External Fuel Filter, why?

[Capt.Will]

I bought this 19' Mako last year from Louisiana and use it now only in Michigan fresh water. It came with an external fuel filter that appears to have been installed/mounted by the previous owner.

Questions I have are....Is it necessary? Why would someone install this when the engine has a fuel/water separator already on the engine?

I friend of mine told me that it is a "saltwater thing". Many saltwater fisherman install them but really do not know why.

I would prefer to eliminate it so to not have the excess hose and component on the transom, but if there are more reasons to have it then I will deal with it.

Your thoughts!

 

[hughespat57]

If your sure the on engine is a water separator it's likely just a matter of convenience. The external could be swapped easily while underway without the need to risk losing the cowling or falling overboard. Fits the "it's a saltwater thing". Depends how far offshore you're willing to change the under cowl filter.

 

[b_arrington]

Provides large capacity yet easily changed filtration and water separation. It's likely more easily accessed and changed vs. the engine filter. Also provides additional filtration over just the engine. If you get the filter clogged, the one downstream is probably still fine; just spin on a new element. I'd leave it.

 

[Capt.Will]

If your sure the on engine is a water separator it's likely just a matter of convenience. The external could be swapped easily while underway without the need to risk losing the cowling or falling overboard. Fits the "it's a saltwater thing". Depends how far offshore you're willing to change the under cowl filter.

That is an interesting point on the saltwater thing.

I changed the onboard fuel filter when I first bought the boat and I confirm that it is a fuel water separator. The engine has a wire connection on the bottom to sense any water in the fuel.

 

[KevinC]

On outboards many times they will also install one with a "site glass" on the bottom of the filter (filter has threads on both top an bottom). This way you can see if there is water being separated out and even drain the water. Inboards generally have the solid filter like the one pictured as I do not believe the plastic site glass meets fire standards.

-Kevin

 

[Capt.Will]

On outboards many times they will also install one with a "site glass" on the bottom of the filter (filter has threads on both top an bottom). This way you can see if there is water being separated out and even drain the water. Inboards generally have the solid filter like the one pictured as I do not believe the plastic site glass meets fire standards.

-Kevin

Originally it came with the plastic site on the bottom. It seemed very old and all I could find locally for a replacement was the one you see in the photo. Honestly, it's a bit more aesthetically pleasing this way if I decide to keep it.

 

[Blueone]

Keep it…. How can more filtration be bad?….

 

[KevinC]

Originally it came with the plastic site on the bottom. It seemed very old and all I could find locally for a replacement was the one you see in the photo. Honestly, it's a bit more aesthetically pleasing this way if I decide to keep it.

I would keep it - these on board tanks are exposed to much more humidity and will separate the water out preventing problems. The inline filter is only design to remove dirt that has found its way into the tank. On my Pro-Line center console I use the solid filter - it does not hurt it - just remember to fill the new filter with gas when changing out.

If you ever want the site glass in the future you can always add that back - just find a new bottom and appropriate filter - should be easy to find online and it makes it easy to see if there is water is the fuel. Otherwise you need to pull the whole filter an dump it into a jar and to see if water separates out.

-Kevin

 

[hughespat57]

That is an interesting point on the saltwater thing.

I changed the onboard fuel filter when I first bought the boat and I confirm that it is a fuel water separator. The engine has a wire connection on the bottom to sense any water in the fuel.

The water sensor is great however if that sensor shuts the engine down when water is detected, you have to change the filter no matter where you happen to be. I would hope it's just an alarm.

Even then how long would you want to risk running with the alarm/light before being able to change it?

I would find a new sight bowl and keep it as it was.

 

[bahamabreisus]

Sight bowl ones are made by Racor. They have a drain on the bottom. Racors will be at least twice the price.

 

[b_arrington]

Sight bowl ones are made by Racor. They have a drain on the bottom. Racors will be at least twice the price.

They make the spin on types too, like this one. They are not nearly as expensive as a turbine. Replacement filters are similar to others - like $20-$30.

 

[bahamabreisus]

They make the spin on types too, like this one. They are not nearly as expensive as a turbine. Replacement filters are similar to others - like $20-$30.

View attachment 120744

That's the one I am talking about, Parker is Racor. The filter is $25-30 and the bottom sight glass piece is separate. They can run as much as $40 for it. Of course yo only replace canister each time.

 

[Stee6043]

I vote leave it. I've got two fuel filters per engine on my rig. So why not you?

 

[sbw1]

Tiara starting adding a third spin on high flow fuel filter to their new boats when marinas began selling e10 fuels. Ethanol cleans fuel lines as most of you know. That translates into more crude flowing through the fuel system. I am fan of clean fuel and would leave it in place.

 

[mrsrobinson]

When I wanted to add an extra filter I was informed not to because it can reduce the fuel pressure.

 

[KevinC]

When I wanted to add an extra filter I was informed not to because it can reduce the fuel pressure.

That will depend if the filter is properly rated for the fuel flow needs. Makes sense because if you need up to 30-GPH and only put in a filter that will restrict you to 20-GPH then the pump may be starved for fuel.

-Kevin

 

[scoflaw]

My OX66 outboard has 5 filters by design, leave it.

 

[sbw1]

When I wanted to add an extra filter I was informed not to because it can reduce the fuel pressure.

Tiara used high flow filters as the first line of defense right off the tanks. They mounted them high so they could be easily changed in rough seas with plenty of room for a bucket to catch any spills. The high flow addresses the fuel pressure issue. I’ll see if I can locate a picture.

 

[sbw1]

This is the third fuel filter showing just the port side filter. The other is hidden by the starboard riser. Both are accessible thru the day hatch which is to the right of light.

 

[scoflaw]

OP has an outboard