2021 R5 fuel gauge

(R3-R8, R30, R35)
Post Reply
Pete12
Ensign
Ensign
Posts: 15
Joined: Sun Aug 06, 2023 6:47 pm
Location: NY
Contact:

2021 R5 fuel gauge

Post by Pete12 »

Been having trouble with fuel gauge. Often it reads full when I know tank is not full. To remedy I've started using the fuel used and total fuel remaining gauges on the glass cockpit. To check accuracy I marked level on fuel tank added 15 gallons of gas. When fuel used gauge read 15 gallons I rechecked tank and level was just about on mark. Seems pretty accurate. Now when I add gas, i just enter amount into the glass cockpit.
Anybody else using thise gauges?
User avatar
stifflkd
Captain
Captain
Posts: 362
Joined: Fri Dec 18, 2020 9:29 pm
Location: Brick, NJ
Contact:

Re: 2021 R5 fuel gauge

Post by stifflkd »

What engine make do you have. The VP's have two calibration processes you do at the EVC. I did the Full Fuel Calibration (the simplest) and it is fairly accurate.
2021 R5 Shale/Ebony
VP 5.3L 350
"$TSLA"
User avatar
bruceb58
Vice Admiral
Vice Admiral
Posts: 1256
Joined: Tue Nov 24, 2020 11:10 pm
Location: Lake Tahoe
Contact:

Re: 2021 R5 fuel gauge

Post by bruceb58 »

On our R5 with a Mercruiser, it reads full for a long time. Based on fuel used, it is pretty accurate when around half full. As the tank empties, the gauge appears lower than it really is.

I go by fuel remaining. It seems VERY accurate.
2017 R5 350HP Mercruiser Bravo III
Northridge, CA
Big Bear Lake, CA
South Lake Tahoe, CA
JC522
Lieutenant
Lieutenant
Posts: 25
Joined: Thu Aug 15, 2024 9:24 am
Location: Lake Michigan
Contact:

Re: 2021 R5 fuel gauge

Post by JC522 »

You can correct the inaccuracy by adding a resistor to the sender circuit. The sender typically has a resistance of 30 ohms at full and 240 at empty, for a range of 210 ohms. If the gauge is reporting 10% too high, theoretically you would add 21 ohms. Try adding 15 and see if you like the results. If it is reporting too low, you have to add a resistor in parallel and the math is a little more complicated.
JC522
Lieutenant
Lieutenant
Posts: 25
Joined: Thu Aug 15, 2024 9:24 am
Location: Lake Michigan
Contact:

Re: 2021 R5 fuel gauge

Post by JC522 »

You can correct the inaccuracy by adding a resistor to the sender circuit. The sender typically has a resistance of 30 ohms at full and 240 at empty, for a range of 210 ohms. If the gauge is reporting 10% too high, theoretically you would add 21 ohms. Try adding 15 and see if you like the results. If it is reporting too low, you have to add a resistor in parallel and the math is a little more complicated.
User avatar
Krob1114
Vice Admiral
Vice Admiral
Posts: 1874
Joined: Sun Jun 09, 2019 8:03 am
Location: Greer’s Ferry Lake, AR
Contact:

Re: 2021 R5 fuel gauge

Post by Krob1114 »

I didn't notice the remaining fuel option on our Garmins. We're making a trip to the lake in a few hours, and I'll check.
2019 Cobalt R3 @ Greers Ferry Lake, AR
Home in Hernando, MS
Post Reply

Who is online

Users browsing this forum: No registered users and 2 guests