Yam fuel flow sending units 2005ish....

[oldmako69]

Can these mofo's be opened up? I only have single engine FF readings at the helm. Either that or these are the most fuel-efficient engines on the planet. 3600 RPM, 30 knots in an 8000-pound boat, 8 gals per hour...RIGHT. P.O. was convinced that was actual-factual data.

I axe because I wonder if the impeller might just be gummed up or mechanically stopped. The boat sat for almost a decade. New ones aren't exactly cheap and I am, so there ya go. Off all my gozinta's in grade school, I am particularly adept at "times two".

OR....is there a setting perhaps on the display to change it to two engines? Kind of like Knots/MPH etc.
***Edit...yes there is, I just found out. Pretty sure mine is set properly and I have a dead unit, but will monkey around with it.


I will endeavor to dig for that info.

Thanks for any input and or ridicule.

[fairdeal]

unless its my imagination,
I seem to recall a thread here where someone 'removed the cover of the sensing chamber' ?
tiny tamper-resistant Torx screws?
to free up a paddlewheel driving a Hall Effect sensor ?

[boscoe99]

Can these mofo's be opened up? I only have single engine FF readings at the helm. Either that or these are the most fuel-efficient engines on the planet. 3600 RPM, 30 knots in an 8000-pound boat, 8 gals per hour...RIGHT. P.O. was convinced that was actual-factual data.

I axe because I wonder if the impeller might just be gummed up or mechanically stopped. The boat sat for almost a decade. New ones aren't exactly cheap and I am, so there ya go. Off all my gozinta's in grade school, I am particularly adept at "times two".

OR....is there a setting perhaps on the display to change it to two engines? Kind of like Knots/MPH etc.
***Edit...yes there is, I just found out. Pretty sure mine is set properly and I have a dead unit, but will monkey around with it.


I will endeavor to dig for that info.

Thanks for any input and or ridicule.

If one of the two sensors is inoperative, or the wiring to the gauge is defective, then the gauge will think it is a single engine application and only report fuel flow for the one motor that it sees.

Wiring is generally the issue when this happens.

[99yam40]

I believe the FF sender puts out a pulse.
I am not sure if a meter set on Hz could read that, but might be something to try at the gauges

[pstephens46]

Y’all can keep yer paddle wheels. None for me, thanks.

[pstephens46]

[boscoe99]

Y’all can keep yer paddle wheels. None for me, thanks.

You could use a good paddling yourself for that comment.

Are you an ultrasonic fuel flow man?

[pstephens46]

You could use a good paddling yourself for that comment.

Are you an ultrasonic fuel flow man?

I’m a fill up the tank and look at gas guage a couple times a day guy.

[boscoe99]

I’m a fill up the tank and look at gas guage a couple times a day guy.

That often huh?

Have you been reading about your Boeing friends over in Charleston? They are taking some hits about poor quality.

[pstephens46]

That often huh?

Have you been reading about your Boeing friends over in Charleston? They are taking some hits about poor quality.

Building planes in Charleston is probably like building cars in Montgomery AL.

[99yam40]

It is always good to fill up before heading out.
some people's memories are not too good anymore, and believing a gauge should be OK for most of the time

running out of gas would be a pain in some places

[FabricGATOR]

oldmako69, if you can manage, if you have enough slack, plug the opposite sensor into the opposite flow scan transducer and vice vesa. Run one engine and then the other to see if that same fuel source is registering or if it swapped to the other engine. If it moved, then the one side of the wire harness is dead.

I found that I had a poor connection at the three prong plug in the wire harness. I reterminated that side of the fuel flow harness with a new connector and they have been working reliable for going on about six years now.

Please let us know what you find and or if you find it is your transducer and you open it, let us know how that goes as well.
Need a new terminal connector kit? I know a source for that as well.
BonChance!

[oldmako69]

Many thanks for that suggestion. I'll pull and clean the connectors first just to knock out the easy and obvious. If no luck, I figure that I can just swap the entire unit out, P to S, to try and isolate the problem. I've got a birdnest of crap in my bilge. Whoever rigged this boat should find a new line of work. Last week I pulled about 8 feet of excess fuel line out of the bilge. It was looping all over the place. I also removed the Main / Aux tank selectors. I don't use the Aux tank. And I pulled all the associated fuel lines for the aux tank as well, downstream from the selector valves. From my extensive reading on the web, these engines are notorious for having idle cut-out and other fuel delivery issues. My goal is to eliminate as many possible locations for the siphon to break or leak between the lift pump and the fuel tank.

Last week I also pulled the Racors and sanded the hell out of the mating surface between the top casting and the spin on. Sure enough, the gas had eaten the paint and the surfaces were crudded up. I figure that this is a fine point for air to enter the system and cause issues. I hoped that I found my smoking gun for my current issue but no so fast. The lift pump on the port engine is dead or at least is not getting a proper signal to run. It does not cycle on/off when at idle. So, next item is to change out that pump.

At some point, I also plan on replacing all the fuel lines from the VST to the injectors. Last year my VST screen was full of tiny black particles which I figure are the innards of the fuel line suffering from the e10.

[99yam40]

does the pump get voltage to it but not run?
should be 12+ to it at key on, but ecu should toggle the neg to make it run
but then I do not know what motors are in this rig

[FabricGATOR]

Many thanks for that suggestion. I'll pull and clean the connectors first just to knock out the easy and obvious. If no luck, I figure that I can just swap the entire unit out, P to S, to try and isolate the problem. I've got a birdnest of crap in my bilge. Whoever rigged this boat should find a new line of work. Last week I pulled about 8 feet of excess fuel line out of the bilge. It was looping all over the place. I also removed the Main / Aux tank selectors. I don't use the Aux tank. And I pulled all the associated fuel lines for the aux tank as well, downstream from the selector valves. From my extensive reading on the web, these engines are notorious for having idle cut-out and other fuel delivery issues. My goal is to eliminate as many possible locations for the siphon to break or leak between the lift pump and the fuel tank.

Last week I also pulled the Racors and sanded the hell out of the mating surface between the top casting and the spin on. Sure enough, the gas had eaten the paint and the surfaces were crudded up. I figure that this is a fine point for air to enter the system and cause issues. I hoped that I found my smoking gun for my current issue but no so fast. The lift pump on the port engine is dead or at least is not getting a proper signal to run. It does not cycle on/off when at idle. So, next item is to change out that pump.

At some point, I also plan on replacing all the fuel lines from the VST to the injectors. Last year my VST screen was full of tiny black particles which I figure are the innards of the fuel line suffering from the e10.

I would try moving the fuel flow transducers as a last resort. If I have a sealed (non leaking) fuel system, the last thing I want to do is open myself to the possibility of a fuel in the bilge leak.

What I was trying to say above, was simply connect the left transducer to the right transducer wiring harness and vice versa. **Better yet* unplug one of the transducer right at the transducer and run the other engine. Do you show fuel burn? Then do the same thing other side.... Now you know which transducer is inop... NEXT, try to connect (electrically) the suspected inop transducer to the known good wiring harness side and run that engine (the engine connected to the suspected, of course).
If it works then you know it is that gauge's wire harness side is at fault. If it does not work then you determined that it is actually the transducer and you can address that accordingly.



I would rethink the usefulness of your AUX tank, especially if you are suffering E-10. many will folks say I am playing with fire, but I use E-10 pump gas all day long T R O L L ing on the cheap, then when I get under the bridge, I switch to my AUX tank and flush my entire fuel system with Rec-90 (alcohol free) fuel. The racors, fuel flow transducers, bulbs... everything gets about a three to five gallon flush from the Roosevelt bridge back to the boat ramp.

You said "lift pump" are you talking about the remote oil tank lift pump? I don't remember what engines you are powered by, 2 stroke? I just assume you are talking twins. Perhaps what you say about lift pumps are a four stroke thing that I know little about (and hope I never do)

Let us know what you find...

frustrating that on a boating and fishing forum you cant use the word T R O L L I N G.. let alone easily define a number between twelve and twenty. Silly puritans.