Best way to get fuel flow readout from 2004 F90??

[scoutabout]

Hey guys - would love to add a fuel flow gauge of some sort to my 90 Yamaha 4 stroke. I've been reading online about these things but am a little confused. Some engines appear to output this info through (NEMA 2000?) connectors under the cowl, others seem to require inline fuel flow sensors, still others need an onboard network setup, many systems are stupid expensive....I'm just looking for a small readout in the dash. No chart plotter, autopilot or other fancy stuff on this boat.

So...question 1 I guess is, does anyone know if my motor generates this data? Being a 2004 model, it's one of the last of the multi carb pre-FI motors so I'm thinking maybe not.

This would make question 2....can anyone suggest a simple, reliable, reasonably priced package of sensor and gauge?

Thanks!

 

[Scott Danforth]

if you got a carb and not EFI, then no, you wouldnt have an engine ECM reading sensors and sending data down the J1939 CAN BUS (NEMA 2000)

your going to need an in-line flow meter and a gauge that reads is.

my question is why does it matter? your motor burns 9gph at full load. any RPM below WOT and your fuel consumption varies with way too many conditions to ever worry about it.

 

[scoutabout]

Thanks for the confirmation of data availability Scott.

As for the 'why'? Just cuz. I like to understand what factors affect fuel consumption and by how much. Loads in and behind the boat, winds, state of tune, temp, types of fuel, trim angle, rpm, etc, etc. Nerd stuff. Plus 9gph is 34 litres per hour for me. There's quite a range in there. Maybe I'll discover that a certain trim setting saves me a litre or two an hour for instance. Might be a tank of gas over a season or two. pay off that flow gauge... Plus, I'm an instrument junkie. The more the merrier and I have a spot for it.

 

[99yam40]

find something like your setup here to see what prop and RPMs got the best economy.

https://yamahaoutboards.com/en-us/home/owner-resources/all/performance-bulletins

 

[Scott Danforth]

Ithe issue with economy and boating is that they are on opposite ends of the spectrum.

As far as savings go, the gauge may pay for itself in 10 years of recreational boating. I usually will have replaced the boat by then

 

[scoutabout]

99yam - awesome, thanks! That's a fascinating chart and demonstrates the kind of info I'd suspected but wanted to see. (Still want the gauge for my own exact setup, tho). Very cool to see things like - between 2500-3500 rpm, fuel burn almost doubles, but between 3500-4500 it goes up incrementally....before the curve heads uphill more sharply again between 4500-5500...