2021 SX195 Spark Plugs

[Moreyrd]

All, I am looking for help in what are the proper spark plugs to purchase for my Sx195. I have the service manual and the page has the following:

"Spark Plug (NGK)
LFR6A (TX1800A-U, TX1800B-U)
LFR7A (TP1800A-U, TP1800B-U)

Spark Plug gap....."

Does this mean that either LFR6A or LFR7A will work? My guess is that the TX or TP#'s indicate which is correct for my boat. Can anyone help?

Thank you

 

[Michal]

@Moreyrd you will need the 7A for the supercharged engine.

 

[Moreyrd]

@Moreyrd you will need the 7A for the supercharged engine.

Thank you Michal,

Curious, do you happen to know what the TP1800<letter> refers to?

 

[Michal]

Thank you Michal,

Curious, do you happen to know what the TP1800<letter> refers to?

I'm pretty sure it has to do with the 1.8L engine type, but I'm guessing here.

 

[Moreyrd]

I'm pretty sure it has to do with the 1.8L engine type, but I'm guessing here.

Thanks again, that makes sense.

 

[Thermobrett]

These are the plug I use in my 2022 SX195
NGK Iridium IX Spark Plug LFR7AIX # 2309 PK4 https://a.co/d/8UbLudU

 

[Moreyrd]

Thank you

 

[Thermobrett]

Thank you

Just note you do NOT need the iridium plugs, but the cost was only Pennie’s more per plug (at the time I purchased) so I went with these opposed to the standard plugs. Some sites have the oil change kit + plugs as a “bundle” package so you could always go that route too for your yearly maintenance interval.

 

[212s]

Curious, do you happen to know what the TP1800<letter> refers to?

The "TP1800" number simply refers to jetski models as these plugs are used in the same engines in Yamaha Waverunners. As mentioned, the 6A is for the regular 1.8L motors, and the 7A is for the supercharged 1.8L motors. Iridium plugs are for extended mileage use in vehicles to increase plug change interval periods. There is no reason to use them in our boats, especially if they cost more.

Also you don't need to change your plugs unless they're worn or malfunctioning (internal arcing causing rough engine operation or misfires) with the 1.8L engines. You only need to check them every 100 hours to confirm they're in good condition and proper colour which indicates fuel/air mixture is good, and to confirm the spark gap is still within spec. As the plugs wear, the electrodes will wear some of the material and the gap increases. Once the gap is beyond spec max of 0.9mm, they need to be replaced. The plugs should not be adjusted as it will weaken the ground electrode weld and could cause failure. Plugs today are pre-gapped at the factory to meet specs for their intended use. As an example, I just hit 201 hours and pulled the original factory installed plugs to check them again yesterday. They have good colour and gap is still within spec at about 0.86mm with some normal wear in the center of the ground electrode. Engines ran good but I decided to change them out with new plugs and keep a pack of 4 old ones for spares, but otherwise they'd be good for another 100+ hours of use before the ground electrode wear gets excessive causing a larger spark gap. Gapping tools won't account for wear in the center of the ground electrode so using a magnifying glass or photos to inspect helps to see the wear.

As a rough comparison, 100 hours on your boat is like 18,000 miles in your vehicle = 100 hours x 60 mph x 3 (higher revs 1800 vs 6000 rpm) on average. That's not a lot of mileage for these plugs where about 50,000 miles would be expected which is roughly 250-300 hours depending on how you run your boat. As long as the plug is functioning properly, and fuel/air mixture is good, there's no reason the plugs shouldn't last about 300 hours or more.

Here's one of mine I just pulled - colour and wear is perfect. Click to enlarge: