Oily, black sparkplugs

[puddlesplasher]

Hi all,

A few weeks ago I had problems when the Johnson 30hp O/B refused to start on the 3rd outing following a service. Cylinder head gasket was replaced, new plugs etc....(under warranty)

Same thing then happened after a further 2 outings. last week I cleaned the plugs, tightened the Cyl.head gasket and everything worked again at the first turn of the key.

However today the problem returned and the O/B wouldn't start halfway throughthe day. Whilst at sea I replaced the old for new sparkplugs. This worked until my final drift when the O/B wouldn't start and I ended up using the auxilliary. (worst part was the shark that only 30 yards away. No I am not kidding. Basking I believe)

Upon inspection the new plugs had turned black and oily looking. There was a petrol/oil residue/fluid within the sparkplug where "gap" is.

My thoughts are:

1) Flooded engine hence the fuel in the sparkplug.
2) Incorrect gap but that shouldnt happen on all the plugs?
3) Incorrect mixture. I use a 50:1 as recommended. 20ml per litre and I use exact measurements of fuel per litre dispensed .

Perhaps it is an easy fix so guys, it is over to you.

Help!!!!

 

[wilde1j]

Re: Oily, black sparkplugs

Oily black plugs usually indicate running too rich. A number of potential causes such as choke engaged or not fully open, any carb inlet restriction, etc.

BTW, I assume you used a torque wrench when you "tightened the Cyl.head gasket" and tightened to the correct torque value.

If it's in warranty, take to a dealer and don't mess with it yourself, unless you want to compromise the warranty.

 

[F_R]

Re: Oily, black sparkplugs

Oily, black spark plugs are not unusual these days. But liquid fuel in them is. For some reason, that motor is severely flooding.

 

[puddlesplasher]

Re: Oily, black sparkplugs

Oily, black spark plugs are not unusual these days. But liquid fuel in them is. For some reason, that motor is severely flooding.

That explains the smell of fuel although I couldnt see the tell-tale slick on the water.

Where can the fuel be flooding from?

 

[F_R]

Re: Oily, black sparkplugs

Carburetor float valve??

Ruptured fuel pump diaphragm??

Primer??

 

[puddlesplasher]

Re: Oily, black sparkplugs

I have just visited the mechanic. He says I was starting the O/B in the wrong manner.

He asked the same questions as you guys have, oil type, gap.....

Under advisement I went home with the plugs, disconnected the deadmans cable, plugs already removed and then cranked the O/B.

Then I was to put the plugs, gapped at 0.67 metric back into the O/B. Lift the fast idle lever. Thereafter put key in ignition, turn clockwise to ON position, THEN, push in, hold and turn to start. (water and muffs on)

It appears that I didnt see him turning the key to the On position then pushing in the key and holding followed by turning.

I had been pushing in the key and holding in the OFF position then turning to ON so thats why there was no choke

Sometimes it the simple things that ***k us up but at least it started first time from cold

Thanks all for the effort and time taken to assist me