Spark plug problem 150 HP

[dailey]

"I have a 150 HP with about 70

"I have a 150 HP with about 70 hours total run time. About a month ago I had a very serious miss develop in the engine ( would not get on plane ). I took the boat to the dealer, they informed me that there were no trouble codes indicated, and that the problem was a bad plug (Denso skj20dr-m11) and that honda would replace under warranty due to lack of hours. Yesterday while heading across the lake the engine developed a serious miss and would not stay on plane. I idled back home and found that the top cylinder was not firing, replaced the Denso plug with a NGK I had purchased (IZFR6K116994) PROBLRM WENT AWAY.

My questions are:
Is there a problem with some of the IRIDIUM plugs, or my engine ??
What plug do you recommend?

I do not know which of the four cylinders the dealer replaced the plug on---

Do you have any suggestions?

Also --- I have performed the 20 hour oil and filter change. I plan to use Castrol syntec for the next oil change ------- I tried to perform a search on this subject ---but could not find any definite information pro or con."

 

[chawk_man]

"DD - I never used the Denso p

"DD - I never used the Denso plugs. But, there is no way they should fail with only 70 hours. In my 2007 BF225 I use the same NGK 1ZFR6F11. I've always had good experience with the NGK's on this and all my previous engines. As for using a synthetic oil - don't waste your money unless you are operating in very, very cold or very, very hot climate - spend it on the oil filters. I change the oil AND the filter every 100 hours. Manual says change the filter every 200 hours, but I just don't like that idea and change the filter every time I change the oil, just as I do with my auto engines. Don't even think about using a synthetic to extend the times between oil changes. Change it every 100 hours regardless of what type oil you use."