Installing fuel flow indicators-gctid394756

[Guest]

Here is a question on the legality of how fuel flow transmitters are installed.

It is my understanding that the fuel line to the carb has to be solid yet to install fuel flow transmitters it is necessary to cut this line and install the transmitters with rubber tubing and clamps.

They have to be after the fuel filter to insure clean fuel as anything in the fuel would be bad for the little turbines.

[Guest]

check737 wrote:
Here is a question on the legality of how fuel flow transmitters are installed.

It is my understanding that the fuel line to the carb has to be solid yet to install fuel flow transmitters it is necessary to cut this line and install the transmitters with rubber tubing and clamps.

They have to be after the fuel filter to insure clean fuel as anything in the fuel would be bad for the little turbines.

I installed an https://"http://www.amazon.com/Sierr...itional filter in the soft line and then put the flow meters between them and the engine-mounted filters with the hard line.

Cutting the hard line IMO is not a good option.

[Guest]

You cannot put the meters after the pump. You need to go between the thank and the pump. Therefore on most boats you need to install an additional filter before the meter. I used basic automotive 30 micron METAL BODY filters for this. They must be all-metal, no sight glass, plastic, etc.

[2850Bounty]

check737 wrote:
It is my understanding that the fuel line to the carb has to be solid yet to install fuel flow transmitters it is necessary to cut this line and install the transmitters with rubber tubing and clamps.

As per Carlos, the flow sensor installs between the main filter and the fuel pump.... not after the pump.

After the pump would be on the pressure side of the system!

There is no need for one of these in-line filters... metal or not!

The filter media square area is very small, and is subject to becoming restricted very easily.



Your main filter will work just fine.

.

[JimMc]

I have had fuel flow meters on two boats. On our current boat I have spin on filters in place before the fuel flow meters.

Fuel Flow on our boat.

Fuel Tank > Spin on filter (Pictured) > Fuel Flow Meter > Orginal on engine Spin on filter > Pump > Hard Line > Carb

[boatworkfl]

If installing Floscan meters you can download the instructions, better yet just call them and they will help.

[Guest]

There is no need for one of these in-line filters... metal or not!

The filter media square area is very small, and is subject to becoming restricted very easily.

Your main filter will work just fine.

Not according to the flow meter manufacturers. They all say you need a filter before the meter. I decided to try these simple filters this time, while in the past I've added the standard Sierra marine filters. So far I'm about 500 gallons into it, and they show no signs of clogging. The media is small, but they aren't low-micron units, so they shouldn't clog up quickly.

[2850Bounty]

SwampNut wrote:
Not according to the flow meter manufacturers. They all say you need a filter before the meter.

Carlos, is your main fuel filter not up-stream of the flow sensor?

This is a disclaimner if anything, and it's similar to an electrical device manufacturer's schematic showing a direct + battery connection, instead of the actual system connection.

Use the metal in-line filter to make you feel good......., but it is totally unnecessary if your main and less restrictive filter media is doing it's job!

.

[Guest]

boatworkfl wrote:
If installing Floscan meters you can download the instructions, better yet just call them and they will help.

Just for everyone's information I am not installing any, I don't have a boat at the moment.

It was just for discussion and so far some good info has come out of this.

Cheers

[Guest]

Carlos, is your main fuel filter not up-stream of the flow sensor?

Nope. All modern Mercruisers (IE, late 90s) that I have worked on have the filter mounted on the engine. This is why the OP asked the question to start with.

[dktool]

Nope. All modern Mercruisers (IE, late 90s) that I have worked on have the filter mounted on the engine. This is why the OP asked the question to start with.

+1, same with OMC,

1980's vintage Merc & OMC, same set up.

[2850Bounty]

SwampNut wrote:
Nope. All modern Mercruisers (IE, late 90s) that I have worked on have the filter mounted on the engine. This is why the OP asked the question to start with.

Understood.

Then are you suggesting that for those with this set up, that the little In-Line metal filter (the one with the very small filter media) become the "Primary" filter ahead of the flow sensor????

I sure hope not!

For those with engine mounted filters, it would appear that you have two choices:

• move that silly engine mounted filter from the engine and mount it remotely, and then install your flow sensor after this filter.
• add a primary "marine" filter just after the fuel tank outlet, and install the flow sensor between the two filter systems.

Personally, I DO NOT want my fuel filter mounted near an "on-engine" heat source!

Not for explosion reasons, but for keeping my fuel as cool as possible.

The factory "packages" or "bundles" these engines with the filter installed on-engine for simplicity.... not for the best function.

.

[Guest]

SwampNut wrote:
You cannot put the meters after the pump. You need to go between the thank and the pump. Therefore on most boats you need to install an additional filter before the meter. I used basic automotive 30 micron METAL BODY filters for this. They must be all-metal, no sight glass, plastic, etc.

I have been looking at boats, that is why the question. Engine mounted filters on all and the turbine installed on the line to the carb.

Not sure in my own mind why the turbine needs to be ahead of the pump it measures fuel going through the line based on what the engine consumes and the pressure is only 5-7 psi on carb engines.

Don't like the idea of these plastic parts anywhere in the engine compartment!!

[2850Bounty]

check737 wrote:


1.... Engine mounted filters on all and the turbine installed on the line to the carb.

2.... Not sure in my own mind why the turbine needs to be ahead of the pump it measures fuel going through the line based on what the engine consumes and the pressure is only 5-7 psi on carb engines.

3.... Don't like the idea of these plastic parts anywhere in the engine compartment!!

1.... I doubt that you'll see a gasoline engine flow sensor installed here.

2.... Flow is flow..... suction side or pressure side, but installing one on the pressure side poses some risks and hazards.

3.... And that is why the sensor is installed on the suction side of the fuel system.

.

[Guest]

Then are you suggesting that for those with this set up, that the little In-Line metal filter (the one with the very small filter media) become the "Primary" filter ahead of the flow sensor????

I sure hope not!

Yes, that's exactly what I'm suggesting. And have done. And it is working perfectly. It's only been about nine months and 500 gallons, but doing fine so far. There is no safety issue. The only potential issue is premature clogging of the smaller filter with either water or debris. Keep a spare on board.

Not sure in my own mind why the turbine needs to be ahead of the pump it measures fuel going through the line based on what the engine consumes and the pressure is only 5-7 psi on carb engines.

Don't like the idea of these plastic parts anywhere in the engine compartment!!

But you're recommending that people put the plastic parts on the PRESSURE side instead of the suction side? Why? In any case, boats should have a hard line from the pump to the carb, and you wouldn't want to cut that and put hose there instead.

Personally, I DO NOT want my fuel filter mounted near an "on-engine" heat source!

Not for explosion reasons, but for keeping my fuel as cool as possible.

The factory "packages" or "bundles" these engines with the filter installed on-engine for simplicity.... not for the best function.

Your theory is interesting and yet reality tells us it doesn't matter in any practical way at all.