1964 evinrude 28 - ran wrong (rich) mix, now no gas to one cylinder ????

[garboj]

1964 Evinrude 28hp speeditwin engine runs fine on Tueday, then Wednesday I mistakenly mix 32 to 1 instead of 50 to 1. Engine started, but only 1 (bottom) cylinder runs. Switched to gas tank with proper mix (50 to 1). Now Engine starts, but runs only on bottom plug. I definitely get good spark to both plugs during repeated visual test with plugs removed. Swiched to new plugs anyway to make sure. Recently checked and cleaned points following directions from manual. SPARK is not the issue! NOW, with engine running, when I remove top plug wire from plug, no difference. But, if I remove lower plug wire, engine dies. Compression is good: 112bottom/111top. Seems strange, but is it possible that rich mix fouled the card, allowing only bottom cylinder to get good mixture? There is only one carb on this engine, and it uses leaf valves. Could one be stuck "open"? I'm thinking gas is getting through, but not properly atomizing or somethihng?? Assuming the rich oil mix caused this, Is there a way to clear the offending oil from the carbs without removing the carb? OR, have I overlooked something else that could be causing this? THANKS.

 

[Paul Moir]

Re: 1964 evinrude 28 - ran wrong (rich) mix, now no gas to one cylinder ????

I don't think your rich mix had anything to do with it. '63 28hp engines, which are mechanically identical, used a 24:1 mix.

You can only rule out spark on these engines if you test with a wide gap, since that will show the most common way this ignition system fails (ignition coil cracks). You should be able to get both cylinders to jump a 1/4" or so gap. Jumping the .030" or so spark plug gap will not show ignition coil cracks. The wide gap simulates firing under load.

I doubt you've got a stuck leaf. Usually the symptoms of that are gas, sometimes flaming spitting out of the carb.

The fuel pump runs off the top cylinder on that engine. It's a long shot but it's possible that the pump started leaking gas into that cylinder. Easy to check - pop the fuel pump off (just the two screws, don't take it apart), pump up the primer bulb and see if gas comes out the small hole in the back of it.

Have you tried swapping/getting new spark plugs? Could be as simple as that.

 

[garboj]

Re: 1964 evinrude 28 - ran wrong (rich) mix, now no gas to one cylinder ????

thanks for the advice Paul.

okay, so i left both plugs in and started her up, but put the top plug wire on a third plug that was grounded against the engine. widened the gap quite a bit, and no spark while engine was running. on a regular plug, there is spark, but not so consistent - ind of jumps around a bit.

this makes sense, because if there was no gas to the top cylinder, I would have destroyed the top piston rings and there would be no compression, right? so, assuming it is a coil, is it common that they go one day without warning? can they be swapped to check to see if that's the problem? thanks!

 

[Paul Moir]

Re: 1964 evinrude 28 - ran wrong (rich) mix, now no gas to one cylinder ????

The original coils and replacements up through the 70s had a common defect where the coil's insulation would crack due to age. There's two things that are fortunate for you about this. First is that it's easy to spot a defective coil - the insulation is cracked. Second, since that coil was common to all their 2 cylinder engines produced from the early 50s to the late 70s, replacements are very cheap.
So pop the flywheel off and have a look. If it is the coils, the OEM # is 584477 and the aftermarket one is 18-5181. I actually like the aftermarket one better than the OEM one. If the spark plug wires are looking bad, now is the time to do them too. Use only metal core wire (not automotive "supressor" wire).

On a single carb engine, it's hard to kill one cylinder for lack of fuel. Even with bad leaks on the main crank seals it'll run ok. Broke reeds on old OMCs are very rare.

 

[garboj]

Re: 1964 evinrude 28 - ran wrong (rich) mix, now no gas to one cylinder ????

okay flywheel is off (again). no cracked insulation. I'm wondering if there is a ground taking place somewhere else? the previous owner was notorious for jimmy rigging stuff. the kill switch is a brown extention cord, with wires taped to the the brass pieces on the end of the cord ! (yeah, I'm getting around to it.) if the old wires is exposed, maybe that is killing the spark to the top plug. anyway, I will keep looking.... thanks for the tip on the plugs. i was obvioulsy getting a false impression of plug activity from a weak spark that failed under load. now to find the culprit... if it's the coil, you've saved me some head scratching.
thanks again Paul.
\john

 

[Paul Moir]

Re: 1964 evinrude 28 - ran wrong (rich) mix, now no gas to one cylinder ????

Sure could be. Set the flywheel back on (don't torque down the nut just yet) and disconnect & isolate the two black wires that come down from the armature plate. Check and see if spark returns. Obviously, don't run it like that.

My '62 28hp

 

[garboj]

Re: 1964 evinrude 28 - ran wrong (rich) mix, now no gas to one cylinder ????

i removed the kill switch wires just to be sure. then spun the flywheel by hand. i get spark, but it doesn't appear as consistant or strong on the upper plug. there definitly is spark on that plug, and that's what baffles me, but it's just weak I guess, and I assume under compression or what ever that it's not hot enough to ignite the gas mixture. I will replace the coil and let you know if that's the culprit...
yeah - nice '62 you've got there.
john

 

[Paul Moir]

Re: 1964 evinrude 28 - ran wrong (rich) mix, now no gas to one cylinder ????

Thanks. In the mean time, try cleaning the points and swapping the condensors (to rule them out). Also, if you've got a meter handy test for resistance between the spark plug boots and the engine block. You should get somewhere between about 3.7kohms and 7k. Just to rule out broken wires, etc.

Failing all that, swap the coils just to be sure. It sounds like you have more modern ones in there.

Under compression, the breakdown voltage of the fuel/air mix is much greater than at atmospheric pressure. When all is healthy that ignition system will produce arcs about 1/4"-3/8" long.

 

[garboj]

Re: 1964 evinrude 28 - ran wrong (rich) mix, now no gas to one cylinder ????

FIXED. I went ahead and replaced both coils, plug wires and caps, points, and caps. (I switched the condensors beofre the repairs with no change, so I assumed they were fine.) As long as I was in there, I decided to change everyting else to make sure it was fixed. Runs great at fast idle in the test tank (garbage can). I have no doubt that it is good to go. THANKS Paul for your assistance and encouragement !
John

 

[garboj]

Re: 1964 evinrude 28 - ran wrong (rich) mix, now no gas to one cylinder ????

NOT FIXED. Put boat in water, and lower plug wasn't getting spark. Before it was upper plug. New points are properly gapped at .020. new plug wires and caps were carefully installed. new coils were arefully installed. So, I bought one condensor (shop only had one) and replaced it, thinking this was the culprit since I had swapped them before, and maybe I confused the results. No help. Still no spark to lower plug. I obviously am doing something wrong. I bought a multi function electrical tester, and will try to figure out wher the problem is... but any suggestions would be greatly appreciated.

 

[i386]

Re: 1964 evinrude 28 - ran wrong (rich) mix, now no gas to one cylinder ????

Since your problem moved to a different cylinder, start troubleshooting from that point. Plug wires backward? That would put you back where you started I know but just thought I'd ask. Double check all your electrical connections in the magneto too. It's easy to leave something out.

 

[F_R]

Re: 1964 evinrude 28 - ran wrong (rich) mix, now no gas to one cylinder ????

So you have everything new in there except for one condenser? Hate to suggest it, but are you sure you replaced the right one? OK, OK. Otherwise, there are only a few suggestions that I can think of. One would be defective new parts. It happens. Or sometimes new points dont make good contact due to almost invisible corrosion to the metal contact surfaces which needs to be cleaned off. Check the resistance across them when closed. Should be zero and go to around an ohm if you open them with your finger. The ohm would be the resistance of the coil primary.

Speaking of the coil primary, make sure the wire isn't rubbing on something like the breaker cam. you wouldn't be the first one to make that mistake.

 

[garboj]

Re: 1964 evinrude 28 - ran wrong (rich) mix, now no gas to one cylinder ????

okay - thanks guys for the suggestions. if anyone has the electrical schematics for me to look at, i'd appreciate it - they aren't covered in the original manual....

 

[garboj]

Re: 1964 evinrude 28 - ran wrong (rich) mix, now no gas to one cylinder ????

Paul had said "test for resistance between the spark plug boots and the engine block. You should get somewhere between about 3.7kohms and 7k." - I get 11 ohms at both. is this an issue?

 

[mikesea]

Re: 1964 evinrude 28 - ran wrong (rich) mix, now no gas to one cylinder ????

are you positive the points are making good contact when closed,you can check with an ohms meter,did you swap the condenser again,is it possible that one of the points or condenser wires are grounding,do you have the kill switch disconnected again,is the kill switch wire grounding before the switch

 

[garboj]

Re: 1964 evinrude 28 - ran wrong (rich) mix, now no gas to one cylinder ????

Okay - I found this... kinda helpful...

 

[F_R]

Re: 1964 evinrude 28 - ran wrong (rich) mix, now no gas to one cylinder ????

Did you use "wire" wire when you replaced the plug wires? Automotive string core stuff is no good for outboards. That could account for high ohms at the wire boots.

The vacuum cut-out switch works on the lower cylinder to kill the lower cylinder if you rev it up too high in neutral. Might you be doing this? It should start firing again if you slow it down.

 

[garboj]

Re: 1964 evinrude 28 - ran wrong (rich) mix, now no gas to one cylinder ????

I bought the ignition wire from an outboard repair/parts guy. it is "hypalon ignition wire copper conductor". i am wondering if the wiring is correct. i found this Okay - I found this:
http://www.files.bz/files/3414/28schematic.PDF
seems to show the reverse of what i have coming out of the coils - i.e. green wires on top go to screw holding coil on, black wire from below goes to breaker scre. does this make a difference?

 

[garboj]

Re: 1964 evinrude 28 - ran wrong (rich) mix, now no gas to one cylinder ????

i am aware that the kill switch could be a problem. i disconnect it and get no change, but if the wire is grounding before the switch, that could cause this problem.. i'm not sure how to check for ground.. . ; ( electrical is my dark area.

 

[Xcusme]

Re: 1964 evinrude 28 - ran wrong (rich) mix, now no gas to one cylinder ????

I bought the ignition wire from an outboard repair/parts guy. it is "hypalon ignition wire copper conductor". i am wondering if the wiring is correct. i found this Okay - I found this:
http://www.files.bz/files/3414/28schematic.PDF
seems to show the reverse of what i have coming out of the coils - i.e. green wires on top go to screw holding coil on, black wire from below goes to breaker scre. does this make a difference?

Swap the 2 coil wires, black to screw holding down the coil, green to points screw. Route wires so as they don't hit crankshaft or flywheel.
Disconnect the 2 kill wires (one each at the points screw) as a test. Removing the kill wires means you'll have to choke the motor to kill it. Replace the 2 kill wires after testing.
Align with the crankshaft woodruff key with the points rub block and set to .020. Rotate crankshaft 180 degrees and adjust other set of points, again aligning points rub block with crankshaft woodruff key.