Cut out. now???

[2mate]

I was running my 1976 evinrude 40hp pull start in the bucket the other day and it just stopped which i immedietly though ignition. Fuel is good compression is good but i have no spark. Both coils are good, clean and gapped points and condensors are good. Maybe something to do with the weird stop button vacume thing?

 

[2mate]

Re: Cut out. now???

 

[F_R]

Re: Cut out. now???

Did you go into the ignition AFTER it quit? I suspect it sheared a flywheel key. It is NOT the vacuum cut-out switch, if that is what you are asking. But could be the kill button or wires leading to it.

 

[2mate]

Re: Cut out. now???

But if the key sheared it would still spark just out of time? How do you know its not the vaccume cut off?

 

[F_R]

Re: Cut out. now???

No, if the key is sheared, it will not have spark because the flywheel magnets won't be in sync with the breaker points.

I know it is not the vacuum cut-out switch because it just doesn't work that way. After 24 years experience as a full-time outboard mechanic, I pretty much know how those things work. In the first place, they only cut out one cylinder, not both. Besides that, they are extremely reliable, very rarely giving any trouble. But I suppose after 30-some years the diaphragm could be rock hard and not work at all. If it were rock-hard, it would be flexed in the "open" position, not the closed or cut-out position. Again, if that were the case, it would not affect the other cylinder.

 

[2mate]

Re: Cut out. now???

Okay thanks for getting back to me. Il check the flywheel key and let you know how it goes. Thanks for the advice

 

[2mate]

Re: Cut out. now???

The key is not sheared and the stop button is continuos when the button is pressed in. This indicates to me it is all okay? What next?

 

[2mate]

Re: Cut out. now???

Also i dont like the omc ht leads with the spring as i am never sure there is good contact. I was thinking of changing these to Screw in NGK ones. Is this a good idea?

 

[Tim Frank]

Re: Cut out. now???

I was running my 1976 evinrude 40hp pull start in the bucket the other day and it just stopped which i immedietly though ignition. Fuel is good compression is good but i have no spark. Both coils are good, clean and gapped points and condensors are good. Maybe something to do with the weird stop button vacume thing?

1) How did you test the coils?
2) My friend's '76 40 HP has three coils....one under the flywheel.

 

[F_R]

Re: Cut out. now???

Also i dont like the omc ht leads with the spring as i am never sure there is good contact. I was thinking of changing these to Screw in NGK ones. Is this a good idea?

OK, so my flywheel guess didn't pan out. Here are some more:

The OMC blug boots are just fine. They were successfully used on millions of motors. But you should strip about an eighth inch of the wire and fan out the wire strands so they contact the spring. And try your best to get the prong through the wire strands. But even if you miss it, the fanned stands will do the job.

Your 1976 has the OMC Low Tension Magneto with a driver coil under the flywheel and two external spark coils. There is an unlikely possibility that the driver coil is bad. A simple continuity check will tell.

Much more likely is BREAKER POINTS!! One set of points can kill both cylinders on that system. Recheck your work on the breaker points!!! I'm betting that is where the trouble lies.

One shorted condenser can kill both cylinders too, but that is fairly uncommon. But don't ignore the possibility.

EDIT: One more, then I'll shut up. How about the magneto plate ground wire? If it is loose, broken, or disconnected, it won't run.

 

[2mate]

Re: Cut out. now???

Okay cheers for the great advice! How should I check continuity of that coil? I think I might get a new set of points and condensors just to know that they are good. Il keep you guys updated! As for the wires which ones are these?Cheers

 

[F_R]

Re: Cut out. now???

Check the driver coil by disconnecting both leads from the points, then use an ohmmeter to check for continuity across the two wires. Should be 1.45 ohms (+/- .7 ohms). Also check either wire to ground, should be infinity.

Which wires?? You mean the ground wire? It is a short piece of wire connecting the mag plate to ground. Just one of them.

 

[2mate]

Re: Cut out. now???

I have just checked the continuity between both wires on the smaller coil under the flywheel and it is continuous between both wires. How should i check the larger coil?
cheeRS

 

[F_R]

Re: Cut out. now???

Similar test for the spark coils. Blue wire and ground, low resistance. Spark wire and ground, fairly high resistance (like several k-ohms). Sorry, I don't have the exact numbers.

But remember, it was running till it suddenly quit. Both coils aren't going to crap out and cause that at the same instant.

 

[Tim Frank]

Re: Cut out. now???

Is it too much like band-wagon jumping if I vote for the points, too?

By the way, what gap did you use for the points?

 

[2mate]

Re: Cut out. now???

I will be gapping them to 20 fowell.

 

[2mate]

Re: Cut out. now???

I now have spark on the top cylinder but not on the bottom cylinder :/

 

[2mate]

Re: Cut out. now???

Now sparking on both! Regapped the points and cleaned them now its running. Only issue is when it idles it splutters and coughs and dies as it does in the video. Then to start again you have to give it choke. It runs fine at high revs just wont idle. Any ideas?

 

[F_R]

Re: Cut out. now???

Coughing at idle is a sure sign of running too lean. Adjust the idle knob on the carb.

Other causes could be link & sync way out of whack, or induction leaks. But don't worry about stuff like that till you try the simple adjustment. Hey, the simple stuff fixed the ignition, didn't it?

 

[2mate]

Re: Cut out. now???

I guess so yeah! It has had new gaskets throughout including reed and carb gaskets. Do you know how many turns in the low speed screw needs from seat? That is the screw your talking about right? Cheers