1971 Spark plugs

[jole]

Hello guys, I have a 1971 60Hp 3 Cylinders Johnson.
I have fixed almost every problem that it had. Now I have a spark plug problem.

In the last 14 days, 4 NEW spark plugs died on the 3rd cylinder. The first two plugs are greyish brown and dry, but the 3rd is black and a bit wet. Commpresion on the #1 and #2 is 150psi, on the #3 is around 143psi.

I think the problem isn`t electrical because i have only 1 coil for all 3 cylinders.
Some say that maybe there is water entering my 3rd cylinder.

The model is 60ESL71C, if it helps. And sorry for my bad english.

Thanks, Jole

 

[kenmyfam]

Re: 1971 Spark plugs

Black and wet should not be water entering the cylinder. More like not firing for whatever reason. I don't know your particular motor very well but someone will be along shortly that does.
Welcome to iboats.

 

[tashasdaddy]

Re: 1971 Spark plugs

if water intrusion, the plug would look steam cleaned. i would try running the motor at night, watch for any wild spark. the spark plug wire could be arcing to ground, instead of to the plug. those wire are expensive, NOTE: they SCREW into the distributor cap assembly. while running, pull each individual plug wire, you should here the motor drop rpms, replace wire rpms should pick back up. if no change that cylinder is not running, and you need to do more investigating.

i would also do a decarb, the bottom cylinder may be loaded with carbon.

directions in this >> http://forums.iboats.com/showthread.php?t=299680

 

[jole]

Re: 1971 Spark plugs

Thanks for a quick reply and welcoming me to the forum.

I tried pulling the wires down and it looks that all 3 are working. When the #3 plug dies there is a quite a diference to "normal" performanse.
It has a strange sound in low rev and it shakes like its working on only 2 cylinders, but when I increse the revs, sounds and feels like #3 has started working.
Like #3 isnt working on idle or really low revs. And still dont know why #3 spark plug would die repeadetly.
I`ll try to do a decarb and check the cables to the plugs.

Thanks, jole

 

[F_R]

Re: 1971 Spark plugs

Hello guys, I have a 1971 60Hp 3 Cylinders Johnson.
I have fixed almost every problem that it had. Now I have a spark plug problem.

In the last 14 days, 4 NEW spark plugs died on the 3rd cylinder. The first two plugs are greyish brown and dry, but the 3rd is black and a bit wet. Commpresion on the #1 and #2 is 150psi, on the #3 is around 143psi.

I think the problem isn`t electrical because i have only 1 coil for all 3 cylinders.
Some say that maybe there is water entering my 3rd cylinder.

The model is 60ESL71C, if it helps. And sorry for my bad english.

Thanks, Jole

What is wrong with your English?

I suspect two possibilities for your #3 problem:

1: The fuel pump is driven by #3, isn't it? A perforated pump diaphragm would dump extra fuel in the cylinder that drives it, causing a rich fuel/air mixture in that cylinder.

2: Have you adjusted the slow speed carburetor needles one at a time? Could be that #3 is just too rich. Or, along the same thinking, maybe #3 carburetor is flooding?

 

[jole]

Re: 1971 Spark plugs

1: The fuel pump is driven by #3, isn't it? A perforated pump diaphragm would dump extra fuel in the cylinder that drives it, causing a rich fuel/air mixture in that cylinder.

Thats right, I really didnt think of that. I dont know how the pump is build inside.
As a diaphragm, you mean the rubber gasket #2 on the picture?

So if i take down the vacum hose there shouldent be any gas, or?

I havent touched the carbs yet, I never get it back to the way it was before.

thanks,jole

 

[tashasdaddy]

Re: 1971 Spark plugs

No, F_R is talking about the diaphram inside the body of the fuel pump. there are a lot of small spring in there.

 

[jole]

Re: 1971 Spark plugs

Thanks guys, ill try things that you sead, im sure Ill be back soon.

thanks,jole