F115 Differences

[Jersey Jim]

I have a 2002 F115 TXRA and was trying to look up performance bulletins on this motor with an 1801 CC. Yamaha only had two tests done on this boat with a 115 hp. However, all conditions seemed identical yet the mpg dropped from 5.82 with a F115 TXRZ in a 2001 test, to 4.82 mpg with a F115 TLR in a 2006 test. My question is, what is the difference between a TXRZ and a TLR? Also, what is the difference between my TXRA and the TXRZ in the test? All props, gear ratios, weights, etc. were the same yet I don't understand the 17% reduction in fuel economy.

Thanks,

Jim

 

[tbone65]

The Yamaha model designators tell you a few things: the TXRZ is a 25" shaft, 2001 model year motor. The TLR is a 20" shaft, and most likely a 2006 model, as Yamaha abandoned the model year designator digit (the final letter inthe model number) after 2005.

Everything about those two tests doesn't add up to a large difference in fuel burn, however...if anything, the 25" motor seems very effecient...can't see any reason that the newer, 20" motor should burn almost 5 GPH more than the 01 model at WOT....very strange numbers.

 

[Jersey Jim]

Tim, thanks for clarifying the Shaft and year designator in the model number. I wasn't clear when I explained it, but the 2006 TLR got 4.86 mpg and the 2001 TXRZ got 5.83 mpg. The TXRZ got 1 mpg more, or about 17% better.
I was hoping to determine by this posting, which of the two tests came closer to matching the performance of my 2002 F115 TXRA.

Jim

 

[tbone65]

Model for model, (both 25") and being only 1 year apart, I would think that the TXRZ numbers should be closest to your 1 year newer motor.

But again, those to sets of figures don't fully make clear sense to me. I still can't see the newer, 06 20" motor burning so much more fuel than its 6 year old counterpart.