View Full Version : '08 LSV GIII upgrade to Johnson Pumps

09-12-2011, 02:54 AM
So I finally finished my Johnson Reversible Pump Ballast Upgrade from GIII on my 2008 LSV. I had previously followed Fman’s Tsunami upgrade and it just didn’t work well for me. I know it can be done well as others here have, but I just couldn’t get it right. This is also my first attempt at a “How To” thread so please bear with me and let me know what I could do to make it better for next time. (Newty I kinda used some of your threads as a template, hope you don’t mind.)

Resources included:
Jester’s – “GI to GIII with reversible pumps, 08 OBV” (https://forum.moomba.com/showthread.php?16130-GI-to-GIII-with-reversible-pumps-08-OBV&highlight=jester)

My thread to ask questions from our great and knowledgeable members. – “Reversible ballast pump locations on '09 or newer LSV?” (https://forum.moomba.com/showthread.php?16271-Reversible-ballast-pump-locations-on-09-or-newer-LSV&highlight=reversible+pumps)

And of course Jason at Wakemakers.com (http://www.wakemakers.com)

Parts I ordered from Wakemakers.com:

4 – Johnson Ultra Ballast Reversible Pumps
3 – 1” Bronze Thru-Hull Intakes
1 – ¾” Stainless Steel Barbed Thru-Hull (For the new IBS vent)
3 – 1” Bronze Ball Valves
3 – 1” Thread x 1” Hose Barb Fittings
1 – ¾” Thread x 1” Hose Barb Fitting (Goes into the ¾” Ball valve that came stock on my boat as I am reusing it.)
4 – Fly High 1” Flow-Rite Quick Release Connect W743
4 – Fly High 1” Elbow Flow-Rite Quick Release Connectors W746
Plugs for the unused drain holes in you bags.
50ft – 1” Ballast Hose Black
14 - 1” Stainless Steel Hose Clamp (Just buy them from Lowe’s or wherever. The ones from Wakemakers broke with the slightest pressure applied to tighten them.)
15ft – ¾” Ballast Hose Black (Bought this but didn’t need it, as the ¾” thread to 1” barb worked great.)
90ft – 12 Gauge 2 Conductor Marine Pump Wire
8 – 12 Gauge Crimp Butt Connector (Order a few extra, if you mess one up you’ll have to go get another one.)
21 – 12 Gauge Female Crimp Terminal (Order a few extra also.)
1 – Extra Ballast Switch

Parts I got From Lowe’s, Radio Shack, Fry’s and West Marine:

16 - Stainless Steel Hose Clamps.
16 – Stainless Steel Round head bolts, washers, lock washers, wing nuts and nylon lock nuts. I cannot remember the sizes, just take the rubber vibration mounts and inserts that come with the pumps to Lowe’s and get ones that fit tight and are about 2” long.
25ft Roll - 14 Gauge Red Wire (Power)
25ft Roll – 14 Gauge Black Wire (Ground)
1 – 14 Gauge Fused Red Wire (comes with 30 amp fuse, but you need 20amp.)
4 – 20amp Fuses
Various sizes of heat shrink tubing for electrical connections. (Try to get the kind with adhesive lining, which is better protection for water exposure.)
Safety Glasses
3M 4200

Tools I used:

3/16” Drill bit to start the holes for the hole saw.
1 1/4" hole saw for the 1” Thru-hulls
1 1/8" hole saw for the ¾” Barbed Thru-hull used for the new vent in the starboard side of the boat.
Blue Painters Tape
Dremel Tool with a small tube-style sanding bit. (Used this to feather the holes in the hull and protect the gel coat.)
5/16” Nut Driver
Wire Cutters & Crimpers
Soldering Iron
Razor knife to cut the ballast tubing.
Cresent Wrench (12”)
Needle Nose Vice grips (I used these to hold the new intakes from inside while it was being tightened. Some people have used wrench handles and other things.)
Beer is optional…. I did it stone cold sober… Was wishing I had some beer…

09-12-2011, 02:57 AM
I decided to drill all the Thru-Hull holes first, and then I could find the best location for the pumps in relation to the new Thru-Hull fittings.

Start inside the boat and find the areas that give you the most area to work with. Measure it twice just to be sure, then take a deep breath and drill your first hole. Once done crawl under the boat and it should look something like this. If you mess up at this point it is still OK as you can easily patch a small hole. You will notice in this image that I have already grinded down the factory ¾” strainer when I did the Tsunami upgrade. There are several threads on how to do it so I will not get into it here.

Get you Blue painters tape and put a couple of pieces over the pilot hole. Bring your drill and 1 ¼” hole saw with you. Make sure to start the drill slowly in reverse or you will take big chunks of gelcoat off with the hole saw. I drilled mine half way through with the hole saw in reverse then switched to forward to finish the job.

Next pull the tape off and use the Dremel tool or drill with a small tubular sanding bit to feather/bevel the edges so the gelcoat will not crack when you tighten the thru-hull fitting.

Then repeat the process for as many new intakes that you will have. I am using 4 - pumps, 3 - 1” intakes and my existing ¾” factory thru hull. I could have used the factory hull and just put another 1” intake and filled the screw holes but just didn’t want to mess with it. I decided to have three holes on one side and one on the other, due to space and the locations of the raw water intake, paddlewheel and depth finder mounted by the factory.

09-12-2011, 02:58 AM
Here are what the holes look like from the inside.



Now its time to install the new 1” thru-hulls. Have someone wait in the boat with a large (12”) crescent wrench to put the nut on the new intake and tighten it down, while you are under the boat. Put the 3M 4200 on the flange and put each one in and have your friend in the boat tighten the nut from the top. I put the 4200 on the intake flange and the nut flange just in case. Use your finger to wipe the extra 4200 from around the fitting like you would when caulking a bathtub. Take a rag with you to clean up the excess 4200 from your hands. Then let it dry for a few hours if its hot out or a day if its cold.

09-12-2011, 02:58 AM
Next up is drilling the extra vent hole for your IBS or fourth bag if you have one. If you are only doing three bags then you can skip this step. You will follow the steps almost the same as the ones under the boat.

To start get your drill and the 1 1/8” hole saw then measure the distance between any two existing drains thru-hulls you have on the boat so it will look symmetrical when your finished. If you don’t have two original drains next to each other then you can decide how close you want them to each other. My rear ones were really close together so I had to do the front ones the same so they will look right. The only difference with this one is that I did all my drilling from the outside so I could match the other one. Use your tape, center the fitting and measure twice. You will have a little leeway with the fitting since you can still move it about a ¼” in each direction once its in and before the 4200 dries. Yes I use the 4200 on all of my thru-hulls cause we have gotten water in the boat from those spots when weighted for surfing.




09-12-2011, 02:59 AM
Now I moved on to installing the Johnson pumps. There are many places to install your pumps and all of them have their advantages. I just chose to install mine in these places to make my life easier. It’s best to look around on the forums and see what others have done, then get in your boat with one of the pumps and try holding it up in a few places.

First I removed the carpeted panel under the rear seat cushion and above the bilge access to expose the fiberglass wall. If you don’t have this carpeted panel not to worry you won’t be able to see the screw holes anyway when the rear set is back in place.

Hold up the pump on the outside to mark your screw holes. I held the top of the motor flush with the bottom of the backrest off the seat. It is slightly toward the center to avoid being to close to my fuel intake lines.

09-12-2011, 03:00 AM
Drill the holes.


Mount the pump on the backside using the stainless steel screws, washers, lock washers and nylon lock nuts. It should hang low enough that you can access the hose connections and the impeller if necessary.

09-12-2011, 03:00 AM
Repeat the process for the second pump. If you are only doing three pumps you could mount them all here. If you are doing all four then only mount two here. I will plumb these two pumps to my ski locker sac and IBS.


09-12-2011, 03:01 AM
Next its time to mount the last two pumps to the engine side of the ski locker wall next to the back of the rear seat. As before hold the pump on the ski locker side to drill the holes. Mount them as high as you can without occluding the passage on the side for the fuel hoses etc.


Notice I used the stainless steel wing nuts on these since they will have to be removed to access the impellers if needed.

Repeat this process on the other side to mount the last pump. These pumps will fill/empty the v-drive locker sacs.

09-12-2011, 03:01 AM
Now you can start the plumbing process. Go ahead and mount the ball valves and insert the threaded hose barbs on each one. Then run the 1” ballast hose from each one to each pump. I used the factory ¾” thru-hull for my ski locker sac since it’s the smallest bag I have. Don’t worry about which side of the pump you rune the hose to. If its not the right side you just reverse the wiring on the switch and the pump will run the other way. Just run it to the most convenient side.


If you had the GIII originally you can just follow the mounting that they used from the factory. I started from where the sac is located with the 1” ballast hose in a big roll then run the hose back to the pump, that way I don’t cut the hose to long or to short. When putting the Quick Connects in the hose you will need a heat gun to soften the hose. The hose is 1” I.D. and the fittings are 1 1/8” O.D. makes it a fun process but a little heat goes a long way.

09-12-2011, 03:02 AM
No these two pumps are not plumbed together it just looks that way.





09-12-2011, 03:02 AM
Run your vent lines from the V-drive sacs to the opposite side of the boat. This will keep them from draining out the vent hose when you are on a sharp lean while surfing. (Starboard side bag vents to the Port side and vice versa.)


With the floor pulled out I route the new hose the same way the original was in the grove in the top of the gas tank.

Here it splits off and one goes to the ski locker and one goes under the helm and up and out to the bow sac. There is a tunnel in the ski locker that you can reach through to help pass the hose out of the hole under the helm that your wires and steering cables come out of. You practically have to lie in the ski locker with your feet in the bow to reach far enough to do this. Wear a long shirt or you will have an arm full of fiberglass. This is also the tunnel you can use to run a vent hose from the end of your ski locker bag as it is not vented from the factory. The vent will run to the old drain thru-hull for the ski locker bag.

09-12-2011, 03:03 AM
IBS connection and vent line. Yes I used ¾” hose and fittings for all my vents. I just reused the old tubing I had already ran. Be sure to order some plugs to plug the now empty holes in your bags


Be careful with the hose that goes to the ski locker it is a tight fit. If not when you put the floor back down it can cut the hose open.


Ski locker bag vent running into the tunnel under the helm. Then to the original drain for the ski locker as you will no longer need it.

09-12-2011, 03:03 AM
On to the electrical….. This is what the back of my GIII switchs and fuse block originally looked like before I unplugged them. I just did away with my GIII wiring harness and wired everything from scratch only using the GII fuse block.


I removed all the fuses and then unplugged all the connections for the “pump out” power wires, taped them up and tucked them away. You won’t need them any more.

Using the roll of red 16 gauge wire I bought I crimped on female terminals and hooked them to the “Pump Out” side of the fuse block marked them on each end and ran the three of them to were my GIII switches are located by the drivers seat. I just left the wires connected to the “solenoids” side and just never put the fuses back in that side.

09-12-2011, 03:04 AM
Next I ran four ground wires from the side of the breaker panel. Three to the original GIII switch panel. The other one goes to the unused ACC switch on the dash (you’ll see this pic later.)


I put female connectors on each wire of the power.

Due to the wiring of the pump to the switch you will need to have two connectors from each of the ground wires. So you’ll have 3 ground wires with double female clips on each end for a total of six female clips (Two grounds for each switch.)

09-12-2011, 03:05 AM
I then split up the double wire wakemakers sent me into four equal pieces, wired it to the pumps (White to Red and Black to Black) then ran it down the passage below the floor on the starboard side. Tape them together and run all four at one time as it is a pain. You will have to get into the ski locker again to feed these wires up through the hole below the helm then route three of them to the GIII switch plate and one to the ACC switch were you ran the ground wire earlier. Make sure to mark the ends with which pump they are connected to or you’ll be all mixed up trying to wire them.



From the end of each of these I then soldered two wires and clips to each individual wire as you will need two ends on each to make the pumps work both ways. If you look at the wiring diagram from wakemakers for reversible pumps to fill/drain switches it will make more sense.

On the other side of the Breaker panel from where you ran your ground you will need to run a power wire to the ACC switch on the dash (You will just disconnect everything from the back of the ACC switch and use the new power and ground you ran.). This is where you install the inline fuse. Make sure to take the fuse out first. I forgot to take the pic in the beginning so when I took it later I forgot to remove the fuse for the picture.

09-12-2011, 03:05 AM

Repeat the same soldering double ends to the pump wires and double the grounds as well for the dash switch. This switch will control the pump for my IBS bag.


Once you have wired everything like the diagram from wakemakers shows you can now put 20amp fuses into the fuse block on the “Pumps Out” side only. Leave the “Solenoids” side empty.

Now you are ready to test the switches and see if your wiring is good and the pumps works. If you are not doing this in the water only leave the pumps on for a few seconds each. Any longer can damage the impellers. Check that the pumps come on when the switch is on “fill” and “empty”. Also if you are not in the water the pumps will sound pretty loud until the hoses are filled with water. Don’t screw the switch panel back in yet. You want to leave it out until you are in the water to test the pumps for the direction of flow. Once you are in the water if the pump is doing the opposite of what the switch is set to then just pop off the front of the switch turn the body of the switch upside down and put the front back on. It should tell you this on the diagram if you ordered the fourth switch from wakemakers. I have not had a chance to test everything in the water and record the fill times so I will add that to the thread as soon as I can.

Well I think that’s it. Man these “How To” threads are pretty hard. My thanks goes out to all the people that do them on a regular or irregular basis. Hit me up if you have any questions, I may not be able to answer them but I can tell you who to talk to and what not to do for sure.

09-12-2011, 03:13 AM
I forgot to mention that all the photos were taken with my cell so please excuse the color/exposure on some of them. I just kept forgetting to take my camera with me and since my boat is in storage I have to do all the work on it at the storage building but I am only allowed to work on it outside on the street... I just love apartment living...

09-12-2011, 10:01 AM
Looks like a great "how to" thread!

Let me know if you want to come to Atlanta to do it again!?!?!

09-12-2011, 10:24 AM
Very impressive! I think that will be "the one project" I do this winter! Great how-to!

09-12-2011, 12:05 PM
Super clean install!! Just curious , how much do you have invested it the whole system?

09-12-2011, 12:51 PM
Super clean install!! Just curious , how much do you have invested it the whole system?

Do you want me to include the Tsunami pump upgrade I did first and then ripped out...HaHa! I really don't know at this point, I have been afraid to total it up. I got in on the group buy for the all the stuff for this install with the Johnson pumps, so I got a decent price on it. Lets just say it was still over a grand even with the discount. Then the cost of the two 1100's and the IBS I bought separate. The bad thing is I may not have enough projects to get me through the winter now. I will try to total everything up and send you a pm sometime this week.

09-12-2011, 12:53 PM
Looks like a great "how to" thread!

Let me know if you want to come to Atlanta to do it again!?!?!

We should all meet up in Vegas or somewhere and do a group install! Not sure if we would get much done in Vegas though.... Maybe Arkansas...

09-12-2011, 01:09 PM
I think we should do a Moomba owners national reunion every 4 or 5 years. I know I wouldn't miss it.

09-12-2011, 10:07 PM
Great install and how to! Let us know how you like it once u get a chance to test it. Just don't forget to shut off the pumps when emptying!

09-12-2011, 10:27 PM
Great install and how to! Let us know how you like it once u get a chance to test it. Just don't forget to shut off the pumps when emptying!

For sure I'll post the fill/empty times. I may have to get your help making a nice little chart like you did with the props.

I am sure I'll forget to turn them off at least once and burn the impellers up... Hopefully I will learn from that mistake when I make it.

09-12-2011, 11:55 PM
I think we should do a Moomba owners national reunion every 4 or 5 years. I know I wouldn't miss it.

Lake Powell? I've always wanted to go there. That'd be a good reason :)

09-20-2011, 07:55 PM
Great looking install. I like where you put the pumps. Very clean and great looking.

02-08-2012, 12:24 PM
Thank you for the great how-to! I'm also about to upgrade a 2008 LSV GIII to reversible pumps and your guide will be immensely helpful. Can you explain to me how the IBS bag is plumbed? Does the IBS drain through the reversible pump? Thanks again, Tom

03-05-2012, 04:04 PM
Not sure how I missed this thread when it was originally posted, but I just wanted to say great job on the install!

Based on your feedback (and that of others), we've actually put together a complete package that includes everything needed to upgrade a 2002-2008 factory Gravity III system to the 2009+ version. We're looking for someone to document their install as 08LSV did using the package, so if anyone is interested, get in touch with me and we'll try to work something out.


05-15-2012, 04:14 PM
Sorry for the late response I have been out of commission for a long time.... Long story.... Anyway I just ran the IBS line under the floor of the dash where the drain/vent lines were already running then out of the wall in front of your feet and to the IBS. Yes it drains from the same johnson pump that it fills from and vents from the new thru hull beside the one for the center bag that is now also a vent. Note you need to use a one way valve on the vent if you want it to suck the bag flat.