Fuel Flow meter results W/ GPS speed

79Merc80

Senior Chief Petty Officer
Joined
Nov 22, 2007
Messages
673
Hey Guys. Here is what my Fuel Flow Meter (Flo-Scan) gave me this morning at 500RPM intervals with speed. I'm not sure the RPM portion of the guage is set correctly as WOT sounds a lot faster.


RPM ----------- GPH ---------- MPH
580 ------------ 1.0 ----------- 4.0
1010 ----------- 1.8 ----------- 6.0
1510 ----------- 3.4 ----------- 9.0
2020 ----------- 4.2 ----------- 18
2500 ----------- 5.4 ----------- 24
3000 ----------- 7.0 ----------- 31
3500 ----------- 9.7 ----------- 35
3620 ---------- 11.4 ----------- ??


This is from a 1984 Mariner 90hp inline 6. I don't know how fast I was going at WOT as the GPS speedo only goes up to 35.

Let me know your thoughts on this.

Thanks. Craig
 

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79Merc80

Senior Chief Petty Officer
Joined
Nov 22, 2007
Messages
673
Re: Fuel Flow meter results W/ GPS speed

I contacted Flow-Scan and there is an adjustment to the tach. It now reads 4900-5000 at WOT. Next time out I will do the same test with the correct RPM intervals.

Craig
 

79Merc80

Senior Chief Petty Officer
Joined
Nov 22, 2007
Messages
673
Re: Fuel Flow meter results W/ GPS speed

Ok, here are the corrected results

RPM ---------- GPH ---------- MPH
0620 --------- 1.3 ----------- 3.0
1000 --------- 1.6 ----------- 4.5
1500 --------- 2.3 ----------- 6.0
2000 --------- 3.6 ----------- 8.0
2500 --------- 4.3 ----------- 12
3010 --------- 5.1 ----------- 21
3510 --------- 6.1 ----------- 26
4000 --------- 7.2 ----------- 30.5
4510 --------- 8.8 ----------- 35
4820 -------- 11.5 ---------- 39

3500 seems to be the most efficeint speed. And this run was with 2 other people in the boat
 

BaileysBoat

Senior Chief Petty Officer
Joined
Sep 29, 2008
Messages
716
Re: Fuel Flow meter results W/ GPS speed

What hull are you pushing with the Mariner? Seems like the sweet spot is just up on plane, 4.26mpg.
For comparison sake I get 5.35 mpg at 3500 RPM with the F150 on my Islander 19.
 

79Merc80

Senior Chief Petty Officer
Joined
Nov 22, 2007
Messages
673
Re: Fuel Flow meter results W/ GPS speed

I'm pushing a 17' Fiberform (1979) Wikiki.

Craig
 

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