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Flo scan - filter recommendation

bobct

Advanced Contributor
I just ordered Flo scans (twinscan) unit. I have carb'd 454's with mechanical fuel pumps. I'm running the original in line canister filters before the pump and have the small screens at the carbs. No fuel issues thus far, I check and change the filters regularly.

Flo scan is recommending a 30 micron filter be installed before the sending units. Not as a filter per se, but just to keep the senders clean. I didn't really want to mess around with the hard/metal line which goes out of the filter and to the pump.

I have flexible hose coming from my bypass valve going to the inlet on the filter. This is where I was thinking of installing the add'l filter and sending units. With this setup, I won't need the dampening valve because the senders will be before the main filter.

Do you guys have any recommendations? I suppose this would be the opportunity to bypass the original canister filters and install Racors but I don't know if 30 microns is too large if I eliminate my other filter. I don't know how many microns the existing filter is.

I can't seem to find a simple, in-line 30 micron filter though which was my original thought.


Bob
 
I"ve been using Racor S3220UL a couple feet before the fuel sensor. No other filters in the system necessary. But, the dampening "bomb" was helpful.
 
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I"ve been using Racor S3220UL a couple feet before the fuel sensor. No other filters in the system necessary. But, the dampening "bomb" was helpful.
Dave has this correct, and you can't beat the RACOR system! The RACOR can be retro-fit to most any fuel filter base as long as you have space for the bottom metal bowl.
Bob, this has come up many times on the BOC forum, and each and every time the little in-line filter topic comes up.
I understand that the manufacturer wants a 30 micron filter up-stream of their unit..... and for good reason.
Not that you have suggested this, but the little in-line filters should NEVER become a primary and there is no need for a secondary, IMO!

IMO, you'd be ahead of the game to take your existing fuel filters off-engine and remotely mount them so that your flow sensors can be installed after them.
These will still serve as your primary, and there will be no need for any other filtration.
If you use a 30 micron filter, you have satisfied the manufactuer's requirements.
 
Bob:

Mine is set up similar to Diver Dave's. The OEM cannister filter was removed decades ago (I had issues getting both sides to stop leaking). The hosess run forward from the tank, thru the sutoff valves, and into a Mercruiser Filter head with RACOR elements - no separate metal bowl versions. From there the hoses go to the FloScan paddlewheels, and into the pump. Original styled hardline from there up to the carb.

Not optimal but has worked very well since the original "mod".
 
On a Merc 454 (I'm currently replacing it with a Crusader after many-many hours of service), I had the Merc factory spin on filter. Since it was a Gen VI, there was a return line that Merc went back to the filter assembly. That made putting it after the filter a problem. For other reasons, I did not want an extra filter in line and was reluctant to fiddle with the factory's setup. Anyhow, with the expectation of screwing up the flowscan sensor, I put it on ahead of the filter. That was a few thousand hours of operation ago. The whole deal has worked great. The flowscan sensor does not seem to stop anything small and continues to work fine.

The other answers here that place a filter in front of the sensor are better if they will work for you. I needed to do otherwise and both the sensor and I have survived it.

Bruce Clarkson
 
Thanks guys, are you using 10 micron filters? I guess I could just eliminate the old canisters all together, use 10 as my primary and leave the carb screen intact.

I wasn't sure if the 10 micron might cause too much restriction before the sender which is why Floscan recommened 30. I called them back and got a "it should be ok" sort of answer.

Bob
 
the 5510's I have are 10 micron.

Racor offers other "options" but you have to go to an element with the metal bowl on the bottom. You don't need the 2 micron version and I can't remember what the larger rating is.
 
got it, I just ordered two 10 Micron Racor assemblies. So, it should look something like this when I'm done:



Tank---->crossover----->racor---->sending unit---->old filter connection---->
fuel pump--->carb filter----->empty wallet

Short term, can I just remove the canister filters and leave the canisters in place? They're brand new so no issues with integrity. I guess I can just get a union, just not sure if I have enough "slack" on one or both ends to make the connection, plus that's what my coil mounts to.
 
I don't see any reason why not...just make sure it is leak free when reassembled.

As far as the union goes, you may need an extra pair and a couple short nipples. that will let you 'stretch' the union to minimize the 'slack' needed in the existing hardware.
 
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