Spark Plugs

[Supraman]

What plugs is everyone using? Cheap coppers or expensive Iridium?

I typically put 100-125 hours on my SX per season and would prefer to not have to do a mid season swap. I did a search of the forums, but didn't find any conclusive answers.

Any input on brands & types is appreciated.

Thanks,

Mike

[Supraman]

Amazon has the BOSCH Part # 4501 PLATINUM IR FUSION which is spec'd for the 1999 Lexus SC400 for $5.82 each. Plus a $4 per plug mail in rebate... This brings the cost per plug down to $1.82... Anyone tried these?

[tryme]

i just ordered 8.  i had a 10 gift card to amazon so it will cast me $4 total with shipping.  even if they are just a good spare you cant go wrong.  they are iridium and work in the ls400.  works for me.  the ice is finally off the lake i am strapping on the dry suit and skiing over mothers day weekend.  wish me luck!!

[ATXChris]

I had Bosch Iridium plugs in my E21 last year and started having drivability issues early this season so replaced them with cheapo Bosch copper old school style plugs.  Boat is running great now.

There's a post in one of the other threads that mentions the iridium plugs being more prone to fouling.  Can anyone confirm this ?

[wakejunky]

just from experience. I never put anything but denso or ngk in anything especially Toyota and Lexus.

also from experience the iridium will foul faster due to the small electrode. iridium is designed for 120K mileage intervals in a closed loop fuel system. we do not have a closed loop fuel system (no o2 sensor feedback). plus we run a 160 degree thermostat that makes our boats run rich. Rich makes good power but also fouls plugs especially if your using anything other than 91 or higher octane. My secret is to run factory denso sparkplugs for a 2000 or so model year Toyota tundra 4.7 liter. They are less than $2 a plug from the dealer. they are a standard plug with a much larger electrode area. I've ran the same set of tundra plugs in my epic for 2 years with no problems. Just put a fresh set in because I'm selling it.

why spend money on iridium or platinum if your going to change them every year or so.

[DENNIS]

+1 on the tundra 4.7 motor plugs.

Dennis

[liljulzs]

Wake Junky, do you still use the same plugs? I'm looking for the part.

[IndianaEPIC21]

I use the Denso 4.7 Tundra Plugs and runs great.

[liljulzs]

Are they Platinum? Iridium or Copper?

[wakejunky]

Hi, sorry for the delay, I don't log on like I used to. Don't have the epic or anything else at the moment, but that doesn't change my opinion. As per 5 minutes ago current part # is 90919-01166 . Copper plug, less than $2 at my dealership. I wouldn't run anything else, for the price why would you. Have a Great weekend.

[cyclone]

Thanks Wakejunky, appreciate your participation and knowledge. I just ordered a set of those Denso plugs, it does seem that the iridium plugs foul a lot. According to Rick, if they foul and you get detonation as a result it can cause exhaust manifolds to fail. Good reason to swap them every year.

[liljulzs]

Thanks WakeJunky! I'm ordering now. This saved me. Each time I look for the Tundra 4.7 plugs they are not Copper. Phew! Glad I waited!

[jwilcox]

Capt Rick turned me on to the Autolite 3923's with .43 gap. They have been great so far.  $1.12 on Rock auto or $2.97 at the local parts store. I had them in for one season and the electrode is worn somewhat and there is lots of... stuff on it.

I am a piece of mind guy and a dirty MAF and bad plugs make this boat feel like there is really something wrong with it, when its just an easy fix. Clean the MAF frequently with MAF cleaner, swap the plugs out and and no issues!

[liljulzs]

Thank you. I ended up buying the ones from Toyota dealership. They are $2.20 a piece. I swear last year I just have spent $8-9 a plug. Didn’t feel better.

I need to learn how to clean the MAF myself. Is it hard?

[jwilcox]

No, it is two 10mm bolts.

Unclip the wiring harness and hit it with some MAF cleaner (do not hit it with any other cleaner).

I clean mine pretty regularly and do plugs once a season and it runs great. If I let the boat sit, dust gets on the MAF and it runs bad.