Welcome, Guest
Username: Password: Remember me
  • Page:
  • 1

TOPIC: 3988 actual fuel capacity

3988 actual fuel capacity 19 Jul 2017 14:28 #1

  • scubadiver#3988
  • scubadiver#3988's Avatar Topic Author
  • Offline
  • New Member
  • New Member
  • 1997 #3988
  • Posts: 54
  • Thank you received: 1
I drove the boat from Morro Bay, Ca to Monterey, Ca. According to the GPS 116 miles. This is the 3rd trip taken of some distance. The most I have filled either tank is 96.3 gallons. Last trip the port tank accepted 96.3 and the starboard 90.8 (gen runs off port). I am beginning to question the capacity of the 3988 tanks or my gauges. After each trip the gauges read below E.
Bayliner lists 150 gallons per tank. I measured the port tank (56L x 31h x 16w) and calculated 124 gallons. Either Bayliner is wrong or my fuel senders are wrong.
Has anyone ever filled the tanks of a 3988 with more than 124 gallons?

Before my next fill up, I was considering pumping the balance of one tank to the other. Is this a wise decision? or am I asking for trouble?
It would let me know actually how much the tank holds.

Please Log in or Create an account to join the conversation.

3988 actual fuel capacity 19 Jul 2017 14:56 #2

  • smitty477
  • smitty477's Avatar
  • Offline
  • Platinum Member
  • Platinum Member
  • Posts: 5741
  • Thank you received: 966
On top of each tank is a tag about 2" by 3" that tells you the volume, dimensions and tank thickness.
Sometimes it is difficult to access this tag so maybe you can use a cell phone to take a picture to read it.

The gages read a resistance value off of a variable resistor mounted at the attachment of two arms that for a "V" when they are working to show depth/volume.
Often they are 'set' off incorrectly and show less volume than exists - this is safer that the other way around. Also they tend to wear and not read too well or 'skip' from 1/4 or so to empty when they get old and well used.
When installing a new gage you can 'set' the new sender so that it reads whatever you want at mid height or at low height but be careful you know what you are setting it for as you do not want to run out of fuel.
I set them based upon depth before they get 'wet' with fuel so that they read 'empty' with about 1/8th tank left - my choice only not necessarily the best one for you.

Please Log in or Create an account to join the conversation.

Northport NY

3988 actual fuel capacity 19 Jul 2017 15:01 #3

  • smitty477
  • smitty477's Avatar
  • Offline
  • Platinum Member
  • Platinum Member
  • Posts: 5741
  • Thank you received: 966
BTW- I am not familiar with the 3988 tanks but many of the other Bayliners have tanks that are not a rectangle.
So one side or more may have a deeper end than you have access to or have the ability to measure.

Please Log in or Create an account to join the conversation.

Northport NY

3988 actual fuel capacity 19 Jul 2017 15:06 #4

  • smitty477
  • smitty477's Avatar
  • Offline
  • Platinum Member
  • Platinum Member
  • Posts: 5741
  • Thank you received: 966
" I measured the port tank (56L x 31h x 16w) and calculated 124 gallons. Either Bayliner is wrong or my fuel senders are wrong.
Has anyone ever filled the tanks of a 3988 with more than 124 gallons?"

Again FYI only - When I figure these dimensions I get 120 gallons.

56 X 31 x 16 / 231 = 120 gallons

Please Log in or Create an account to join the conversation.

Northport NY

3988 actual fuel capacity 19 Jul 2017 15:32 #5

  • The Other Gary
  • The Other Gary's Avatar
  • Offline
  • Platinum Member
  • Platinum Member
  • Posts: 1242
  • Thank you received: 130
I had a fuel truck in last week. my gauges showed 10% port and 15% starboard.
I took 222 gallons and only filled to 90% to avoid spillage.
I have the accu-gage system and recently removed the probes to set the empty reading then filled to set the full reading.
Seems pretty much correct as 77.5 % of 298 gal is 230 gal.
The following user(s) said Thank You: smitty477

Please Log in or Create an account to join the conversation.

"Adios Dinero"
1997 3988 with new 330 Cummins
Photo Credit: Whiskywizard
Last Edit: by The Other Gary.

3988 actual fuel capacity 19 Jul 2017 16:26 #6

  • Uncle Bob
  • Uncle Bob's Avatar
  • Offline
  • Platinum Member
  • Platinum Member
  • Posts: 1721
  • Thank you received: 132
"gen runs off port" are you sure? Mine runs off stbd. You can check the old fashioned way and pull the sender and use a yardstick to see how deep the tank is and how much fuel is there. Then compare to the gauge.

Please Log in or Create an account to join the conversation.

1989 26' then 1994 32' now 2001 39'

3988 actual fuel capacity 19 Jul 2017 16:36 #7

  • The Other Gary
  • The Other Gary's Avatar
  • Offline
  • Platinum Member
  • Platinum Member
  • Posts: 1242
  • Thank you received: 130
The manifold under the center deck hatch in the salon allows switching any tank to any engine including the genny. and also allows redirecting the return lines.
Measuring the fuel sender travel against the known depth of the tank is also a good idea.

Please Log in or Create an account to join the conversation.

"Adios Dinero"
1997 3988 with new 330 Cummins
Photo Credit: Whiskywizard

3988 actual fuel capacity 19 Jul 2017 17:02 #8

  • Uncle Bob
  • Uncle Bob's Avatar
  • Offline
  • Platinum Member
  • Platinum Member
  • Posts: 1721
  • Thank you received: 132
My 2001 doesn't have the manifold but does have shut-offs and a fuel transfer pump.

Please Log in or Create an account to join the conversation.

1989 26' then 1994 32' now 2001 39'

3988 actual fuel capacity 19 Jul 2017 20:18 #9

  • The Other Gary
  • The Other Gary's Avatar
  • Offline
  • Platinum Member
  • Platinum Member
  • Posts: 1242
  • Thank you received: 130

Uncle Bob wrote: My 2001 doesn't have the manifold but does have shut-offs and a fuel transfer pump.


That's too bad that they deleted the manifold for your model year.
In my opinion it is the best for fuel management, ballast management and by adjusting the return line settings you have three engines that can transfer fuel instead of relying on a single pump that will let you down right when you need it.

Please Log in or Create an account to join the conversation.

"Adios Dinero"
1997 3988 with new 330 Cummins
Photo Credit: Whiskywizard

3988 actual fuel capacity 19 Jul 2017 23:57 #10

  • kev_rm
  • kev_rm's Avatar
  • Offline
  • Senior Member
  • Senior Member
  • 1987 3870 Hino 175's
  • Posts: 236
  • Thank you received: 31
ok sorry you are basing your estimate of capacity off the gauges? Use a stick ;)

Please Log in or Create an account to join the conversation.

3988 actual fuel capacity 20 Jul 2017 15:32 #11

  • Uncle Bob
  • Uncle Bob's Avatar
  • Offline
  • Platinum Member
  • Platinum Member
  • Posts: 1721
  • Thank you received: 132
I don't miss the manifold. Had 'em, never used. Do use the transfer pump. BTW, I witnessed the results of a manifold switched to both engines to one tank last week. Skipper forgot and filled the club with diesel through the vent. Lucky he wasn't caught for a big fine.

Please Log in or Create an account to join the conversation.

1989 26' then 1994 32' now 2001 39'

3988 actual fuel capacity 25 Jul 2017 15:44 #12

  • Grafty
  • Grafty's Avatar
  • Offline
  • Senior Member
  • Senior Member
  • Posts: 141
  • Thank you received: 10
I owned a 3988 for over two years and never found the gauges to be accurate or to be dependably inaccurate. Knowing how much fuel I have is a big deal. I ended up using a fuel stick calibrated for each tank. The 3988 has good access to add a port in the top of the tank to drop a calibrated stick into the tank from inside the salon. At the rear end of each tank there is a sending unit location. I removed the sending units and drilled a hole next to the sending unit access hole large enough to put in a fitting (AN bulkhead fitting) that had a backing nut inside the tank and a removable cap. I was able to use about a 3/8" wooden dowel rod with graduated markings. Access to this area is thru the carpeted small hatch on the starboard side and a corresponding hatch under the couch on the port side. I found that 1" on the stick represented almost exactly 5 gallons. After some experimentation under actual filling conditions, I was able to predict the amount of fuel I took on to within 5 gallons using the sticks. Poor mans flow scans

Please Log in or Create an account to join the conversation.

Bob and Lulu
1997 5788 'Starship' MAN 610s
1996 3988
1993 3058
Vida, Oregon

3988 actual fuel capacity 26 Jul 2017 15:52 #13

  • Uncle Bob
  • Uncle Bob's Avatar
  • Offline
  • Platinum Member
  • Platinum Member
  • Posts: 1721
  • Thank you received: 132
Thanks are labeled 148 gal each.

Please Log in or Create an account to join the conversation.

1989 26' then 1994 32' now 2001 39'
  • Page:
  • 1
Moderators: higgins_jrJim Gandee
Time to create page: 0.104 seconds
Powered by Kunena Forum