'69 Evinrude 33HP Ski Twin Wiring Question

[i386]

I've recently acquired a '69 Evinrude 33HP. I have very little history on it and trying to get myself acquainted with all the parts.

I'm trying to troubleshoot a no spark condition and I need to know a little about the wiring because it appears to have been modified somewhat.


Looking at the starboard side of the motor I have found what I believe to be the cutout switch. There's a pair of black wires that appear to go to the magneto area of the ignition system. One wire has a connector so it can be disconnected. The other black wire isn't connected to anything. In fact, it doesn't even have a terminal on the end. It looks like it was cut a long time ago.

As best I can tell from the diagrams available on this forum, it looks like it should be connected to post on the center of the cutout switch. The diagrams show 2 black wires connected to that center post. My motor has only one wire connected.

Should the black wire be connected to the center post? What happens if it's not connected?

Here's a few pictures. Sorry they're not very well focused. I should have used the macro setting.

Here's a view of the cutout switch. Notice only one wire is connected to the post in the center.

This image shows the pair of black wires coming from the upper left corner of the picture. As you can see, one has the connector on it. The other has a bare end.

 

[Paul Moir]

Re: '69 Evinrude 33HP Ski Twin Wiring Question

Only one black wire from the magneto should connect to the cutout switch. The other black wire you see coming off of it in diagrams runs to the keyswitch so it can be used to stop the outboard. When the keyswitch is turned to "stop", the black wire from the cutout is shorted to the other black wire that comes down from up under the flywheel.

It sounds like someone a long time ago disconnected the stop switch on your outboard. To determine if your no-spark condition is caused by something in the magneto or something outside it, disconnect and isolate the two black wires that come from up underneath the flywheel. If you still don't get spark, the problem has to be underneath the flywheel and it will need to be pulled for inspection.

 

[i386]

Re: '69 Evinrude 33HP Ski Twin Wiring Question

Only one black wire from the magneto should connect to the cutout switch. The other black wire you see coming off of it in diagrams runs to the keyswitch so it can be used to stop the outboard. When the keyswitch is turned to "stop", the black wire from the cutout is shorted to the other black wire that comes down from up under the flywheel.

It sounds like someone a long time ago disconnected the stop switch on your outboard. To determine if your no-spark condition is caused by something in the magneto or something outside it, disconnect and isolate the two black wires that come from up underneath the flywheel. If you still don't get spark, the problem has to be underneath the flywheel and it will need to be pulled for inspection.

Thanks. I believe the black wire that you see connected to the center terminal on the cutoff switch does go to one of the M terminals on the starter switch. But there's nothing from the magneto connected to the cutoff switch. I believe the bare wire I have hanging there goes to the cutout switch.

So basically if I understand his right one black wire goes from the underside of the magneto straight to one of the M terminals on the starter switch and the other black wire from the underside of the magneto goes to the center of the cutout switch and then on to the other M connector on the starter switch.

Is this correct?

I'm going by this diagram...
http://www.recaffeinated.net/evinrude/engineharness.jpg

 

[Paul Moir]

Re: '69 Evinrude 33HP Ski Twin Wiring Question

Yeah you've got it right.

To explain the function a little bit, when you suddenly snap the throttle closed on a 33hp in neutral, the carburetor can screw up the A/F ratio a bit. Which can send the engine into run-away where it turns up to incredible RPMS all by itself.

To prevent that from happening, when the vacuum switch detects a strong vacuum in the intake manifold, it'll cut the ignition to one cylinder and stumble the engine until the unusually high vacuum lets up.. It's normally the bottom one but I don't think it makes much difference. It does this by grounding out the bottom cylinder's point through the cranking safety switch. Normally the safety switch prevents the engine from being cranked over with the throttle set too far forward, but in this case it only allows the vacuum switch to function at all if the throttle is in the lower 1/3rd of it's range. Which prevents the vacuum switch from cutting out the engine at higher speeds.

To contrast that diagram, have a look at the one I drew for my 28hp:
http://www.files.bz/files/3414/28schematic.PDF
It's pretty much the same as the 33hp, except the position of the components (like the solenoid) is a little different. Yours is under the hood right?

 

[i386]

Re: '69 Evinrude 33HP Ski Twin Wiring Question

Thanks for the extra information. You drawing is a lot easier to read. Though it may be a little different than mine, the components we're discussing appear to be the same.

And yes my solenoid is under the cowl cover.

So I think that pretty much answers my question about that. I will go ahead and terminate my loose wire to the post. I'm not sure why it was off. One might expect to find a crimp terminal on the post with the wire missing, but that wasn't the case.

I will continue to troubleshoot my no spark condition. I found a good article on how to use my meter to check that out. I feel like I have enough information to eliminate the cutout switch as cause.

Thanks for all the help on this one. I'll be back i'm sure.

 

[Paul Moir]

Re: '69 Evinrude 33HP Ski Twin Wiring Question

No trouble. But do that test I told you about - disconnect the two black wires that come from up under the flywheel and tape them off (not together!)

If you don't have spark after that, the problem must be under the flywheel. Although I have a strong background in electronics, I never use my multimeter after that point. The problem can be found by just looking. Usually a broken flywheel key, dirty points, or cracked ignition coils. Just be sure to use a proper puller to get the flywheel off - one that uses the three ratchet bolts near the centre of the flywheel.

I forgot, I have an even simpler diagram without all the stuff for the generator on it:
http://www.files.bz/files/3414/28sch_NG.cdr-CorelDRAW.pdf

 

[i386]

Re: '69 Evinrude 33HP Ski Twin Wiring Question

No trouble. But do that test I told you about - disconnect the two black wires that come from up under the flywheel and tape them off (not together!)

If you don't have spark after that, the problem must be under the flywheel. Although I have a strong background in electronics, I never use my multimeter after that point. The problem can be found by just looking. Usually a broken flywheel key, dirty points, or cracked ignition coils. Just be sure to use a proper puller to get the flywheel off - one that uses the three ratchet bolts near the centre of the flywheel.

I forgot, I have an even simpler diagram without all the stuff for the generator on it:
http://www.files.bz/files/3414/28sch_NG.cdr-CorelDRAW.pdf

Hehe yea... That simplifies things A LOT. Knowing that I can isolate the magento components for testing will be a huge help. It makes a lot of sense too. Too bad I didn't think of that.

I've already had the flywheel off. It was easy too. The key is fine and there's no cracks in the coil. Everything looks surprisingly clean and new looking.

Tonight I will test my coils with my meter. I have been hesitant at this point to remove the points for cleaning because I don't see any marks on the cam for TDC. I need to make sure I can gap them properly before I start taking stuff out of there. Comparing an ohm reading with the points closed and open should give me an idea if they need cleaning without taking them out. As long as she's been sitting though im sure they need cleaning.

Nice diagram btw, definately a keeper in my Evinrude 33 folder.

I'm enjoying figuring this thing out. I expect to either have spark tonight or the reason why not.

Stayt tuned.

 

[Texasmark]

Re: '69 Evinrude 33HP Ski Twin Wiring Question

Not related, but it is. Having to have learned to ski behind an Evinrude 18 hp as an adolescent, I have to laugh my arse off at the ads that Dr. Evinrude placed where he labeled his 33 hp as a "Ski Twin". Yes, back in those days, a 33 hp was a big dude.......but what didn't we know then?

Today I'm buying a 2 litre 150 hp Merc on an 18' ProCraft for my son for his birthday.....and it has a ski post. 8)

Times have changed.

Mark

 

[i386]

Re: '69 Evinrude 33HP Ski Twin Wiring Question

Well, still no spark but I do have some more information.

Taking and ohms reading across the points with them closed I got about 1Ω. Not good.

I took them out and cleaned them. They looked pretty bad and should still probably be replaced, but looked much better after I cleaned tthem.

Taking an ohms reading again across the points with them closed they're at about .4Ω.


I don't think it was even in the realm of possiblilty to get a spark before cleaning, but afterwards I'd hoped for at least a weak spark.

I ran out of daylight before I could test any further. Tomorrow, I will test the coil and re-check the point gap. My meter doesn't have a capacitor setting on it so I'm not sure how to test the condensers.

I'll post what I find out tomorrow.

BTW, I did test with the two black wires that go to the M terminal and the cutout switch disconnected to eliminate the cutout switch as recommended by Paul Moir. I also unplugged the wiring harness to rule that out as well.

 

[Paul Moir]

Re: '69 Evinrude 33HP Ski Twin Wiring Question

It doesn't take much resistance in the points to defeat this magneto.

A long time ago, I tried to make an electronic point replacement for one of these. I initially used bipolar transistors as the switch, but the .7v drop between C and E made the spark very weak. In the end I ended up having to use MOSFETS with a RdsON of under .1 ohm!

(Since RdsON is directly related to maximum voltage, it turned out to be nearly impossible to make a reliable point replacement. I gave up on the idea. )

I've yet to see a bad condensor, but I have heard of them. Just assume they're fine for now.

 

[i386]

Re: '69 Evinrude 33HP Ski Twin Wiring Question

I'm not sure what happened. I posted eariler today and now it's gone along with the last post in this thread that was here this morning.

Here goes again...

Some dissapointment:

I removed the points again and cleaned the contacts with a needle file. They were nice and shiny this time. I reinstalled them and gapped them to .020". With the points closed, I checked them again with my ohm meter. They read fine but still no spark.

I also noticed the bracket the safety switch is mounted on was rusty. I removed that and sanded the rust off down to bare metal with my dremel too. I reinstalled the switch and checked it with my meter. That looked good. No spark though.

Next I connected one lead of my meter to the connector inside the spark plug boot and the other to ground. This test looked good on both plug wires.

Next I removed each coil for inspection. There were no cracks in either coil. The lead (needle looking thing) for the plug wired looked corroded though. I packed some steel wool down into the hole on the coil and worked it round with some fine needle nose pliers. The "needle" was clean. Not shiny, but the corrosion was gone. The center conductor on the plug wires where they connect to the coil had a powdery substance on them. I had no way to remedy that though. I tested again after reinstalling the coils. I get nothing on my meter. In other words it apears to be an open circuit on both coils from the connector in the boot to ground. I took the coils out again. The "needle" isn't bent on either coil and I didn't poke any new "holes" in the end of the plug wires when reinstalling the coils. The only thing I can figure is corrosion on the end of the plug wire where it meets the "needle" on the coil.

 

[i386]

Re: '69 Evinrude 33HP Ski Twin Wiring Question

I'll leave the above post here for comic relief (at my expense). My readings were wrong because I had the range set incorrectly on my meter! Duh!

The good news, sorta..

I got a good charge on one of the batteries that came with the boat finally. With a good battery, the starter works like a champ.
I still cannot get a spark to jump from inside the plug wire boot to the plug. I CAN gound the plug to the engine and turn the starter and see a spark though. So what we might have is a weak spark now instead of no spark. I can live with that for now!

The flywheel is back on tight and I'm moving on to the fuel system now! woohoo

 

[i386]

Re: '69 Evinrude 33HP Ski Twin Wiring Question

I never expected to report this today but IT RUNS!!!


So after finally getting some spark albeit a weak one I decided to move forward.

When I got the boat it had been sitting for about 3 years with a full tank of gas connected to it. Yikes. No way I was going to use that old gas can so I made my own out of a coffee can for testing. I spihoned some good gas out of my working boat's ('72 Chrysler 20HP) gas can into my homeade "gas tank".

After a few tries it would run for a few seconds with the choke on. After a few more it idled with no choke. There was only a weak sputtering of water coming from the tell tale so I went ahead and cut it off.

I was extremely happy that it ran. When I got my old Chrysler it ran but didn't run well. With the help of the manual I ordred and people from this forum, I got it running well. This old Evinrude was the first engine I've ever resurrected from the dead. Thanks again for all the help.

As soon as I can borrow a compression tester from my neighbor and verify that there's not too much variance between cylinders I'll try to get her running right.

If that checks out, a new impeller, points, plugs and some seafoam might be all I need.

 

[Paul Moir]

Re: '69 Evinrude 33HP Ski Twin Wiring Question

Good news! The Big Twins don't throw a big fat hot spark like you would see from a modern magneto with electronic ignition, such as a lawn mower. In fact, it can be trying to coax much more than a 1/4" long spark out of them. But that's how they normally run.

Go ahead and replace the impeller so you don't have to worry about it. But at idle you'll normally see a spurting/from the idle exhaust relief. In fact that is all the cooling water coming from there, except a minor amount that cools the midsection.