73 Evinrude 115 ignition system

[AEROISTIC2]

Original problem--Engine would run fine for about 20 minutes then would lose about a third of its power then full power would return just to go away a few moments later. After inspecting the engine the yellow wire on the rectifier was found to be grounding out. I replaced the rectifier and tested the engine to find out I had no fire at the plugs. I tested for voltage at the stator leads where of course there was none. Upon inspection of the stator a number of burn spots were found and a beezwax like substance was leaking out of it. Obviously I replaced the stator. I then had voltage on the leads to the power pack but still no fire at the plugs. Just for a shot in the dark I replaced the power pack which left me with two plugs firing. The sensor coils where testing good but I said what the hell and replaced the timer base and two coils that had some hairline cracks in them. Now I have all four plugs firing. I got pretty excited until I installed the plugs and tried to start the motor and recieved the now all to familiar sound of an engine turning over and refusing to start. I removed one plug to check for fire and of course there was none so I removed a second and then a third then they all started firing. I understand that engine rpm is important when starting however the engine is turning over at the same rate it always has. So after all that here is my question. Did I get some bogus aftermarket parts that requires some unusual high rpm rate to run this engine or should I be looking for something else? I'm running out of places to look. Let me also add that I'm using a new 1000 cranking amp battery. The starter does get warm but nothing I think is unusual from the amount of cranking its been doing lately.

 

[WillyBWright]

Re: 73 Evinrude 115 ignition system

I'd probably start by replacing the other two coils. If two are cracked, the other two probably are too. They're probably cracked someplace you can't see. That won't kill the system, but those two could be misfiring intermittently.<br /><br />But before I spent any more money, I'd give the ignition switch consideration. It could well be corroded inside and causing these problems. Most of the time you can feel it when you turn the key. It would feel a bit sloppy and not lock into the off-on-start detents well. You might try spraying WD-40 into the keyslot profusely to maybe flush some crud out of there, work it with the key a few times (battery should probably be disconnected) flush it again, and blow it clear with compressed air. Keep a few clean rags around the switch as you do this and you'll see what comes out on them. You might have to do this 2 or 3 times. There's a good chance this will help the switch, or it might just be worn out. I'd also check all ground connections and look at the wires for wear against some sharp metal somewhere.<br /><br />I don't recall if that has a red main harness plug. I think that came a few years later. If it has, you could have a newer control with a lanyard kill switch. Those originally had rubber caps that stretched and rotted. Those are plastic forks now. Same switch, different tether.

 

[Joe Reeves]

Re: 73 Evinrude 115 ignition system

The spark must be tested with the spark plugs REMOVED. The spark must be able to jump a 7/16" gap with a strong blue lightning like flame.... a real SNAP! Anything less indictaes that a problem exists.<br /><br />The ignition system is self contained, meaning that it does not depend on a battery voltage supply for power to the powerpack etc.<br /><br />However, the engine must be turning at least 300 rpms in order for the flywheel magnets that are spinning past the black stator coils to develop and supply the approximate 300 AC volts to the powerpack.<br /><br />Loose or tight but dirty cable connections that exist anywhere in the electric starter circuit will result in a voltage drop that will in turn result in low cranking rpms, especially with the spark plugs installed. Check, remove, clean, and re-tighten all of those connections. Use a wrench or pliers, not your fingers.<br /><br />Of course, a low cranking rpm, even with all connections being clean and tight and assuming the battery is okay, can be due to a electric starter that is not up to factory specifications.<br /><br />If no spark, a check of the ignition switch can be done by removing the black/yellow lead from the powerpack, then (s/plugs removed) cranking the engine over. If you now have proper spark, replace the ignition switch.<br /><br />Let us know what you find.

 

[AEROISTIC2]

Re: 73 Evinrude 115 ignition system

The ignition, kill and neutral switch has been tested several times they check out ok. The black and yellow lead has been removed several times during trouble shooting and ohmed out for shorts to ground. It works fine in relation to the ignition switch position. Battery cables solenoid cables and starter cables have been removed cleaned and reinstalled. I'm getting a good 7\16 spark on all coils with my not so pretty gap tester. I will change the other two coils as soon as I get a running engine. I don't belive they are my current problem. I'm certain its an rpm problem but I dont think that even with a new starter I'll be able to get the rpms that I need to start the engine with all the plugs installed. I've orderd a rebuild kit for the starter and I'm looking for an rpm gun to determine flywheel rpm during cranking with all plugs installed. When testing rpm where do I put the sensor? On the center, middle or outer edge of the flywheel?

 

[AEROISTIC2]

Re: 73 Evinrude 115 ignition system

I just removed, dismantled and inspected the starter. Other than some carbon dust everything looks good. The brushes show very little wear and the springs seem to have plenty of tension. There was no evidence of arching at all. The armature and commutator are in execellent visual shape. I cleaned, reassembled and reinstalled the starter. The starter continues to turn at the same rate it alway has. I'm certain I'm getting at least 300 rpms out of it but I've yet to determine that for sure.

 

[R.Johnson]

Re: 73 Evinrude 115 ignition system

On this engine, you can adjust the air gap between the sensors' and the flywheel magnet in the hub of the wheel. Rapair sell's a guage to do just this. The part number is R553-9702. I would bet this will cure your no spark problem with the plugs' in. I have posted this answer before. If you can, test voltage output before, and after adjustment. Tell us what you find. The guage is about $10- $15.

 

[AEROISTIC2]

Re: 73 Evinrude 115 ignition system

My problems are solved went out late last night with the intentions of beating it up with hammer. Instead I began checking ground connections. I pulled the main ground and it was still clean and tight from the last cleaning. I pulled the ground stud out, which I didn't do last time, and cleaned the stud and the threads in the block then reinstalled the stud and ground connections. At this time I had three plugs installed and turned over the motor. The remaining dangling plug gave off a nice sharp blue spark! I then installed the plug, pumped up the fuel bulb and turned the motor over. With a little help from the choke it fired right up. Tomorrow I will put it in the water for a test run. I still have a few questions though. I bought four new plugs from the dealer, they have anodes on them and so did the ones I removed. The manual however shows a surface-fire plug being required. Are the new plugs an acceptable replacement or do I need to find another plug? I also changed the gear lube in the lower unit. When I drained it, it had 90 weight gear oil in it. The manual says to use Dexron II transmission fluid. I filled the unit with the transmission fluid but I'm wondering if I should expect a premature failure in the lower unit because of the gear oil. I ran the engine for a year and there is no telling how long the previous owner ran it. Now that the engine is running I'm going to go ahead and replace the two remaining old ignition coils and the ignition switch. Your help on this matter has been much appreciated and thanks for the emphasis on checking all ground connections in your other posts. When your sitting there looking at a wire with a snug bolt on it you tend to take it for granted that it is doing its job.

 

[Joe Reeves]

Re: 73 Evinrude 115 ignition system

A 1973 115hp Evinrude requires that the lower unit be filled with what is called HiVis gearlube which is available at Wal*Mart, K-Mart etc, and alos at your local dealership at a higher cost of course.<br /><br />If that Dexron II transmission (I'm not familiar with it) fluid is of the automatic transmission type fluid, that fluid is way too thin and would be inviting a disasterous lower unit failure.<br /><br />The spark plugs should have the electrodes and the desired plugs would be Champion QL77JC4 plugs gapped at .040 . The other non-electrode plugs last longer but they actually have no heat range to speak of and are therefore cold natured and prone to fouling.

 

[AEROISTIC2]

Re: 73 Evinrude 115 ignition system

^where can i find a rebuild kit for the rams on the power tilt and trim?

 

[ledgefinder]

Re: 73 Evinrude 115 ignition system

The Dextron is recommmended as an alternative LU fluid in the factory manual, so don't panic you won't ruin the LU. I'd put in the Premium Blend you can get from your OMC dealer (or 'Type C' aftermarket). <br /><br />The 1973-77 LU, though it's cable shift, does have a hydraulic assist and will shift a little more cleanly with Premium Blend than with the HiVis. It's more noticeable with a cold motor in cold water, so maybe not as important in Louisiana. Premium Blend is lighter, and required in electric shift.