellow/Gray wire, or One Red wire, and two Yellow wires.

Note that either of the above rectifiers could have a fourth wire which would be Yellow/Blue

********************
(Small Rectifier Test)
(J. Reeves)

Remove the rectifier wires from the terminal block. Using a ohm meter, connect the black lead of the ohm meter to the rectifier base (ground), then one by one, connect the red lead of the ohm meter to the yellow, yellow/gray, then the red wire (some rectifiers may also have a fourth yellow/blue wire. If so connect to that also). Now, reverse the ohm meter leads and check those same wires again. You should get a reading in one direction, and none at all in the other direction.

Now, connect the black lead of the ohm meter to the red wire. One by one, connect the red lead of the ohm meter to the yellow, yellow/gray, and if present, the yellow/blue wire. Then reverse the leads, checking the wires again. Once more, you should get a reading in one direction and none in the other.

Note that the reading obtained from the red rectifier wire will be lower then what is obtained from the other wires.

Any deviation from the "Reading", "No Reading" as above indicates a faulty rectifier. Note that a rectifier will not tolerate reverse polarity. Simply touching the battery with the cables in the reverse order or hooking up a battery charger backwards will blow the diodes in the rectifier assy immediately.

If all of the above checks out okay, remove the black/yellow wire from the powerpack and retest the engine. If this cures the problem, the usual cause is a intermitently shorted ignition switch, in which case, replace it.

Lastly, your ignition may be fine and in which case the engine may be encountering a fuel restriction which is usually a sticking anti siphon valve as follows.

(Fuel Anti Siphon Valve)
(J. Reeves)

Many of the later OMC V/6 engines incorporate a fuel restriction warning via a vacuum device attached to the powerhead. If the engine overheats, or if you have a fuel restriction, the warning is the same.... a steady constant beep.

NOTE... Only the V/6 & V/8 engines have the above "Fuel Restriction Warning". The warning horn will not sound on the other models.

The fact that a engine is not overheating, but the warning horn sounds off with a constant steady beep, and that the rpms drop drastically would indicate that the engine is starving for fuel due to a fuel restriction. Check the built in fuel tank where the rubber fuel line attaches to the tank fitting. That fitting is in all probability a "Anti Siphon" valve which is notorious for sticking in a semi closed position. It will be aluminum, about 2" long, and the insides of it will consist of a spring, a ball, and a ball seat. If this valve exists, remove it, knock out those inner components which will convert it to a straight through fitting, then re-install it. Hopefully that cures the problem.

The above procedure will cure a restriction problem with the anti siphon valve as stated. BUT, it may also allow fuel to drain backwards to the fuel tank when the engine is not running (siphoning backwards) due to the fact that the carburetors/fuel pump etc are higher than the fuel tank. This condition is not an absolute as the valves in the fuel primer bulb usually prevent this backwards siphoning problem. However.... if this does take place, the cure would be to install a new anti siphon valve.

Let us know what you find.

When time permits, visit my store at: http://stores.ebay.com/Evinrude-Johnson-Outboard-Parts-etc?refid=store"
 
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