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Author Topic:   Additional Fuel Filter for Verado
BarryGreen posted 12-04-2005 07:45 PM ET (US)   Profile for BarryGreen   Send Email to BarryGreen  
I have always used a water separating Racor filter between any built-in fuel tank and the engines internal fuel filter. I have recently bought one to install in the spring on my 235 Conquest with 250 Verado, but seem to remember someone noting that this is not a good idea and that Mercury does not recommend an external filter with the Verado. Opinions, information?


handn posted 12-04-2005 08:14 PM ET (US)     Profile for handn  Send Email to handn     
I use external racor filters on my YamaMerc 225 efi 4-strokes with good results. The filters are rated 60 gph max and the engine may burn 30 gph max so any restriction on fuel flow is minimal.
I was told not to install external filters on my previous boat which had a 225 Optimax as the fuel pump on the Optimax was barely adequate for the job.
I don't know if this advice would apply to Verado engines. Hopefully Mercury has designed this engine with an adequate fuel pump.
The Mercury under cowl spin on filter does a good job as long as the filter element is changed during the 100 hour maintanence cycle. My Optimax without an external filter went 800 hours boating here in Mexico without a fuel related problem. I was careful where I fueled but the pump gas here is not as good as that in the U.S.
LHG posted 12-04-2005 08:23 PM ET (US)     Profile for LHG    
I would check with BW. If your boat did not come with one factory rigged, you don't need one. I do think I read somewhere that an external filter is specifically not recommended on the Verado. Too much restriction in the fuel flow, or something like that.

The YamaMerc 225 is a different animal, and not a Mercury product at all, except for a better soundproofing cowl design.

sosmerc posted 12-04-2005 08:24 PM ET (US)     Profile for sosmerc  Send Email to sosmerc     
Mercury is mostly concerned about possible fuel restriction due to external filters, fittings, and distribution hoses of improper size.
The Verado manual does not specifically state that you can't use a boat mounted filter, but they highly recommend that you use 3/8 in. inside diameter lines along with a "dedicated" fuel pickup for each engine (in the case of duals).
The engine mounted fuel filter system does provide a warning system for water in the fuel. The engine has both a low pressure 2 micron filter and a high pressure 20 micron filter.
If it were my boat, I would still want a Racor and locate it where I could easily open the tap on the bottom for easy and frequent check for debris and water. The engine mounted filter must first be depressurized (messy) and the filter element removed for inspection/replacement.
TRAFFICLAWYER posted 12-04-2005 08:32 PM ET (US)     Profile for TRAFFICLAWYER    
Most folks would agree 20 microns would let crap flow like a syph. Racors provide 10 microns.
sosmerc posted 12-04-2005 08:43 PM ET (US)     Profile for sosmerc  Send Email to sosmerc     
I just did some further reading of the 4 cylinder Verado manual and it says "do not install an accessory electric fuel pump or a FUEL LINE PRIMER BULB into the fuel system of this engine".
If you were to install a Racor between the engine and the fuel tank, how are you to "re-prime" it after you drain it for inspection? This could cause a problem. Maybe we really shouldn't need a boat mounted water seperator/fuel filter on Verado powered boats. (strange that the 6 cylinder Verado manual does not have this same warning in it. Maybe Merc learned something in the first year of the Verado and the newer 4 cylinder models are benefiting from the "experience").
BarryGreen posted 12-05-2005 08:07 AM ET (US)     Profile for BarryGreen  Send Email to BarryGreen     
Thanks for all the feedback. sosmerc: I agree, no matter what filters the engine provides internally I always like to ensure my tank is feeding it clean, water free fuel, so adding a Racor (or similar) filter should (IMHO) never create a problem. I also hate to have to wait until Smartcraft tells me I have water in the fuel, and then pull the cowling off at sea to drain it. A Racor allows me to inspect for water through the sight bowl periodically, and easily drain it through the bottom draincock.

As far as priming the system, I assume that while the post-fuel pump system under the engine cowl may stay pressurized, the pre-pump side does not. Otherwise, how would you start the engine on a new installation, if you run out of fuel, etc?

In my 235, the fuel line from the tank pickup to the engine runs across the face of a transverse panel under a convenient deck hatch near the stern, and it would be a natural to bolt a correctly sized Racor right there with no increase in hose length or need for right angle adapters.

I'll check on the Verado site and with Mercury and see if I can find anything definitive. My concern with Merc is that they will simply say "if we didn't provide, it you don't need it", an approach I don't necessarily agree with.

Since I believe that over time many of us here will have to deal with Verados on new Whalers, I'll report back whatever I find out. Thanks again, all!

sosmerc posted 12-10-2005 06:42 PM ET (US)     Profile for sosmerc  Send Email to sosmerc     
Hi BarryGreen !

Can you do me a favor? I don't have a Verado here to check for myself, or I would. I am trying to find out who makes the fuel injectors on the Verado. If it's not too difficult, could you look at your injectors and see if there are any names or numbers visible on the injector?
I belong to an Orbital Engine message board and a few members are trying to find out if these Verado injectors are supplied to Mercury thru our joint venture company named Synerject.
If you don't mind, please email me at if you find anything out!

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