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SPARK PLUG SHOWDOWN - YAMAHA SPEED TEST!!

Not surprised in those results at all.

Nice video!
 
Thanks for watching!
 
Good job Leon. A bit disappointing but not surprising really. How much did you pay for the iridium plugs? I paid $8 for the stock plugs at the local Yamaha dealer
 
Cliff notes? Don’t really like watching videos.
 
In most boosted applications (automotive), I have experienced performance increases, or at least enhanced consistency from copper tipped plugs. They wear fast, and need replacing often. In the automotive world this frequent replacement is on the order of 15-25k miles or so. Probably close to the equivalent of once a season in the marine environment. Iridium coated plugs are nothing more than a wear resistant coating developed by the automotive sector to allow for extended service intervals.

Anyone ever run an MSD box on a Yamaha? I had exceptionally good experiences with them in high boost applications in the automotive segment. Often times completely remedying previous misfire issues, and allowing to run a higher gap and more timing under boost with reliable spark. Would be curious if there is any benefit here, despite the already robust coil on plug setup on our engines.
 
Cliff notes? Don’t really like watching videos.


Great video Leon. As for the cliff notes, Iridium plugs didn't impact performance in a positive way. If anything, Leon experienced poor performance, aside from a multitude of other variables. He also point out something those of us who used to fog two stroke engines knew, fogging will increase the chances of a fouled plug. So annual changes may be recommended after a tank of fuel has been burnt in the spring. Leon's take was more succinct, if you fog, expect to change your plugs.

My question is, did you change your plugs while yours were in good shape just for the sake of a performance comparison? Otherwise, if I owned an SX190, that was pulling nearly 50mph, the thought of changing my plugs would never cross my mind.

For the same reason in my 242LS, if she is pulling 50+ mph with similar RPM's on both motors, I keep them in, and wait for RPM drops to worry about changing plugs. I have them on hand, in case it happens.
 
Good job Leon. A bit disappointing but not surprising really. How much did you pay for the iridium plugs? I paid $8 for the stock plugs at the local Yamaha dealer
To be honest I don't recall. They were only slightly more money than the copper plugs. Maybe $11 each? Don't quote me on it. Thanks for watching!
 
I wonder what impact the iridium plugs would have on the occasional hard to start issue that sometimes plagues the Yamaha jet boat motors after a long hard run.
 
I wonder what impact the iridium plugs would have on the occasional hard to start issue that sometimes plagues the Yamaha jet boat motors after a long hard run.
Wonder no more, the random hard start has plagued me for my whole 8 seasons of ownership, it continued with the iridiums, sadly.
 
Wonder no more, the random hard start has plagued me for my whole 8 seasons of ownership, it continued with the iridiums, sadly.

Dang it!!!
 
Interesting did not know you should not gap iridium plugs. I always gapped them.
 
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