I know people keep asking about this particular distributor system. I have been chasing problems all over my engine and I believe the end is in sight.
When the motor is cold it's start, idle, roll on, and run WOT all great. When it gets good and warm it'll run WOT just fine but has trouble idling and getting off idle. It also doesn't like low idle when it's warm either.
I have rebuilt the carbs, replaced the rectifier, I have an new battery, I cleaned the points (and gapped at .010), checked all the connections (really, all of them), replaced the plugs and wires (Champion QL77JC4's), and cleaned the distributor connections.
I assume the distributor and rotor can "weaken" over time. I don't think they offer replacements for it (distributor and rotor) anymore. Can it be reconditioned? I wouldn't mind paying for the new distributor and rotor if I could find one.
F_R here. The coils that I keep harping on are the ones on the classic era twin cylinder motors. This is a different animal. That's not to say that the coil can't be the problem here. Truthfully, I am not really in love with the ignition system on this motor. I do think the distributor cap is a poor design and had trouble with them even when new. Trouble is, I've replaced caps and rotors and it really didn't seem to help. When the motors work, they work great. When they don't work, they will drive you crazy. I wish I had the answer but I'll defer to somebody else here. BTW, on this ignition system I had the best luck with L77JC4 (not Q) gapped at .040. Your luck may vary.
Thanks guys, I have been out of town. Interesting F_R, since the distributor and rotor are hard to find and expensive I'd rather not buy them unless I know for sure. Most of my experience comes from small engines, motorcycles, and cars. That said I would agree this ignition system leaves a bit to be desired (especially if you subscribe to a less is more ideology).
I'll get the non-Q Champions since they're cheap and can't hurt. Actually changing the plugs and wires has been a slow but steady progression in the right direction.
What do you know about reconditioning the distributor? Could a new magnetic tip on the rotor make a difference? I do not understand the relationship of the rotor to the distributor. When the magnet of the rotor passes the spots corresponding to the plug wires does it induce current to flow to that plug wire or what? ...is that a magnet on the rotor?
By the way CharlieB, F_R was referring to the spark plug gap not point gap. You were correct about the point gap, .010 for old and .012 for new, thanks.
The distributor in the ignition system of an internal combustion engine routes high voltage from the ignition coil to the spark plugs in the correct firing order. It consists of a rotating arm or rotor inside the distributor cap, on top of the distributor shaft, but insulated from it and the body of the vehicle ("earth"). The metal part of the rotor contacts the central high voltage cable from the coil via a spring loaded carbon brush. The metal part of the rotor arm passes close to (but does not touch) the output contacts which connect via high tension cables to the spark plug of each cylinder. As the rotor spins within the distributor, electrical current is able to jump the small gaps created between the rotor arm and the contacts due to the high voltage created by the ignition coil.
The above is a correct description. To put it another way, the rotor receives voltage from the coil and points to the correct contact which is connected to the wire going to the cylinder that is in line to fire and the spark jumps the small gap, goes through the wire to the spark plug and jumps that gap too.
I'm only commenting to say that the rotor is not a magnetic device. It merely acts as a switch or connection, so to speak.
Dirt, moisture or contamination allows the spark to jump off in some direction other than where it is supposed to go. A common source of contamination in those motors is the anti-reverse cut out ring. It is supposed to be very lightly lubricated where it rides on the crankshaft (EP grease). Lack of lubrication causes it to wear and tiny metallic dust particles get all over everything causing an electrical leakage path.
If that is the case then I have to take my distributor apart again because I do not remember seeing the spots on the distributor where the current could jump to from the rotor. Obviously they are there but I'm sure attention can be paid to their condition and cleanliness. Thanks guys, I'm gonna get 'er!!!
D'OH!!! Here's a bit of advice for someone who is mechanically inclined but doesn't know all of the out's and in's of older generation outboard motors. CLEAN EVERYTHING!
It isn't easy to see where my distributor and rotor cross paths because it's up underneath the top of the distributor. In this case there was "buildup" at the point the spark jumps from the rotor to the distributor. Needless to say it is important for electrical contacts to be clean if you desire current to flow unabated.
I can't say whether or not this will be the end to my 1969 Evinrude 55hp woes but it is another step in the right direction.
P.S. This forum has been a very valuable tool and has enabled me to afford owning a boat. I can not afford to pay a mechanic to figure out all of this for me (albeit the mechanic might be able to do so more quickly). Plus I gain the experience necessary to troubleshoot problems that might arise on the water. Specifically thanks to you who have taken the time to answer my questions.
Assuming that you've rebuilt the carburetors correctly, they may be out of adjustment..........
(Carburetor Adjustment - Single S/S Adjustable Needle Valve)
Initial setting is: Slow speed = seat gently, then open 1-1/2 turns.
Start engine and set the rpms to where it just stays running. In segments of 1/8 turns, start to turn the S/S needle valve in. Wait a few seconds for the engine to respond. As you turn the valve in, the rpms will increase. Lower the rpms again to where the engine will just stay running.
Eventually you'll hit the point where the engine wants to die out or it will spit back (sounds like a mild backfire). At that point, back out the valve 1/4 turn. Within that 1/4 turn, you'll find the smoothest slow speed setting.
Note: As a final double check setting of the slow speed valve(s), if the engine has more than one carburetor, do not attempt to gradually adjust all of the valves/carburetors at the same time. Do one at a time until you hit the above response (die out or spit back), then go on to the next valve/carburetor. It may be necessary to back out "all" of the slow speed adjustable needle valves 1/8 turn before doing this final adjustment due to the fact that one of the valves might be initially set ever so slightly lean.
When you have finished the above adjustment, you will have no reason to move them again unless the carburetor fouls/gums up from sitting, in which case you would be required to remove, clean, and rebuild the carburetor anyway.
And the point setting is quite critical.............
(Point Setting Of Battery Capacitance Discharge
( Ignition Models - 1968 thru 1972)
(Some have points - Some do not)
The points must be set to .010 but no wider than .010..... BUT in some instances due to a possible slight inaccurately machined crankshaft lobe or a slight offset of one set of points, a setting slightly less than .010 would be required as follows.
Whether the crankshaft has two or three lobes, when setting the points, check the setting of the points on each individual lobe by rotating the crankshaft by hand.
You may find that setting one set of points to .010 on one lobe, then turning the crankshaft to the next lobe, the gap measures .011 or .012 (too wide). This is where you would need to close that gap down to the required .010. A gap too wide can result in a ignition miss when throttle is applied.
Bottom line, pertaining to the point setting at the various lobe locations____ .010, .010, .009, is okay____ .010, .010, .011 is not!
(Carburetor Throttle Cam Roller)
First, if the engine has more than one carburetor, make sure that the linkages between the carburetors are synchronized. That is the linkages are such that all butterflies open and close at the same time. If , at idle, one butterfly is slightly open and the others closed, weird happenings will occur.
The carburetor throttle roller, when contacted by the cam that slides against it, causes the throttle butterflies to open and close. The cam that slides against the roller has a scribe mark on it.
The roller must be adjusted so that the scribe mark on the cam is aligned dead center with the roller when they make contact. This is the point where the throttle butterflies should just start to open....... not before or after.
Thanks a lot Joe. I ran it yesterday and it seems to work pretty good, better than usual.
I had a couple of questions from your low speed needle valve adjustment method. Is the method for achieving idle with the motor in water and in forward gear, motor in water, or motor out of water. I ask only because I would like to get the carbs "worked out" and then not have to worry about them anymore.
The book says gently seat and then back out 5/8 turn and go from there as well. Not trying to split hairs...
Your information on the point gaps is particularly interesting, I need to go back and check each lobe entirely.
A couple more items I ran into during my last test on the water. The distributor points plate hangs up after the engine warms up. That is to say the plate the points are mounted to is made to rotate around the crank and attached to a linkage from the throttle arm. After my engine warms up that plate hangs up somewhere. The result is when I try to advance the throttle from idle the carbs start to open and the timing doesn't advance (obviously the motor doesn't run well). I am going to disassemble, clean, lubricate, and reassemble today. What advise would you give on lube type and location (planning to use triple guard).
Also, this motor has an auto half choke feature when cold starting. The problem is that after I run the motor and sit for a half hour and then try to start it again it auto chokes. The engine is still essentially warm so it won't start in this condition. This is something I combat by turning the choke off in this particular situation (on motor) but it also may be good for others to know.
P.S. I am starting to figure out the gremlins and it all makes a lot more sense now. Here is a bit more troubleshooting tidbits for your bag of tricks.
Q - why after running so well at full throttle and then stopping and trying to go again does the motor die?
A - Because when the engine warms up the distributor advance hangs up. The throttle mechanism forces the distributor plate back to idle when you slow down but relies on spring force to advance it when throttling up. this may answer a couple of the "it runs so well when it is cold but then mysteriously loads up when it's warm" type questions. With so many parts working in harmony it's necessary to make sure they continue to work warm or cold.
Q - Why after the engine warms up does it have such a hard time starting again?
A - Because the auto choke improperly engages in situations when the engine is still essentially warm but has had some time to cool. I'd prefer a choke that only engages when asked...
Various OMC engines that were manufactured in the later 1960s thru the early 1970s, for example the 1969 55hp Evinrude/Johnson incorporated a dual stage choke solenoid...... easy to identify as they have two wires leading to the solenoid, one purple/white, one purple/yellow.
The purple/yellow is attached at the engine wiring terminal strip to another purple/yellow wire that led to a heat sensor. The initial stage, with the key ON, (purple/yellow), when cold, would keep the choke pulled in half way until the engine warmed up, at which time it would release and open the choke butterfly.
The second stage (purple/white) is attached to another purple/white wire at the engine terminal strip which leads to the choke switch. When the switch was engaged, the choke closed etc.
The problem with this setup is that as the engine got older, the thermostat acted up, water pump became weak, whatever, the heat sensor failed to operate properly and the choke would not release from that half closed position. This would cause the engine to run in a rich fuel mixture condition (flooding, loading up).
The cure to this problem, via a service bulletin from OMC was to remove the solenoid purple/yellow wire from its original location and connect both of the solenoid wires (purple/yellow & purple/white) to the engine wiring harness purple/white wire at the engine terminal strip.
The above change would allow both solenoid wires to be energized when the choke switch is engaged, pulling the choke butterfly in firmly..... and only when the choke switch is engaged.
But have you checked the filter that is on the fuel pump? On my 1977 55hp Johnson there is a little wire mesh filter inside the fuel pump (very easy to get to, no tools needed!) that had a few small pieces of crud in it. I cleaned it and, not that I was having a problem before, but it seemed to run nicer.