1972 Evinrude 25HP weak spark

[Kenny1970]

Hello all I have a pull start Evinrude that has weak spark on the upper plug. The bottom will spark good and when I hold the plug and ground my self to the block I get shocked and the upper on will not shock me holding the plug.I swaped the plugs thanking they were bad but the same thing happens.If I put a screw driver in the uper plug wire I get shocked.
It just will not go through the plug. I pulled the fly wheel and cleaned the points and every thing looks good.
Before I replace every thing could some one that knows about these old outboards tell me if they ever had this problem before and what they did to fix it.
Also do they make a kit to do away with the points?
Thanks Kenny

 

[tashasdaddy]

Re: 1972 Ebinrude 25HP weak spark

Re: 1972 Ebinrude 25HP weak spark

if the coils and electronics under the flywheel have not been changed, they are long over due.

tune up kit includes points & condenser http://www.iboats.com/mall/partfind...gd_poid=111574&gd_row=18&**********=903306804


PULLING FLYWHEEL

you need a harmonic balancer puller, you need 3 - #8 harden bolts, that fit the 3 holes in your flywheel. standard hardware store bolts will strip out, causing more problems. loosen the flywheel nut, leaving it on so it protects the thread. thread the bolts in 7/16 of an inch. then tighten the puller, adjust so it has a straight pull. now tighten the puller, rap the center bolt with a hammer, then tighten some more. you may have to let it sit over nite, and repeat in the morning. this is a compression fitting, it will eventually POP!!. do not loose the woodruff key that goes in the groove of the flywheel and the crank shaft. then installing the flywheel, it has to be totally clean, no oil, woodruff key in place. then torque the nut to the specifications for your particular motor. if you do not do this, the woodruff key with shear, and you will be repeating these steps.


2 coils http://www.iboats.com/mall/partfind...1279&gd_partfinder=1&gd_poid=334777&gd_row=80

and spark plug wires http://www.iboats.com/Evinrude_Spar...9951643--**********.903306804--view_id.268739

 

[Kenny1970]

Re: 1972 Ebinrude 25HP weak spark

Re: 1972 Ebinrude 25HP weak spark

Thanks for the super fast reply.I dont know it the coils have been changed. The ones that are in it now are blue if that give you an idea. I dont know what the OEM color is.
I will start ordering parts now.I was kind of hoping there was a kit to do away with the points set up.
Thanks
Kenny

 

[Kenny1970]

Re: 1972 Ebinrude 25HP weak spark

Re: 1972 Ebinrude 25HP weak spark

hey Tashasdaddy I cant find that wire number when I click on the spark plug wire link you sent me. Do I go with the 25 foot kit?

 

[tashasdaddy]

Re: 1972 Ebinrude 25HP weak spark

Re: 1972 Ebinrude 25HP weak spark

points are more dependable, than the replacement system. i would pull the flywheel before ordering parts, if the coils are not cracked or discolored, 90% they are still ok.

 

[Kenny1970]

Re: 1972 Ebinrude 25HP weak spark

Re: 1972 Ebinrude 25HP weak spark

I will go out and look at them. I took the flywheel off last night.

 

[Kenny1970]

Re: 1972 Ebinrude 25HP weak spark

Re: 1972 Ebinrude 25HP weak spark

Any one need some plug wire I should have about 22 foot that I will never use.
Here is what I ordered.
I will let you know after the 29th how it worked.
1 Sierra Ignition Tune Up Kit
1 Sierra 18-5225 Spark Plug Wire Kit ""25 foot"" LOL!!
2 CDI 183-4477 Magneto Coil
2 Mallory Boot, Spark Plug (Spring Clip And Boot) 9-28124

 

[Mas]

Re: 1972 Evinrude 25HP weak spark

I had a weak spark on my 5 HP and couldn't flush out the problem. I checked and cleaned everything: points, condensers, wires, plugs, gaps etc!! The problem was that the points needed to be cleaned of everything...even slight oil residue. The answer was to use some "electrical parts cleaner" that does not leave any residue!

Problem solved! Maybe you have the same issue?

MAS

 

[samo_ott]

Re: 1972 Evinrude 25HP weak spark

I buy spark plug wire by the foot at my local OMC/BRP dealer. Unless the 25' are real cheap, I'd do it that way.

And if you post a photo of everything under the flywheel, it will help us.

Oh, and if you buy a cheap spark plug tester it will make it much easier for you to test. $5-$7 at Harbour Freight I believe I have heard.

And finally, did you change the plugs?

 

[Kenny1970]

Re: 1972 Evinrude 25HP weak spark

I had a weak spark on my 5 HP and couldn't flush out the problem. I checked and cleaned everything: points, condensers, wires, plugs, gaps etc!! The problem was that the points needed to be cleaned of everything...even slight oil residue. The answer was to use some "electrical parts cleaner" that does not leave any residue!

Problem solved! Maybe you have the same issue?

MAS

you know what every thing was kinda of oily under there.It looked like some one used half of a can of wd40 on it

 

[Kenny1970]

Re: 1972 Evinrude 25HP weak spark

I buy spark plug wire by the foot at my local OMC/BRP dealer. Unless the 25' are real cheap, I'd do it that way.

And if you post a photo of everything under the flywheel, it will help us.

Oh, and if you buy a cheap spark plug tester it will make it much easier for you to test. $5-$7 at Harbour Freight I believe I have heard.

And finally, did you change the plugs?

Here is your picture but I dont realy how it will help.
If you zoom in real close you will see the the brown wire on top of the coils have some kind of fuze still on them on them and when I ran my finger across the fuzzy wire,, it came off.Kinda like the stuff you seen on a car battery.
But there is no battery in this boat and it is a pull start only.
Thanks for the replys.
My parts are on order and should be here the 29th.
Kenny

 

[Kenny1970]

Re: 1972 Evinrude 25HP weak spark

Well I am in shock UPS just showed up with my stuff that was not sopost to be here untill the 29th.
IBoats shipping ROCKS!!!
Well I am headed out to play with it now the parts are here and see what happens.
Thanks every one.
Kenny

 

[Kenny1970]

Re: 1972 Evinrude 25HP weak spark

With the plugs out I put one plug in my hand conected to the plug wire.
With the other hand I turned the flywheel as fast as I could half of a turn and it knocked me on my butt.

It is fixed and I am still not sure what went out but I replaced every thing for just alittle over 100 dollars shipped to me and it took less than 30 minutes of work start to finish.

I am hopeing that this time it will last for another 36 years.

Thanks every one for the replys and I hope this helps the next person haveing the same problems searching the Threads.
Merry Christmas
Kenny

 

[tashasdaddy]

Re: 1972 Evinrude 25HP weak spark

change the impeller and tstat, and you will have a new motor. when i pull a flywheel i usually change it all. just makes sense to me, why go back.

 

[Kenny1970]

Re: 1972 Evinrude 25HP weak spark

change the impeller and tstat, and you will have a new motor. when i pull a flywheel i usually change it all. just makes sense to me, why go back.

Thanks for the advice. I changed the impeller a year ago and it still looks like it is pumping great, But I took the tstat out 4 years ago because some shop told me it does not get cold enough in texas to need one.

But I trust you much more than a repair shop that makes money on repairing screwed up engines.

Is there a standerd Tstat or what temp should I put back in it.
Thanks again.
Kenny

 

[HighTrim]

Re: 1972 Evinrude 25HP weak spark

Agree, put that stat back in. Could go into a detailed summary of why, but search the forum and you will finds loads of info. If the bean counters could of left it out, they would have! lol

part no 0378065

 

[tashasdaddy]

Re: 1972 Evinrude 25HP weak spark

for complete kit, including poppet valve you need sierra 18-3674
click evinrude parts at the top of the page. then cooling parts, tstat. yours is easy to do, since the stat is at the top of the head.

the motor needs the tstat to run at optimum temperature, which is 140-160 *. not using a tstat the water rushes thru the block, so fast it does not radiate the heat to the water, or cools too fast. thus it causes excess carbon build up. after you get it running well, it would do a decarb, (enema for the motor) to get the crud out.

Decarb, take a can of seafoam put 3/4 of it in the gas tank, with only 1 gallon of premixed gas. put the rest in a spray bottle. start the engine, and let it come up to temperature. then remove plugs, and them some real good shot of seafoam into the cylinders, replace plugs, let sit 15 minutes. restart, and spray the rest of the seafoam into the carbs, so the the motor almost stalls, wait and repeat until the seafoam is gone.then take for a wide open spin. then put in new plugs, ad premixed gas to the tank, and take it for a wide open throttle spin. it is going to smoke like a house on fire, during this process.

 

[Kenny1970]

Re: 1972 Evinrude 25HP weak spark

for complete kit, including poppet valve you need sierra 18-3674
click evinrude parts at the top of the page. then cooling parts, tstat. yours is easy to do, since the stat is at the top of the head.

the motor needs the tstat to run at optimum temperature, which is 140-160 *. not using a tstat the water rushes thru the block, so fast it does not radiate the heat to the water, or cools too fast. thus it causes excess carbon build up. after you get it running well, it would do a decarb, (enema for the motor) to get the crud out.

Decarb, take a can of seafoam put 3/4 of it in the gas tank, with only 1 gallon of premixed gas. put the rest in a spray bottle. start the engine, and let it come up to temperature. then remove plugs, and them some real good shot of seafoam into the cylinders, replace plugs, let sit 15 minutes. restart, and spray the rest of the seafoam into the carbs, so the the motor almost stalls, wait and repeat until the seafoam is gone.then take for a wide open spin. then put in new plugs, ad premixed gas to the tank, and take it for a wide open throttle spin. it is going to smoke like a house on fire, during this process.

Now this is some good info, But I have never heard of a poppet valve.
When it warms up I will do the sea foam treatment.

I also have some RING_FREE made by yamaha that I will run in the tank after the sea foam, Thanks Again.