#1
IP: 68.188.145.18
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Oh no, another coil thread. More ohms???
Last summer I installed an electronic ignition. Immediately I started having trouble which turned out to be an overheating coil. I ordered a new coil from Moyer and the problem when away until today. The weather was getting rough so I was running the motor a lot longer and harder than normal and after about an hour it just died on me. I am almost positive it is the coil. It was hot to the touch. I did not have my multi-meter on me so I couldn't test it but based on my experiences last summer I am 95% sure that it. How many OHM is the Moyer coil? Is there any harm going up another .5 or 1.0 OHM? Part of the problem is that my coil is still mounted to the engine block near the exhaust so I will be relocating it at this time as well.
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1971 Ericson 32, Atomic 4 1976 Catalina 22 Ludington, MI - Lake Michigan |
#2
IP: 24.152.132.65
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The MMI coil should measure around 4.3Ω but if it has truly experienced an overheat all bets are off. Please measure the alternator output voltage and coil + terminal input with the engine running at 1500 RPM to see if there is excessive charging voltage (sounds like a possibility). Throwing resistors at it without taking these measurements is a work-around and does not help in analyzing the real problem.
The engine does not have to run at that RPM very long, just enough to make the measurements.
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Neil 1977 Catalina 30 San Pedro, California prior boats 1987 Westsail 32, 1970 Catalina 22 Had my hands in a few others |
#3
IP: 96.36.20.66
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Quote:
I did read somewhere (maybe here, but now I can't find it) that after changing the gap on their spark plugs the coil problem when away. What Gap are you guys using. Also what plugs? Thanks!
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1971 Ericson 32, Atomic 4 1976 Catalina 22 Ludington, MI - Lake Michigan Last edited by krazzz; 08-06-2015 at 11:58 AM. |
#4
IP: 107.0.6.242
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The Moyer coil is a little over 4 ohms and can take more of a (voltage) beating than the NAPA - but it is not invulnerable and with today's charging voltages ought to have a resistor in front of it, though it would require less of a resistor than the NAPA coil. If you do go with a NAPA coil make sure you have at least 1.5 ohms @ 50 watts in front of coil+. The boyz at the parts counter can look it up or I'll post a link if you like. Don't throw that Moyer coil away, however. It is very sound policy to get the coil off the block and mounted on a convenient bulkhead.
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#5
IP: 71.118.13.238
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krazz, the additional gap you can run with the EI helps the idle and performance over the long run. However that additional gap will do nothing to influence the heating of the coil. The heating is the additional "dwell" of the EI and this is magnified with our slow turning 4 bangers so good VOLTAGE control to the coil is a must. IE most any coil does not need the amount of dwell for proper saturation of the primary, thus the heating as voltages rise.
I run 10.5 Volts to my coil when the charging system reads 14 and have done so for many years. In the 45 years my engine has had 3 coils of which I tossed the stock one when I built my own EI back in 83. I started using a resistor about 5 years ago and replaced my functioning coil again when I did so. Never had one burn out with the stock alt. Dave Neptune |
#6
IP: 107.0.6.242
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How Low Can You Go?
Happy motoring!
Last edited by hanleyclifford; 07-13-2016 at 08:26 PM. |
#7
IP: 96.36.20.66
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Ok, so I just ran down to the boat at lunch. Started right up so the coil is the lead culprit. Checked the OHM of the coil and it was 4.0. With the key on, engine off the voltage at the coil was 12.5. With the engine idling I was unable to get a solid reading at the coil, the numbers were jumping all round (what does this mean?) I did get a reading at the alternator and that was 13.5. I ran it up to 1500 RPM and the reading was 13.67.
So... where do I go from here? I don't plan on running the engine this hard very often but it would be nice to know i could if I ever had to. I did notice the coil mount was a little loose and maybe caused it to vibrate too much???
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1971 Ericson 32, Atomic 4 1976 Catalina 22 Ludington, MI - Lake Michigan |
#8
IP: 107.0.6.242
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If I were in your position I would put a 1 ohm 50 watt resistor in front of that Moyer coil right now. It is possible, however that the coil has suffered irreversible damage and will fail anyway - but maybe not. Buy the new NAPA coil as a spare. Continue to monitor voltages especially at cruise rpms. BTW, at cruise, voltages less than 14 volts at alt+ are a bit low these days. Move the coil off the block when convenient. Cooler is better with coils - always.
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#9
IP: 159.53.46.143
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This is interesting - poor ground / loose connection maybe?
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#10
IP: 71.118.13.238
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krazz, RE the voltage jumping around~are you sure you were on the POSITIVE terminal? The voltage being supplied should be steady, it is the negative side that will bounce around.
Dave Neptune |
#11
IP: 96.36.20.66
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Yes, I'm sure. I measured from that post with the engine off and it read 12.5. If it was on the negative post it shouldn't get any significant voltage. I have not touched anything on this setup in about a year and this is the first trouble I have had in at least 50+ trips. The big difference yesterday is that I ran the motor much longer than normal ~ 1hour and was pushing it pretty hard at about 1800 - 1900 RPM into a strong head wind with 6-10ft waves (we were getting soaked!) I usually only run about 15-20 min at 1,200 RPM. I have to admit I am a fair weather sailor and typically only go out on beautiful sunny days I don't see a repeat of this trip any time soon.
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1971 Ericson 32, Atomic 4 1976 Catalina 22 Ludington, MI - Lake Michigan |
#12
IP: 71.118.13.238
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krazz, if you were indeed on the positive side the voltage should be steady engine running or not. If it was not steady running you have a weak connection somewhere, perhaps the key switch.
I run for 5~6 hours at 2200 regularly and have had no issues. Perhaps you should try "hot wiring" to check next time. Just have a wire ready to check if it dies or stumbles. Dave Neptune |
The Following User Says Thank You to Dave Neptune For This Useful Post: | ||
Vermonstah (08-07-2015) |
#13
IP: 96.36.20.66
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You might be on to something. I did upgrade my gauges a few months ago. I had to pull the panel to do it. It is possible one of the wires has come loose since then. Good place to start.
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1971 Ericson 32, Atomic 4 1976 Catalina 22 Ludington, MI - Lake Michigan |
#14
IP: 66.102.6.171
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What troubleshooting have we done to confirm that the coil is the problem and if it is, what caused it to be a problem?
Bill |
#15
IP: 96.36.20.66
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Still troubleshooting. Last summer I put a new electronic ignition on it and it had a 3.0 OHM coil. It would run for 30- 45 min and then cut out and not start for an hour or two. Then I realized it was the wrong coil. I got the MMI coil and everything was good for a bout a year. Yesterday I was running the motor for about an hour and it just cut out exactly like it had last summer. Sailed back to the dock and tried again but it still wouldn't start. Went there during my lunch and it fired right up without me touching a thing. It matches the symptoms I had last summer exactly however I have not been able to rule out other causes. I did rule out fuel as everything was good there. My control panel wiring is my next stop. Unfortunately I will be traveling for business for 3 weeks and I'm not sure I will be able to make it down to the boat before I leave.
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1971 Ericson 32, Atomic 4 1976 Catalina 22 Ludington, MI - Lake Michigan |
#16
IP: 96.36.20.66
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I realize the output isn't as high as people would like but it appears to be the original alternator and at 44 years old if it ain't broke don't fix it. I have shore power so my batteries are always topped off and most of my sailing is 3-5 hour day sails so I've never had to worry about charging fully depleted batteries. If I ever start doing longer trips a new alternator is on my list of upgrades.
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1971 Ericson 32, Atomic 4 1976 Catalina 22 Ludington, MI - Lake Michigan |
#17
IP: 205.178.100.207
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Because of the sudden shut down it is most likely electrical, but if the coil and grounds sort out ok. Bouncing around on Lake Michigan chop for a couple of hours could really get a lot of crud bouncing around the fuel system if your fuel system is original and you usually do fair weather sailing, could have been fuel related
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#18
IP: 184.0.17.64
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This from Don in a 2008 post regarding a similar shutdown situation...
"In your situation, if there is something else behaving like a failing coil, then changing coils isn't doing much more than snapping your fingers. In that case, there is a good possibility that the engine was going to start anyway when something else cooled down even if you didn't change coils. There is at least one other item that behaves in this manner (fails from heat and cures itself when it cools), which is a faulty connection in the primary ignition circuit (some electricians call these faulty connections cold joints, I suspect because they only work when they're cold). Please skip this paragraph if this is more than you wanted to know, but I am told by normally reliable experts that an electrical circuit sees a weak connection on the verge of failure as a localized zone of high resistance which translates into a small amount of heat build-up. As the heat builds up, the expansion created by the heat eventually causes the connection to open up (minuscule though this heat and expansion is, remember that a connection in this condition is on the virtual edge of failing anyway, even without the heat and expansion). To keep things simple, before chasing the entire primary circuit which runs from the large battery terminal on the starter solenoid, through the ignition switch and back to the positive terminal of the coil, you could simply connect a jumper wire from the large battery terminal on the starter solenoid to the positive terminal of the coil. If the engine never shuts down as long as that jumper wire is installed, you will have confirmed that the primary ignition circuit is a cold joint in it someplace. If the shutdowns continue with the jumper wire installed, you can check the remaining short section of the primary circuit which is between the negative terminal of the coil and the points. Sometimes the conductor in this short wire develops a cold joint where is passes under the distributor cap or at the terminal of the coil or at the points themselves. IMPORTANT NOTE: Installing the jumper wire between the starter solenoid and the coil is the very same thing as turning on the ignition switch, so you cannot leave that wire installed except when running the engine or you will burn out the coil or kill the batteries. " Hmmm...
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-Jerry 'Lone Ranger' 1978 RANGER 30 Last edited by roadnsky; 08-06-2015 at 08:05 PM. |
The Following 3 Users Say Thank You to roadnsky For This Useful Post: | ||
#19
IP: 107.0.6.242
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That information from Don is especially illuminating in light of the difficulty getting a solid voltage reading with engine running.
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#20
IP: 99.90.4.95
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krazzz,
where did you put the meter leads when you measured the coil volts? red on coil + and black where? |
#21
IP: 184.0.17.64
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Dave called it...
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-Jerry 'Lone Ranger' 1978 RANGER 30 |
#22
IP: 107.167.108.172
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Tonight I tested this. Red to the negative on the coil, black to a stud on the block. Voltage bounced around just as reported. Moved the red to the positive and it's rock solid. My coil is marked +/-, although faint. Can you confirm that you checked visually the coil to ensure it was on the +?
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#23
IP: 72.194.216.83
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Just to eliminate any ambiguity:
The small wire that runs to the distributor from the coil should be attached to coil -. The flow of electricity to ground will be interrupted by the points\EI when they open which will cause the voltage to "bounce around" at this terminal. TRUE GRIT |
#24
IP: 12.216.194.200
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The faulty reading could be the meter picking up the noise from the alternator.
Try this, twist the meter leads together and then try the measurement. The amount that the meter jumps around should go down. Put the meter on AC and this will show how much noise is in the circuit. With the batteries fully charged the VDC will be at MAX due to noload from the battery. I say its the coil, Steve Last edited by smosher; 08-07-2015 at 05:58 AM. |
#25
IP: 107.0.6.242
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Quote:
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