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New Caddy boat questions

John C

John C

Well-known member
I picked up my new hull from Hamant and dropped it off at c chardts place so he can start on the metal works. It's a 15x8, side by side front operator and triple rear. Chris is going to build it with 3/4in square tube. any suggestions or changes I should be aware of before I start the build? I plan on moving the radiator a little farther foward than my last one to allow for better air flow in front of the prop. I am planning on two sets of jacks. I have heard that some of the bigger boats have three jacks. Is there an advantage to a third jack on a 15ft boat? What kind of fuel pump are most of the Caddy guys running.? I was running the stock mechanical pump with a nappa electric fuel pump inline between the fuel filter and the motor.
 
i was told that the stock fuel pump will support 500 hp with out fuel pressure demand problems,but if you need alittle more robmc pumps are nice but just alittle costly.they are mechanical.
 
gh I am sure that chris will be posting some pictures soon. He is going to start on the engine stand tomorrow. The hull turned out real nice. I had it built 4in wider than the standard 8ft boat, kinda like the wide trax. And she has 4 extra T Bars to stiffen up the bottom.
Bondsman, I have never heard of robmc fuel pump. Where can I get some info.
 
bondsman":d6tmxxli said:
i was told that the stock fuel pump will support 500 hp with out fuel pressure demand problems,but if you need alittle more robmc pumps are nice but just alittle costly.they are mechanical.
Click to expand...

Well if that's right then I've got more than 500hp. I was running a stock pump with a NAPA elc pump and anything over 4000rmp it would start starving for fuel. I went with a Holley Blue elc. pump and I run a steady 7psi all the time. Are you running DD or a gearbox?
 
a1mudpuppy, its a gearbox boat. I talked to you on the 3a run at the tower. I had the green fiberglass boat that was for sale. I sold the boat, wanted to go to a alum. hull with poly. kept the engine, its a 520 caddy making a little over 500 HP. sold the 2.37:1 and went to a 2.68:1. Just want to try to get everything right when putting the new one together. Is anyone running a carter or malory electric fuel pump?
 
mudpuppy , when you went to the holly blue elc. pump did you do away with the mechanical pump? Or just replace the nappa elc. with the holly blue elc. and keep the stock mechanical pump.
 
Only use the Holley pump and keep the NAPA for a back up.

Bondsman, you maybe right, I didn't put the fuel pressure gauge on until I was using the Holley
 
Holley blue is the way to go. I had to get one for my boat because it kept starving of fuel, tried two other before going to the blue.
 
mudpuppy, does your holly blue elc. pump stright to the carb? or does it pump to the mechanical pump and then to the carb?
 
Never had anything but problems with Holley pumps. I have run a Mallory 60fi, with a regulator and a return for years---they are great pumps and rebuildable. Charles
 
Ruagatr, someone else also recommended that I use a Mallory fuel pump. He said that I should try the Pro Comp 140. My question is do you run the fuel line straight to the carb after the electric pump and bypass the mech. stock pump. Or do you run the fuel line from the electric pump to the mech. pump then to the carb?
 
As Fatboy540 said---throw away the mechanical pump and run direct with a regulator. I prefer the mallory regulators too. If I was forced to run a Holley, it would be the "Black" pump. The red pump is truly useless, I have no personal experience with the blue pump. But a websearch will help you on this topic. Regards, Charles
 
you can get six piston mech fuel pump from Potter at Cadillac Performance. This is a custom made fuel pump and it can feed your elephant all the peanuts it needs.
 
Thanks for all the fuel pump info. Any thoughts on jacks? I was planning on two, the hull is a 15x8. I have heard that some of the bigger boats have 3. Maybe Ruagatr or some of you guys with the bigger boats will chime in here and let me know how your boats are set up. Pros and cons of multiple jacks. My last boat didn't have any jacks so I am not real familiar with them.
 
I have two jacks but if I need another I will install it. On my boat I have a jack at 20" from the transom and another jack at 52" from the transom. The back of your boat takes the lions share of teh abuse so it is where you need the jacks.
 
John C let CC build the boat he one of the best on gettin the giggin set just right. The man is good.


I run a DD Caddy with A elc. pump to the mech. to the carb.
 
JOHN ! READ THE SPECS ON THE PUMPS SOME PUMPS DONT HAVE THE FLOW RATE AS A STOCK ONE ! ITS A MARKETING DEAL ! THEY ARE MEASURED BY FREE FLOW !THAT MEANS NO RESTRICTION ! LIKE SHOOTING INTO THE AIR NOT HOOK UP ! WHEN YOU HOOK THEM UP FREE FLOW MEANS NOTHING ! JUST GET ONE AND BUY A REGULATOR ! MALLORY OR BARRY GRANT !IS MY CHOICE BUT NOT WALLETT FRIENDLY! I AGREE WITH CLARLES ABOUT THE BLUE AND THE RED NOT FOR THE CAD !
 
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