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Floscan Installation Contbd Fuel Lines

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brian_from_boston

Contributing Member
"I am going to try to install

"I am going to try to install the floscans in the next week. To remind you all this is a 1988 29' Blackfin Flybridge with twin inboard crusader 454's. I was forming a plan of attack today and followed the fuel line from the tank valves/oil filter style fuel filter. It is approximately 3/4" rubber line with hose clamps. I followed it on the port motor and near the right rear of the motor it ends at what looks like a diaphram with a V8 or pineapple juice can attached to the bottom. From here it procedes to the fuel pump by metal lines.

What is this diaghram like object? I am guessing it is a filter.

When securing the floscan, should I fasten it to a stringer or can I bolt it to an open bracket on the rear of the motor?

Any problems with having the floscan much lower than the fuel pump as in 1-2 feet?

As the lines exist now, the valves and 1st filter are fastened to the port wall at approximately the height of the carb. The lines then procede downward with no valleys to the pump. If I fasten to the stringer, it will go down below the motor and then rise back up to go through what I believe is the second filter.

Will this put too much strain on the pump?"
 
"From your description, there

"From your description, there appears to be a lot of 'stuff' before the fuel pump, and that's not good. (It can cause a fuel pressure loss at speed, which can lean out the mixture and burn pistons.) Lots of people get away with that for years--until they buy a load of cruddy fuel. This plugs the filters, starves the fuel pump, and leans out the motor.

Note: Filters should be located AFTER the pump, with only coarse strainer/ water separators before it.

Lecture over. Air is the enemy of a FloScan, so you want the flowmeter located low as possible, so the air will rise up and out of it. Also, you need it way before the fuel pump (it has minimal restriction) to reduce pulsation effect that screws up the readings. Finally, you have to make absolutely sure that no air gets pulled into the system before the flowmeter. In my case, the shut off valve--that never leaked a drop of gas--was allowing air to enter! Drove me (and the flowmeter) nuts. Had to relocate the flowmeter WAY back near the fuel tank--and before any valves--to keep the air out.

You wouldn't think a valve would allow that, but...

Jeff"
 
"Thanks Jeff,
I have on

"Thanks Jeff,
I have one main and 2 saddle tanks so this might be why its so busy before the pump. I picked up the new fuel lines today and will be installing over the next few days. Your making me nervous about leaning out. A good analogy I heard was leaning out a motor is like adding oxygen with an acetelyne cutting torch. Not good for the pistons. If everything is the way it was on build day, should I be removing any of the factory installs before the pump?

I'll let you know if it all works out. Thanks."
 
"Brain:

Like I said, I'

"Brain:

Like I said, I've seen a lot of boats set up that way--Merc outboards included--and they seem to get away with it until... Better to be safe than sorry, especially with that damn ethanol crap in our gas. (It stirs up crud that was happy lying on the bottom of the tank.)

Good luck!

Jeff"
 
"Installation complete Jeff!

"Installation complete Jeff! I am getting a reading of 2 gal/hour for each of the 454's at idle (600-700 RPM on the tach). Does this sound about right?

Jeff,
Would you recommend that I loop out the filter(what I believe is a filter, back of the motor looks like a V8 or pineapple juice can) before the pump and install an inline filter between the pump and the carb?

If so what would you put in for a filter between the pump and carb?"
 
"Two GPH at idle sounds about

"Two GPH at idle sounds about right--high ain't it!

The "pineapple can" could be a water separator/ strainer. If so, that's fine.

I use a NAPA in-line METAL can filter between the pump and carb. They sell various sizes (1/4 and 5/16 line size) so measure before you buy. A tubing cutter is all you need to install them, but be sure to use only MARINE rubber hose, and double clamp the non-filter sides. (The filter is too narrow for double clamps.)

Jeff"
 
"Brian I have the same engines

"Brian I have the same engines same year. My setup is tank to Racor to Floscan guage to small engine mouned filter. The "can" is another filter, no reason to remove it especially with E-10. Unscrew the can and there is small filter element inside. Should be able to get a new filter at most marine supply places or napa. Also make sure you get the rubber O ring that seals the can. Guesing hasnt been replaced ina while!

I get the sme about 1.5-2 gph at idle. Love to hear wht your numbers are at cruising speeds, rpm, gph, etc. Im running a 31' Tiara and getting about 12-13 gph per engine at 3050 rpm and 23 kts.

here are the part #s for the lttle filter from diff manufacturers, i use the napa about $3.00

Napa 3271
Crusader 91606
Sierra 187862 (i think)"
 
"Jeff,
What kind of maint

"Jeff,
What kind of maintainance do I need to perform on the pineapple F/W separator. Is there an internal filter than needs to be changed. They look a bit weathered as if it is an internal filter and the metal is a canister or holder.

Yeah, 2 GPH per motor is a kick in the teeth at idle. So double clamp the hose at the carb and the pump and singles at the filter. I will replace the fuel hoses they look like possible original.

Ok I replaced most of the fuel hose with the A-1 3/8" when installing the flowscans sensors. So for piece of mind I will replace all the hoses from the tank selectors forward. I will only use marine grade hose, however does anyone ever check that you are double clamped and what hose you used?"
 
"If that's a water separat

"If that's a water separator, you both need to change the element and put an extra or two on board.

If you get a USCG courtesy inspection, the single clamps won't pass. You can argue on the filter side, however, since there's not enough room for two.

Jeff"
 
Thanks Jeff and RM. I will re

Thanks Jeff and RM. I will replace the elements. RM do you have a filter between the pump and Carb? I will be taken the boat out hopefully soon and will post in here what I am burning at different RPM's and Speeds.

P.S. I double clamped all my fuel lines when I changed them I was just wondering if it's one of those things that you should do but no one will ever check.
 
"RM 2300 RPM's 12 knots 8

"RM 2300 RPM's 12 knots 8 GPH on Starboard and 9/10 on Port. Any idea why I have a 2 GPH difference between Port and Starboard? They are a matched set of floscan sensors. Another thing I noticed is when you accelerate the GPH spikes and then settles as in the 8 GPH on Starboard at 2300 RPM, it actually goes to 12 when I first accelerate then drops down to 8."
 
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