Priming bulb before or after filter? - Page 2

doggypaddle · 22 January 2009, 11:03

well i would do neither

I would put one primer bulb before the filter. and after the changeover valves. and keep the pipework from the tanks as low and short as possible and keep the filter and primer bulb below the level of the top of the fuel tank.
Three primer bulbs would work of course but its a bit unnessecary.
what i would not do is put the primer bulb after any filter other than the strainer in the tank, or at a height where its much higher than the top of the tank. its asking for an airlock thats a bugger to shift.

doggypaddle · 22 January 2009, 11:12

The more i think about it the more obvious it becomes

pre made fuel hoses have 6" hose on the suck side and 2feet on the pressure side,
All motor vehicles have (excepting agglomerators and coarse strainers) filters after pumps not before, and fuel pumps as low down as possible, usually in the tank.

EDIT
i looked as some hoses i have and some have long suck lines and short pressure lines!
looking on the net though general recomendation is primers mounted vertically arrow up, downstream of filters and near tank height.

Downhilldai · 22 January 2009, 11:38

I agree with Dirk...............and that's what it says in the manual too.

doggypaddle · 22 January 2009, 11:51

In reality if the filter is just a water trap it makes bugger all difference if its before or after the bulb, my SR was Rigged by the admiralty shipyard and they put the filter AFTER the bulb on the transom low down,

An old mercury manual i have shows the filter AFTER the bulb too. You have a manual that shows it before

I still maintain that in an emergengy with a partly blocked filter you can force fuel through it with the primer bulb to get you out of trouble if its before the filter,
conversley you can use the bulb as an indicator of a blockage if its the other way around it will start to collapse on WOT before it causes a problem..........

RACOR SAY....."The primer bulb can be on either side of the filter, but before the filter makes it easier to fill and prime."

Downhilldai · 22 January 2009, 12:15

Quote:

Originally Posted by doggypaddle

..RACOR SAY....."The primer bulb can be on either side of the filter, but before the filter makes it easier to fill and prime."

That's interesting, 'cos it was the RACOR manual which stipulated the bulb should be after the filter

biffer · 22 January 2009, 12:34

thankyou downhilldai, separ filters the same, we could argue till the cows come home, but i'm not going to, got a picture somewhere of two of these bulbs stuck on my tits, hows that done if they dont create vacuum

jwalker · 22 January 2009, 12:37

Quote:

Originally Posted by biffer

...got a picture somewhere of two of these bulbs stuck on my tits,...

To much information.

doggypaddle · 22 January 2009, 12:37

[quote=Downhilldai;279414] That's interesting, 'cos it was the RACOR manual which stipulated the bulb should be after the filter

[/quote

RACOR cant make up their mind either, or the website i got that info from is wrong, but it can't be it was on T'internet so it must be right

heres the definitive answer......

"Install the filter somewhere in the fuel line with the flow in the direction of the arrow"

biffer · 22 January 2009, 12:39

same as that

jwalker · 22 January 2009, 12:39

I refer you back to first sentence, post number 2.

doggypaddle · 22 January 2009, 12:43

Quote:

Originally Posted by biffer

thankyou downhilldai, separ filters the same, we could argue till the cows come home, but i'm not going to, got a picture somewhere of two of these bulbs stuck on my tits, hows that done if they dont create vacuum

Of course they create a partial vacuum, i never said they didn't, what i meant was they will push fuel higher than they will suck it!

Go on post a picture of your nipple suckers in situ

biffer · 22 January 2009, 12:44

do you think we took the record for the best view per posts ratio

doggypaddle · 22 January 2009, 12:53

Quote:

Originally Posted by biffer

do you think we took the record for the best view per posts ratio

probably!

Heres another spanner in the works to think about though.......i had a look on the separ website and there is a nice cross section of a filter showing a bleed screw at the top.
see my point? if the bleed screw it to get air out, then the primer has to be before the filter

or you will be pumping all day(ooh err) and sucking air in

I give up! either way works

Downhilldai · 22 January 2009, 13:17

Quote:

Originally Posted by biffer

do you think we took the record for the best view per posts ratio

No, we're way behind JSP's 'changing gear oil' thread:

http://rib.net/forum/showthread.php?t=27971

biffer · 22 January 2009, 14:24

the 10mm nut on the separ is more for back flushing the filter, open the tap on the bottom and release the nut on the top and it pulls all the crap off the filter into the bowl, back flushing works quite well, imo only recor or separ are worth fitting

AVONMON · 23 January 2009, 10:34

The priming bulb should be after the filter.Fitted in the vertical plane before the engine.If fitted before the filter there is the potential to burst the filter element medium and allow unfiltered fuel to the engine.The priming bulb would be operating in unfiltered fuel and the non return valve subject to debris contamination and hence loss of priming efficiency.Use O.E.M primer for your particular engine and S/S crimped pipe fittings,steer clear of jubilee and plastic ratchet type pipe fittings.Only M.H.O !

JSP · 23 January 2009, 14:31

Is anything about an outboard set up simple except for the tucker using it?

Will leave it as it is. Mines after a water separating fuel filter, that make any difference?

Dirk Diggler · 23 January 2009, 18:15

Quote:

Originally Posted by JSP

Is anything about an outboard set up simple except for the tucker using it?

Yeh, there's the right way and the wrong way! And it seems the majority are yet again wrong!

doggypaddle · 23 January 2009, 18:22

Quote:

Originally Posted by Dirk Diggler

Yeh, there's the right way and the wrong way! And it seems the majority are yet again wrong!

Do you include the OEM in that statement who fit filters in the powerhead after the primer

Once again my mate who works for a filter manufacturer has clarified things,
aparently a water separator can go before or after a primer,but the primer should always be close to the tank , a micronic filter should go AFTER the primer and after the fuel lift pump due to the more restrictive nature of the filter medium.

Dirk Diggler · 23 January 2009, 18:32

Who really cares. It isn't really going to make much difference where it is. And it only really matters if you have inbuilt tanks. A portable 20 litre or so tank doesn't really need a filter, hence the reason why the motor comes with a fuel tank and fuel line that doesn't have provision for a filter.

I only fit spin on water seperators to outboards (60+ hp) as per the manufacturers instructions. And then only if the boat has integral tanks. At one time we were informed by Barrus not to fit anything to OPTI's, as they had their own filter on the powerhead, this has now been revised to a mercury style spin on and a bulkhead fitting.

When asked by the customer for something in excess of that, I fit a Racor, as they seem to be the only ones that are approved for petrol, most of the separ type filters seem to be for derv only.