Spark Plug Appearance

rjbathgate · 02 October 2009, 06:06

Hey,

Pulled out and checked the spark plugs today...

I'm not sure if they are 'too dirty'...

See attached pics - I have gently rubbed with a brush, but could possible clean up a little bit more with a bit of elbow grease...

The plugs are only 60 hours old, and are very expensive, so I would prefer to clean and put back in --- but just wanted your thoughts before hand....

What would you do?

It's a 60Hp 2 Stroke by the way...

Cheers

matt h · 02 October 2009, 07:21

plugs look wet to me, have you been trolling on tick over to long?? if not then mixture slightly to rich? too much oil in pre mix? get the mixture right first, then give it a good run, i mean 2/3 throttle to full, take out plugs whilst on the jetty,.if still to rich, screw in the mixture screw 1/6 of a turn on the offending throttle and try it again!

aim for the first picture good luck

p/s i wouldnt change them, they look ok

Steve_B · 02 October 2009, 07:22

After those hours, I would say they are alittle too oiled up, but that really depaends on how the engine has been used. If you do a fair bit of low rpm stuff, then you might expect this.

It appears that there is no real wear on them, so I would clean them up and use again. Elbow grease is cheaper than plugs.

spartacus · 02 October 2009, 08:17

Some people don't recommend cleaning spark plugs in case you damage the electrode, however as you've mentioned, they're not cheap to replace. To clean, use a little brake cleaner and a copper wire brush (the same brushes you use to clean suede shoes). It's not as abrasive as a steel wire brush. Once cleaned, completely dry the plug. If you have access to compressed air - even better. Worth checking the plug electrode gap. Can be reset with feeler gauge (check the specified gap - refer to workshop manual for your particular engine) and tap gentle to desired height. Use a little copper ease on the thread and tighten.

jyasaki · 02 October 2009, 15:47

Are those pics before, or after you cleaned them?

If after, well, they're kind of worthless as a guage for how the engine's running.

If before, I'd say the left one looks fine, the other two a bit on the wet and carbonny side.

Then again, I don't run 2-strokes (except for a chainsaw.)

jky

m chappelow · 02 October 2009, 16:17

you could get that if a plugs not sparking proper too, eg, bad lead or faulty coil giving a poor or intermitant spark at certain revs,,,,some lower cylinders can run a bit cooler than the upper ones ,they should clean up if your carefull as said by sparticus using a brass/copper seude brush ,its not a bad idea to wipe/scrape inside the electrode rim where a lot of the grunge will be with a wood/plastic cotton wool bud stick or some thing,,,. i am not too sure about putting copperease/ grease on theads though especially an outboard ,though suppose you will only get galvanic corrosion if its below water level .

rjbathgate · 02 October 2009, 20:08

Quote:

Originally Posted by matt h

plugs look wet to me, have you been trolling on tick over to long?? if not then mixture slightly to rich? too much oil in pre mix? get the mixture right first, then give it a good run, i mean 2/3 throttle to full, take out plugs whilst on the jetty,.if still to rich, screw in the mixture screw 1/6 of a turn on the offending throttle and try it again!

Recently I have done a bit of low throttle stuff - in fact our harbour is pretty big and you're at 10 knots for about 15 minutes before you are allowed to rag it.... so if I was go give it a good run, and then come back to Jetty to check plugs, I'd've done another 10/15 mins at low throttle! Maybe I need to find a nice big lake....

And it's relatively new to me so I've not been flooring it as much as I could've been!

I'll give them some gentle cleaning, size up the gap and pop them back in for the season... maybe look at replacing at the end of this season... (it's summer over here!)

Cheers for all your advice

spartacus · 02 October 2009, 20:55

Quote:

(it's summer over here!)

We're getting ready to batten down the hatches. Only 5 degrees yesterday morning - definately a chill in the air. Enjoy those lazy summer days!

rjbathgate · 02 October 2009, 21:02

Quote:

Originally Posted by spartacus

We're getting ready to batten down the hatches. Only 5 degrees yesterday morning - definately a chill in the air. Enjoy those lazy summer days!

I knew there was a reason I emmigrated to New Zealand!

chewy · 03 October 2009, 18:26

Quote:

Originally Posted by rjbathgate

I knew there was a reason I emmigrated to New Zealand!

More sheep?

rjbathgate · 03 October 2009, 18:55

Quote:

Originally Posted by chewy

More sheep?

actaully, it's Possums we have lots off - something like 4 million people, and 90 million possums. It's almost like they're trying to take over.......

Locozodiac · 03 October 2009, 19:17

Cleam them dipping the whole plug tread in acrylic thinner for 5 minutes, scrape the dirt/sticking oil with a tooth brush, regap, clean cylinder inside threads in circular motion using a sushi stick, (like a big cotton swab) dampened in thinner, place lower cylinder plug in upper cylinder, and viceverse, rotate them in every maintenance service.

If you boat constantly, clean plugs every 50 working hours, if using a hour meter, the best. In 10 more hours my original plugs will have 250 metered worked hours, electrode looks surprisingly well as overall plugs. Like to cruise at 3/4 to wot throttle most of the time, correct gas/oil ratio is a must perform, these 3 issues are part of the package for their long longevity. But nothing is eternal, have a pair of new ones ready.

Happy Sibbing

Jizm · 03 October 2009, 20:15

Quote:

Originally Posted by rjbathgate

The plugs are only 60 hours old, and are very expensive,
Cheers

What plugs are they?

rjbathgate · 03 October 2009, 23:37

Quote:

Originally Posted by Jizm

What plugs are they?

NGK BPZ8H‑N‑10

Normal off the shelf plugs are about $8 here in NZ - these are $21 each.

Locozodiac · 04 October 2009, 01:29

Quote:

Originally Posted by rjbathgate

NGK BPZ8H‑N‑10

Normal off the shelf plugs are about $8 here in NZ - these are $21 each.

BPZ8H-N-10 will be :

B-14 mm thread
P-Proyected Insulator Type
Z-21 mm thread reach
8-Cold term
H-12.7 mm (1/2") socket
N-Special side electrode
10-1 mm gap (.040")

What would normal off the shelf plugs be : BR-7HS-10, BP6HS-10 ?

Happy Sibbing

rjbathgate · 04 October 2009, 03:27

Quote:

Originally Posted by Locozodiac

BPZ8H-N-10 will be :

B-14 mm thread
P-Proyected Insulator Type
Z-21 mm thread reach
8-Cold term
H-12.7 mm (1/2") socket
N-Special side electrode
10-1 mm gap (.040")

What would normal off the shelf plugs be : BR-7HS-10, BP6HS-10 ?

Happy Sibbing

I mean by off the shelf, I had to order my plugs in specially as they are not common, and not standard stock items I can pick off shelf... hence the price...

Locozodiac · 04 October 2009, 18:35

So that's the factory recommended plugs, a pity that BR-7HS-10 can't be used, other Yamaha models use this one. What about Champion brand compatibility ?

Happy Sibbing

Jizm · 10 October 2009, 08:40

Quote:

Originally Posted by rjbathgate

I mean by off the shelf, I had to order my plugs in specially as they are not common, and not standard stock items I can pick off shelf... hence the price...

You're not wrong, special order from my NGK supplier...

Cookee · 12 October 2009, 14:03

Quote:

Originally Posted by rjbathgate

I knew there was a reason I emmigrated to New Zealand!

My brother in law lives there - on the West coast opposite Auckland, havn't been to Tauranga but it looks like a great boating spot - any photos?

Will be over again next November ish I think!

rjbathgate · 13 October 2009, 01:21

Quote:

Originally Posted by Cookee

My brother in law lives there - on the West coast opposite Auckland, havn't been to Tauranga but it looks like a great boating spot - any photos?

Will be over again next November ish I think!

Yup, it's pretty nice here -- pretty much eveyrone and their dog has a boat over here... although not many ribs - most are into their fishing so have themselves big tinnies etc...

few pics of the area attached...