I am going to look at a bass boat tomorrow with a 2009 Mercury 115hp OptiMax on it. I am wanting to do a compression test while I am there and planned to swap the spark plugs out while I was at it (assuming the test passes and I purchase).

 

I am having a hard time finding any solid documentation on the spark plug type and how many spark plugs it uses. Does anyone know? I think it uses IZFR5J model plugs and I think it neds 6 of them, but I wanted to make sure before I purchased.

 

Also, I was reading about the bottom 2 spark plugs on the OptiMax motors being hard to reach due to the lower cowling (without removing it). Does anyone know if this is the case with the 115hp model or only on the 150hp+?

Only a bass fisherman's autocorrect changes "needs" to "neds."

Just now, Glaucus said:

Only a bass fisherman's autocorrect changes "needs" to "neds."

Haha. Nice "catch". Any advise on the motor?

2 hours ago, KeepinItReel said:

Haha. Nice "catch". Any advise on the motor?

Unfortunately not. I fish from the bank and yak. I hope you get your answer.

The 75-115 Optimax only has three spark plugs, I didn't have to remove the bottom cowling to change the spark plugs on my 90 hp. 

According to this MANUAL it uses 3 of these:

IZFR5J

115 Optimax is a 3 cyclinder 2 cycle. Merc also makes a 115 inline 6 cylinder 2 cycle, it's not the Optimax engine. The Optimax should have a computer to record operation hours at rpm hours run along with any recorded service performed.  Try to get a history report.

Tom

Thanks everyone. I got there and it was 3, they were very easy to access so I did not have to deal with the lower cowling. The compression test also was successful, all at 90. I ended up passing on the boat though. It was in way worse shape than it looked in the photos online.