Outboard fuel filter question

Vance in AK

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Ok, maybe a silly question...
I'm installing a canister type fuel filter/water separator on my boat with a 50hp Yamaha outboard. I use portable tanks. Do I want the filter in line before or after the priming bulb?
 

Tolman24

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Good question. I put mine before the bulbs on both the 115 main and the 9.9 kicker. Been using it 6 years. I do not know the correct answer.The issue that I could see is if your filter became restricted you bulb may collapse, similar to what happens if you do not have a vent on you tank. I would be interested in knowing what the correct answer is and if it matters.

My main tank go to one filter input and my portable tank can plug into the other input. Both have a shutoff valve. I then I have 2 output lines with a line going to the main and to the kicker, both have a shutoff valve and a priming bulb. Having the extra input line makes it easier to carry extra gas and not have to worry about trying to pour it into a tank when it is rocking and rolling.
 

Paul H

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I plumbed mine after the primer bulb, but I don't recall any particular reason. Like Ken I have both the main tank and a portable tank feed going to the filter with valves and just a single output as my kicker is a two stroke and runs pre-mix. The downside is I have two primer bulbs, but I guess that also gives me a backup.
 

.338WM

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The only difference I can see is the possibility of a piece of crud getting lodged in a check valve in the bulb and allowing backflow after engine shutdown. No big deal, that is what the bulb is there for. When I had my outboards, the filter was after the bulb and I never had an issue because of it.
 

MRFISH

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Wooldridge's factory install on my boat has the bulb between the filter and the motor.
 

Vance in AK

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Thanks guys.
Posted the same question on a Yamaha outboard forum. Combining the two forums there are 9 answers. 5 have the bulb between the tank & filter. 4 have the bulb between the filter & motor. None have ever had a problem related to their bulb location choice. Sounds like it's just a matter of which will be simpler to rig in my case. My father in law bought the boat new (20' Koffler Lite sled) in 87, & replaced the original 2 stroke with the new 4 stroke in 2004 (pretty low hours. Under 100 I believe. He was 82 when he put it on). He never installed an inline filter. Had some serious water related carb problems to deal with this season. I hope to use this boat on a moose hunt up north in a year or two.
Thanks for the input!
 

potbuilder

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I'd think with the bulb between the tank and filter you can use the bulb to prime the filter after a element change.
 

breausaw

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Here's a quagmire, I don't have a bulb on my fuel system. Perhaps it's because the Mercury Verado has two fuel pumps, sorry not much help.
 

pacific23

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Doesn't matter, before or after, the bubble will either PUSH fuel threw the filter or DRAW the fuel through it.
The bigger question is .....Do you have your primer bulb mounted correctly?
 

Anythingalaska

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Here's a quagmire, I don't have a bulb on my fuel system. Perhaps it's because the Mercury Verado has two fuel pumps, sorry not much help.

I don't have a bulb for my Verado either. You don't need one with those engines.

I have a bulb for my Yamaha 90 on my 15' whaler though; It's between the tank and filter. Honestly though it doesn't make any difference.
 

swampdonkey

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Mine is after the primer bulb. I squeeze it and I can see fuel swirl/movement in the bowl. Sediment or water (if present) is also seen when squeezing it or shortly after squeezing it.
Works great like that IMHO...
 

Vance in AK

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Doesn't matter, before or after, the bubble will either PUSH fuel threw the filter or DRAW the fuel through it.
The bigger question is .....Do you have your primer bulb mounted correctly?

Well it's done a good job for quite a few years....
 

mbarth

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I'd think with the bulb between the tank and filter you can use the bulb to prime the filter after a element change.

I agree. I have my primer bulb between the filter and the tank for this reason.

I'm not sure what type of filter setup you have, but I highly recommend the Raycor filters. I had a situation where I kept getting water in my fuel and could not find out where it was coming from. It would always happen at the worst time (rough seas) and the motor would cut off. A tech at Yamaha told me about the Raycor filters. They have a clear bowl on the bottom with a drain. Sure enough, the next time it was rough. I got water in the tank again and could verify that by looking at filter bowl. The Raycor stops the water from getting passed through to the motor. So, when the motor started cutting out, I just drained the water into a bottle and kept on going.

By the way, after a bunch of searching, I finally found that the water was getting into my tank through the fuel vent...

First thing I swapped out on the next boat was the fuel filter setup and the fuel tank vent. Since you're using portable tanks, this doesn't apply, but incase anyone's interested, I've been using the Attwood P-trap vent and haven't had any issues. Here's the link: http://www.attwoodmarine.com/store/product/90--P-Trap-Fuel-Tank-Vent
 

IceKing02

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Just finished Nigel Calder's "Marine Diesel Engines" wherein he does recommend that the bulb be used to fill the water separator/Primary fuel filter. So, prior to the fuel/water separator.
 

rosscoak

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it rains so hard here in southeast you will have water get in either thru the vent or via condensation in portable tanks....a heavy rubber vehicle floor mat laying over the tank helps that and keeps uv rays from rotting the plastic...the raycor
catches the "chud" and condensate water....water can and will lay in the low spot of the bulb....it only makes sense in my mind to place the primer bulb before the filter...just my .02

rossco
 
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