gap for NGK LFR6A-11

[rickd01]

anyone know the correct gap for these plugs?

 

[beachbum]

Pretty sure it is .031 to .035 in. On the 1800 cc engine.

 

[GiddYupJoe]

@rickd01 a lot of discussion has been had on gapping the -11 plugs. Check out this thread.

https://jetboaters.net/threads/maintenance-time-pix-of-the-products.2570/

The LFR6A is what you want. This is also a quote copied from @txav8r from a separate thread.

"This is the wrong spark plug for the 1.8L engines. It takes an LFR6A, not the LFR6A-11. The -11 is cheaper, and it is not the right length electrode, gapping to .8 to .9mm stresses the metal and it can break. NGK does not recommend doing this. But some dealers as well as members buy them anyway because they are cheaper. My selling dealer incorrectly sold me these and I made them take them back and refund my money. And Advance auto as well as O'Reilly's don't stock the 6A but they will get them for you".

 

[txav8r]

I spoke directly to NGK, they don't intend the -11 to be gapped as tight as we need. They caution the arm could break bending it that far.

 

[rickd01]

@rickd01 a lot of discussion has been had on gapping the -11 plugs. Check out this thread.

https://jetboaters.net/threads/maintenance-time-pix-of-the-products.2570/

The LFR6A is what you want. This is also a quote copied from @txav8r from a separate thread.

"This is the wrong spark plug for the 1.8L engines. It takes an LFR6A, not the LFR6A-11. The -11 is cheaper, and it is not the right length electrode, gapping to .8 to .9mm stresses the metal and it can break. NGK does not recommend doing this. But some dealers as well as members buy them anyway because they are cheaper. My selling dealer incorrectly sold me these and I made them take them back and refund my money. And Advance auto as well as O'Reilly's don't stock the 6A but they will get them for you"

 

[rickd01]

thanks @GiddYupJoe for the reference, I swear I did do a search for that before asking the Q. I got the plug info from yamahasportsplaza.com. I have bought parts from them in the past and they have been correct.

 

[txav8r]

The thing is, Yamaha spec'ed the LFR6A, not the LFR6A-11. Some Yamaha dealers view them as the same and sell them as a stock plug. My selling dealer did that very thing when I took delivery. I purchased at cost, some basic tune up supplies and toys that was included in my deal. They gave me the -11's. When I got home, I started researching to find out why they said -11. First thing I did was call the dealer, and they swore they were the right plug. I googled the plugs and saw there was a difference in electrode and arm size. So I called NGK USA and talked to a tech. He told me that the -11 arm bent far enough to close to the correctly spec'ed gap for the Yamaha would risk breaking the weld, and at best it would strain it, and not be reliable in maintaining the gap under temperature changes. He said that is why they make so many different plugs, because they have different applications. My next question was why does two almost identical plugs, have such a different price. He said it would be marketing he was sure, but that wasn't his department. But he added that they manufactured many more -11 plugs than the standard plug, and that due to volume alone, that the price could be affected greatly.

IMO, no more often than we change these plugs, I don't think quibbling over $10 per year is worth the risk of a poor running engine or worse. But this is another perfect example of why we don't just take the word of a dealer, that hasn't done the leg work to verify something so simple. The best source of information on the planet for these boats is right here at JETBOATERS.NET. And it isn't because I am so smart, it is because we as a community do that kind of research and have a combined knowledge that Yamaha often listens to, and makes changes based on that field experience. Anyway, if you installed the -11 in the past, even I wouldn't change them off schedule, I would wait until time and then use the correct LFR6A.

 

[BoaterGuy]

I purchased the -11 plugs and gapped them using the special gap tool:
http://shop.advanceautoparts.com/p/..._d_c_v__vi__&gclid=CPjUt9C98cUCFUQXHwodmRcAhA

I had no running problems but ultimately switched back to the correct non -11 plugs the next season. For the price difference, it's not worth risking having problems down the road.

I think the correct gap is .032

 

[Geiger41]

so these are the ones for the 1.8's...

http://www.amazon.com/NGK-LFR6A-Standard-Spark-Plug/dp/B001RMCB7A

 

[GiddYupJoe]

@geiger41 those look to be the correct plugs.

I did quite a bit of searching when I purchased mine and can confirm that these are the exact plugs you need at the best price. $4.32 ea.

http://www.race-mart.com/NGK-NGK-LFR6A.html

 

[Geiger41]

The shipping on that eliminates the best price option for me. I remembered a guy I work with owns www.cheapassracing.com so he is going to get them for me (Awaiting "My" price).....If anyone has a group buy of anything mechanical for the engines let me know. He would set something up if it was worth while.

 

[B_Mutter]

The reason why we dealers stock the -11 plug is because it is used in the Outboards VF150, F200, F225, VF200/225/250, F225CA/250CA/300CA, F225 sport, F250/250B, F350 so that is why NGK sells more of those than the standard plug. We actually stock both plugs and have to label all the boxes. It's gets a little confusing with the amount of spark plug numbers we have in stock.

 

[beachbum]

I have been to two yamaha dealers... they both offered only the -11 plug. I have installed the -11 this season. This discussion leads me to believe I'll be doing some cha cha changin'.

 

[InmyElement]

So did we figure out the gap on the correct plugs?

 

[Guy in a Boat]

.8-.9mm for LFR6A. Most little plug gap guages now have metric on the reverse side if you are looking at the disc type. Your valve covers come with the catalyst on the cover.