Plug quesion?

[dingbat]

Doing a little trouble shooting on a motor not that is running bad but but not running well either

Took it out and ran it about 25 miles at cruise (4000-4200 rpm), Camew back and hecked the plugs (77YJ4?) look nice and creamy on one side and brown/black on the other. Plugs generally looked good with the exception of this color difference.

Compression 100-105 all the way around and the carbs have just been rebulit.

 

[ezeke]

Re: Plug quesion?

The 1997 200HP Johnson line listed QL78YC, QL77JC4, and QL16V in their literature and parts manual. Boat setup now lists QL78YC. I am curious as to your choice of plugs. Did your dealer recommend them?

The color difference could be caused by temperature difference between the two banks.

 

[JB]

Re: Plug quesion?

How did you know what engine he has, ezeke?

 

[dingbat]

Re: Plug quesion?

My bad....the plugs are QL77JC4.

The color difference is from one side of the plug to the other. Split right down the middle of the electrode.

Checked to see if they where all "indexed" the same in relation to the brown side but found no clear cut pattern.

 

[Theoutdoorsman]

Re: Plug quesion?

My bad....the plugs are QL77JC4.

The color difference is from one side of the plug to the other. Split right down the middle of the electrode.

Checked to see if they where all "indexed" the same in relation to the brown side but found no clear cut pattern.

Can you explain what you mean by "indexed"? Just curious, I've seen this mentioned several times on the board. Thanks................ALAN

 

[ob]

Re: Plug quesion?

Indexed refers to the position of the plug electrode when installed.Some engines require a specific electrode placement for proper combustion.Carbed two strokes do not.

 

[Theoutdoorsman]

Re: Plug quesion?

Thanks OB.

 

[JB]

Re: Plug quesion?

Have you some objection to telling us just what the ROWRBAZZLE engine you are talking about, Seahunter??

 

[ob]

Re: Plug quesion?

He's got a thread further down the page titled 97' 200 Ocean Prf course since many members have more than one outboard,it would be difficult to advise unless we could be assured that it is the same engine in question here.It wouldn't be the first.

 

[dingbat]

Re: Plug quesion?

1997 200HP Evinrude Ocean Pro

And to clearfiy what I meant by "indexed" ,how does the brown side relate to the postioning of the plugs in the cylinder (.ie. brown side down, brown side up, left or right)