Hooking up an outboard full line help

1990 4.3 v6 - Bluewater 19’ Cuddy -

I got my 4 stroke kicker mounted with a new lift bracket the other day, and it already has a hole in the stern with a rubber grommet for the fuel line going to the motor.

But there are no accommodations for hooking the trolling motor fuel line to th main gas tank. I want to eleminate the carry on fuel tank. Can I simply put a tee in the fuel line between the electric fuel pump and the tank?


oooops! I spelled fuel wrong on the topic heading...

thanks, Kirk

install a fuel water sep ,it has 2 outlets. install 2 manual shutoffs in the housing, then the 2 fuel lines

Ok.... let me try this again....where do I tie into the main engine fuel line? Between the tank and the fuel pump?

i have no idea what you are talking about using a water separator with two outlets, two fuel lines, and two shut off valves.

are you talking about an in-line water separator/filter and use a shut off valve on either side? What is the purpose of these shut off valves? This makes no sense to me. Kirk

kirkll said:

Ok.... let me try this again....where do I tie into the main engine fuel line? Between the tank and the fuel pump?

i have no idea what you are talking about using a water separator with two outlets, two fuel lines, and two shut off valves.

are you talking about an in-line water separator/filter and use a shut off valve on either side? What is the purpose of these shut off valves? This makes no sense to me. Kirk

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Your Marine fuel filter base will typically offer two outlets and two inlets.
Run your kicker engine's fuel supply from one of the outlets.



*** In order to prevent the kicker engine from pulling on the main engine's fuel supply, you can add an Anti-Siphon valve at the outlet that will be providing fuel to the main engine.
While at it, you may as well install two of them... one for the main engine's fuel supply, and one for the kicker engine's fuel supply.

These are nothing more than a low spring pressure check valve.
One is required (USCG reg) to be installed right at the fuel tank's outlet fitting, just upstream from the fuel filter unit.

The purpose of them is to prevent a siphon in the event of a fuel line leak.

In your case, you would be using two of them as to prevent what I described above ***.



I see no reason for installing shut-off valves that would require you to open the engine bay hatch, and switch valving.
Two of these will take care of it automatically.





.

Thanks Rick.... Now i understand whats going on. Kirk

Ok... I was out putting in a new bilge pump and looked these fuel lines over closely. There is no water/fuel separator on this motor, or mounted remotely either. It’s set up with a new gas tank, the hose coming out of the tank , into a inline gas filter, then into an electric fuel pump that goes directly to the carburetor.

everything looks brand new and it works fine , all new hoses, and it works fine.... but is it safe?

There is no water/fuel separator on this motor, or mounted remotely either. It’s set up with a new gas tank, the hose coming out of the tank , into a inline gas filter,

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Ayuh,...... Get rid of the useless in-line filter, 'n put a water sep/ filter in it's place,....

Yes...... and mount the new Marine fuel filter upstream from the fuel pump!

into a inline gas filter,

Not legal

Looks like I’ve got some cheap generic electric auto fuel pump too. Aren’t those fuel pumps subject to coast guard inspection? Looks like I’m going to have to do the whole thing over again.... Kirk

kirkll said:

Looks like I’ve got some cheap generic electric auto fuel pump too. Aren’t those fuel pumps subject to coast guard inspection?
Yes, as well as the starter motor, ignition distributor, alternator, and/or any other electrical device that would be in the engine bay!

Looks like I’m going to have to do the whole thing over again.... Kirk

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Just to clarify:

The fuel filter (carbureted engines) must be installed in the suction side of the system...... not in the pressurized side!
In other words, it would be installed immediately after the fuel tank, and prior to the fuel pump!

You may get by with the little metal in-line filter on the suction side, but not on the pressurized side.
The little plastic see-thru filters are not legal in any event.

An Anti-Siphon valve must be installed in the fuel tank outlet fitting, of which would be prior to the fuel filter.
In your case, you will end up with 3 of these.
The light spring pressure check will not be accumulative. In other words, if 2 Hg is required to open one anti-siphon valve, that same 2 Hg will open both of them in line.


The gasoline electric fuel pump must be "ignition source protected" or "ignition source suppressed".

Example:


The electric fuel pump's circuit must have a means of cutting electrical power in the event of an engine stall.
This is typically accomplished with the use of a N/O Low Oil Pressure switch that is installed in the engine's oiling system.
We can rely on the N/O LOPS to supply power to the fuel pump, or, we can let the N/O LOPS trigger a relay that will power the fuel pump.

While not a requirement (but certainly necessary), we also need a means of powering the fuel pump prior to engine oil pressure coming up.
This can be accomplished by two means:
..... a start-by-pass circuit, typically triggered by the starter motor's S circuit.
..... a momentary helm switch (must be momentary).

What ever you do, you'll want to avoid any possible electric feed-back.
This is why I prefer using a relay in the loop.


.

For fuel line, I highly recommend Shields Flex-acol which is marine hose that is safe for ethanol added fuels. When you attach this hose, use good quality all-stainless hose clamps like AWAB that don't cut into the hose casing.
On a small runabout like yours this next recommendation may be considered overkill but: you might consider using a two pump system. Most modern boats already have this. It consists of a "lift" pump which pumps fuel to the water separating filter canister, and a second "engine" pump which pumps to the carb/injection. Your 1990 engine should still be designed with the mechanical pump accommodation still in place, and may be simply blocked off. Dunno. If there is no engine pump then you can add your (marine rated) electric fuel pump which has to be mounted on the engine. This should also have a filter between the pump and the fuel inlet. The Mercruiser solution was with something called a VST (vapor separation tank) which is a unit that mounts on the engine and combines a vapor lock reducing tank, a fuel pump and filter. It is something you might want to look into as an all-in-one addition to your redesigned fuel system.
The advantage of this is that there will always be sufficient pressure for both OB and main engine when the main is not in use.
Anyway, something to think about as you stir your coffee.

.........

o2batsea said:

For fuel line, I highly recommend Shields Flex-acol which is marine hose that is safe for ethanol added fuels. When you attach this hose, use good quality all-stainless hose clamps like AWAB that don't cut into the hose casing.
Excellent point. Those, or the Euro style band clamps.

On a small runabout like yours this next recommendation may be considered overkill but: you might consider using a two pump system. Most modern boats already have this. It consists of a "lift" pump which pumps fuel to the water separating filter canister,
I don't think that would be advisable!
A lift pump would pressurize a standard Marine carburetor style filter canister.

and a second "engine" pump which pumps to the carb/injection. Your 1990 engine should still be designed with the mechanical pump accommodation still in place, and may be simply blocked off. Dunno. If there is no engine pump then you can add your (marine rated) electric fuel pump which has to be mounted on the engine.
The approved electric fuel pump can also be mounted within XX" of the engine. This distance can be found within the USCG regs.

Click to expand...

An anti-syphon valve requirement is not a given but determined by the details of the installation of the tank and the engine into a given hull...blanket statements inferring they are ALWAYS required are NOT accurate.

Placing multiple anti-syphon valves in series is NOT a recommended practice.

.................

makomark said:

An anti-syphon valve requirement is not a given but determined by the details of the installation of the tank and the engine into a given hull...blanket statements inferring they are ALWAYS required are NOT accurate.
Mark, you may be correct.
I say: error on the side of safety.

Placing multiple anti-syphon valves in series is NOT a recommended practice.
All due respect, can you provide info that suggests this?

Like said earlier...... The light spring pressure check will not be accumulative. In other words, if 2 Hg is required to open one anti-siphon valve, that same 2 Hg will open both of them in line.

Click to expand...

Well this may take several cups of coffee to swallow, but maybe something stronger to digest completely later this afternoon. Conflicting recommendations have me a bit confused at first blush. Common sense tells me the fuel filter should be, and is at present just coming off the tank and the fuel is being drawn through it with the pump. Pumping unfiltered fuel into a filter doesn’t sound like a good plan to me.

I think I have the plumbing figured out with all this help, but the wiring is going to take more than a couple cups of Joe to comprehend. DC Electrical work has never been my strong suit. But.... I definitely don’t want to blow up, or have a nasty coast guard inspection. That wouldn’t be uncommon in my area to get checked out. No matter.... I want this thing safe.

kirk

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kirkll said:

Well this may take several cups of coffee to swallow, but maybe something stronger to digest completely later this afternoon. Conflicting recommendations have me a bit confused at first blush.

Common sense tells me the fuel filter should be, and is at presently just coming off the tank and the fuel is being drawn through it with the pump.
Correct!
And that would be both the fuel filter cartridge and the Anti-Siphon valve.... if equipped.

Pumping unfiltered fuel into a filter doesn’t sound like a good plan to me.
It's not that.
It's that this style fuel filter is not designed to be pressurized, even if only 4 to 7 psi!

I think I have the plumbing figured out with all this help, but the wiring is going to take more than a couple cups of Joe to comprehend. DC Electrical work has never been my strong suit. But.... I definitely don’t want to blow up, or have a nasty coast guard inspection. That wouldn’t be uncommon in my area to get checked out. No matter.... I want this thing safe.

Very simple:

First off...... I would NOT power the fuel pump with the ignition circuit. The distance from the helm to the engine, the hull harness/engine harness connector, etc , all add resistance to this rather light gauge circuit.

Which ever method you chose, the circuit must be interrupted by the N/O low oil pressure switch in the absence of oil pressure.

The start-by-pass circuit is a bit more involved.
When you get to that point, post back.

kirk

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RicardoMarine said:

..........Placing multiple anti-syphon valves in series is NOT a recommended practice.
All due respect, can you provide info that suggests this?

Like said earlier...... The light spring pressure check will not be accumulative. In other words, if 2 Hg is required to open one anti-siphon valve, that same 2 Hg will open both of them in line........

Click to expand...

The fuel delivery system should be configured to minimize restrictions and pressure drops while complying with the CFR, especially given the product sold as "gasoline" nowadays...

Nobody suggested the the cracking pressures of any A/S valves would be cumulative; that said, their restrictions would be. And to go further, try to find some published figures on A/S valves citing those values let alone any tolerance. Probably no BFD on a 'luggable' kicker but not a good choice on a V-8, especially if the fuel line used is marginal in cross section. If there is any doubt remaining, look at the current installation requirements, from any OEM, on what the max pressure drop on the fuel inlet plumbing is...

makomark said:

Nobody suggested the the cracking pressures of any A/S valves would be cumulative;

Mark, I was referring to the idea that vacuum against two A/S valves (in series) would not be accumulative.
Accumulative, as in if one required 2 hg to pull the check ball from it's seat, two of them (in series) would not necessarily require 4 hg to pull the check balls from their seats!

that said, their restrictions would be.
Yes, I would agree with you on that!

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In other words, if the auxiliary engine is being used, ASV "B" would be in check, whereas ASVs "A" and "C" would both crack open.
Yes/no????

This is just me, but I have a huge issue running the kicker from the main engine supply. Is it really such a big thing to have the extra tank on board?

o2batsea said:

This is just me, but I have a huge issue running the kicker from the main engine supply. Is it really such a big thing to have the extra tank on board?

Click to expand...

I'm beginning to think you may have a good point here brutha.... i was originally thinking this was not going to be a big deal to do, and wouldn't have to deal with tripping over the extra tank.

Now i'm thinking i may just build a box around the portable tank and use it as a step, and forget about all this nonsense...... Looks like i do need to get a different fuel pump that is legal to run, and probably should put the water /fuel seperator filter in. So all this has not been a wasted query. I sure appreciate the feed back from all of you. Kirk