Saving Old Seagulls

Greetings and happy new year. I'm new to the forum and this is my first post. I know that spark plugs are generaly covered in the FAQs section, but I would appreciate some specfic advice. In the last year, I have acquired three Century models each with a different spark plug - Century short shaft with Champion D-21, Silver Century long shaft with Champion K-15J, and Silver Century Plus long shaft with Champion D-9J. I realize that the Champion D16 and D21 are generally recommended and thus want to be certain it's OK to run my seagulls with the other two plugs indicated. I use the longshaft seagulls as auxillary power for my 18ft welded aluminum lobster skiff and they will be required to run at full throttle for 2-4hrs if needed as backup. It is my understanding that some plugs are best for light regular use and others for prolonged running, which will be my case. I would appreciate recommendations on which spark plug I should use in my particular circumstnces, but I am also curious to know more about the specific characteristics of each of the Champion plugs I mention. Thanks very much. I think this forum is great and I look forward to a reply.

Does not answer your question, or does it. the NGK equivalent of all the plugs you mention is A-6.

This site may be of interest http://www.spark-plugs.co.uk/pages/tech ... hnical.htm

It explains the code for Champion plugs

Vic -I've gone to the website you indicate and am poring over the Champion technical information. This is a good start. Thanks for your reply.

champion D9 is best for hard running, I have done over 10 hours with my silver century in very rough conditions pushing a 14' heavy catboat, also I use a D9 in my 102 when on a long run, the D16 works well for long trips, I always carry a couple of spares. I use to oil up a lot of plugs because I used 30wght engine oil for the mix, changed over to modern 2 stroke outboard oil a few years ago and they run cleaner with fewer dirty plugs. have had the same D9 in my 102 for the last year

chris - Thanks for the feedback on the D9 - seems like that is the plug I should use. Would you happen to know what characteristics make the D9 best for hard running? Is it a cooler running plug for example? In relating your experience, you've also boosted my confidence in the silver century.

On a related note, can anyone shed light on why my silver century came equipped with a Champion K-15J, other than that it might have been the only plug the previous owner found that would fit?

i have found out through hands on experience. I don't know much about the technical side of seagulls, only what makes them very reliable. the D9 was recommended through an early seagull site for hard running. they are easy to find as a lot of inboard motors use them as well as the D16.
A friend of mine owns a 1961 century which has done a real lot of hours and he has always run the D16, he uses it to push his old mirror 16.
the champion plugs seem to be bested suited to the seagull.
In australia the plugs can be found at your local REPCO agent, so australians
don't get ripped off on ebay.