1975 JOHNSON 85hp (85ESL75) lost spark on 1 & 3

[kesso]

Have intermittently lost spark to cylinders 1 & 3; the problem appears to be related to the wires running from the coil to the terminal board that sits at the rear of the motor. If i jiggle the wires the motor fires on 1 & 3 again. All connections are secure.<br /> 1. Does anyone know if the wires/insulation is prone to breaking down?<br /> 2. Is the voltage on the terminal board 12V?<br /> 3. Is it possible to re-wire and re-terminate the wire that runs from the coil to the terminal board or is it best to replace the coil/wire assembly?<br /><br />Regards,<br /><br />Kesso

 

[McGR]

Re: 1975 JOHNSON 85hp (85ESL75) lost spark on 1 & 3

In regards to your questions:<br /><br />1. I'm not sure if the wires are prone to intermittancy but I doubt it. OMC used good quality wire and terminations that would hold up well under harsh conditions. Howerver, if you can isolate a source of intermittancy by performing a jiggle test on the wiring, then that's the problem.<br /><br />2. The terminal board you refer to is actually the power pack or ignition module for your motor. As these systems are electronic magneto ignitions, they do not require a regulated voltage for operation. Internally they are basically a capacitor (CD ignition) that is discharged into the igntion coils through and array of SCRs. The capacitor is charged by the charge coil portion of the magneto and the SCRs are triggered by voltages induced into two sensor coils. In this system cylinders 1 & 3 share one sensor and cylinders 2 & 4 share the other one. Since you mention you are having cylinder 1/3 problems, I would suspect the 1/3 sensor or circuitry within the power pack, or possibly the interconnecting wires. The sensor can be checked with an Ohmeter. The nominal resistance of the sensor is 8.5 Ohms. The sensor inputs should also have infinate resistance to ground. Sometimes the sensors and powerpack can be checked by exchanging the sensor inputs and coil outputs from one bank (1/3) to the other bank (2/4).<br /><br />3. It's probably not recommended to re-wire and terminate the coils. However, I've done it successfully. When I did it I found the type of wire OMC used would not take solder well (even when extremely clean) so recommend using a butt splice and sealing it with RTV then adding shrink tubing over the splice. Make sure you use a good quality braided wire as a replacement for the original wire. Outboards are vibration machines and cheap wire won't last long.<br /><br />I hope this helps.

 

[kesso]

Re: 1975 JOHNSON 85hp (85ESL75) lost spark on 1 & 3

OK, that explains a lot.<br /><br /> I only had a set of Steinel Multi-checks on me the other day, so i could only check for continuity. All connectors on the power pack showed continuity between eachother and to ground...i was left scratching my head wondering what its purpose was; however, if the sensor resistance is only 8.5 Ohms, that would probably show up as continuity/short on the Multi-checks.<br /><br />1. On the 1/3 bank, besides the heavy-duty wires to the spark plugs, there is one normal gauge thin wire that seems to terminate in a little recessed hole on the lower cylinder head, it also goes back to the Power pack. What is it for? it looks like it is poorly terminated in this little recessed hole. There is not one, or a recessed hole on the other side on the 2/4 bank?

 

[McGR]

Re: 1975 JOHNSON 85hp (85ESL75) lost spark on 1 & 3

The small wire you are noticing sounds like the temperature sensor located on the starboard cylinder head. I don't believe this sensor interacts with the power pack/ignition system on this motor. Basically it is a bimetal switch that provides a path to ground when activated. This path to ground activates the over-temperature alarm.

 

[kesso]

Re: 1975 JOHNSON 85hp (85ESL75) lost spark on 1 & 3

I think i'll have to invest in a workshop manual for my motor, can you recommend any of the options as follows:<br /><br />1. Original OMC - Johnson Service Manual,<br /><br />2. Clymer - Evinrude/Johnson Outboard shop manual 48-235hp (1973-1990) ISBN: 0892875550 , or<br /><br />3. Seloc - Johnson/Evinrude outboards 3,4 & 6 cylinders (1973-1991) ISBN: 0893300101.<br /><br />Due to the cost of getting these manuals sent over, i want to make sure i get the right manual first time.

 

[McGR]

Re: 1975 JOHNSON 85hp (85ESL75) lost spark on 1 & 3

I've got both the original OMC and Seloc manuals for this motor (I basically have the same motor as you). Both manuals have their strengths and weaknesses. While either manual will do, I prefer the OEM manual for ignition problems. For other repairs (i.e. lower unit) I prefer the Seloc manual. One thing about the Seloc vs. OEM - the OEM seems to often expect you have some prior understanding of certain concepts in its repair and troubleshooting procedures. The Seloc manual approaches things more from a do it yourself perspective and assumes you have limited existing knowledge.<br /><br />I've never used a Clymer manual, so I can't comment on them. I hope this helps.

 

[dolluper]

Re: 1975 JOHNSON 85hp (85ESL75) lost spark on 1 & 3

Hum you jiddle the wires and it fires that should lead you to the problem bad wire or connections clean and tighten go from there

 

[Ross J]

Re: 1975 JOHNSON 85hp (85ESL75) lost spark on 1 & 3

kesso - this may sound peculiar but on my 85hp the power pack was replaced and I experienced a similar problem to yours. Eventually I simply got out the screwdriver and retightened all the connections on the powerpack, presto the problem went away - over a year now without a repeat. I reckon the powerpack connections "gave" a bit once tightened the first time, it was me who fitted it, when I checked I got a quarter turn on a lot of the screws. Worth a try mate!<br />Ross

 

[kesso]

Re: 1975 JOHNSON 85hp (85ESL75) lost spark on 1 & 3

OK, i have attempted a few repairs thinking the wires going to coils 1 and 3 were suspect, i replaced a re-terminated these wires....and no change to the original problem; hard to start and lose spark on 1/3; however still moving these wires allows the motor to start and gets 1/3 firing again.<br /> I did more investigation and this is how it stands:<br />1. Motor is hard to start at times and if it does start may not fire on 1/3, when i play with the wires to coils 1 and 3 and the sensor 3 wire, it will start and fire on 1/3...keep playing with the wires and the engine will stop firing/fires on 1/3.<br />2. If the motor is firing on 1/3 and i use a screwdriver to press on the terminal screws (they are tight) on the powerpack on either coil 1, coil 3 or sensor 3 wires...it stops firing on 1/3. It will do the same if i really tighten the screws super-hard also.<br />3. This powerpack appears to be white-mans magic and im thinking about buying another, im not sure it will fix the problem, i dont really understand how the item can be acting this way. Where is the best place to buy one of these items at a good price?

 

[McGR]

Re: 1975 JOHNSON 85hp (85ESL75) lost spark on 1 & 3

It sounds to me like you might have an intermittant connection within the powerpack. When I had a powerpack problem with my motor I bought a new powerpack. But I did disect the old pack just to see what was going on in there. Inside the pack there is a single PC board assembly that is interconnected to the terminal board with approximately 1/2" lengths of solid wire that looked to be about 20AWG (not sure if American Wire Gauge means anything down under). I think it is conceiveable that one of these interconnecting wires has become intermittant. In fact, the module I disected failed for this exact reason. The root cause of the intermittancy was actually corrosion that had formed under the terminal strip. This surprised me as I always assumed the potting would keep all moisture from damaging the internals of the module.<br /><br />I'm not sure of a good place to buy the modules in Australia. But over here, there are plenty of good deals to be had on-line. In fact, Iboats may even carry this part. You can also save a few dollars by using an aftermarket pack. I bought a Sierra pack for my motor and have been completely satisfied. Though, you may hear differing opinions on this topic. Some folks don't like aftermarket parts in general. I hope this helps...

 

[kesso]

Re: 1975 JOHNSON 85hp (85ESL75) lost spark on 1 & 3

Have ordered a new power pack, will let you know how it goes when i install it.

 

[ledgefinder]

Re: 1975 JOHNSON 85hp (85ESL75) lost spark on 1 & 3

Your motor (if it is a 1975) should have four ignition coils, one powerpack, and two sensor coils (on the timer base up under the flywheel). Your problem sounds like it might be the timer base, or at least it's worth checking out. One sensor coil triggers 1&3, the other triggers 2&4. Across sensor leads 1 &3 you should get 8.5 +/- 2.0 ohms; same across 2 &4.

 

[kesso]

Re: 1975 JOHNSON 85hp (85ESL75) lost spark on 1 & 3

I also have a manual on order for this motor, when it comes in ill dust off the multimeter checkout your suggestions.

 

[kesso]

Re: 1975 JOHNSON 85hp (85ESL75) lost spark on 1 & 3

Installed an aftermarket Sierra SIE185753 powerpack last night; the engine runs very nice now, seems to be a nice strong consistant spark on all cylinders.<br /><br />Did a compression check:<br />1-125psi 2-130psi<br />3-120psi 4-125psi<br /><br />In Australia, i was quoted $180 US dollars for this item; however i managed to purchase a powerpack from www.boatfix.com for $53 and have it flown to Australia for $13 for a total of $66 US dollars...bloody bargain! I thoroughly recommend these guys at boatfix.