"HOT" Facet Fuel Pump?

[roadnsky]

Well...

My final test didn't give any different results...

I used a 5-gal can of fresh fuel to run the engine and see if the pump ran any cooler.
But... exact same specs with the temperatures.

So, I'm out of ideas. I've replaced or tested everything:

• Replaced the pump
• Replaced the Racor filter
• Replaced the Polish filter
• Checked all hoses for kinks or blockage (they're all a year or less old)
• Checked all clamps
(5-gal test eliminated the fuel tank, but still tested...)
• Fuel tank pickup tube and screen are clear
• Vent tube is clear

I put a fuel pressure gauge in-line and the pump is doing 2-3 PSI as it's supposed to.

The only "untested" part of the fuel system is the carb.
It's just over a year old and I had it off in January, blew passages with air and cleaner (it was clean already)
AND, remember, the engine is running sweet. Absolutely no issues.

Unless anyone has another idea, maybe this is just how it goes during hot weather? I won't know until the Fall for sure though.
I sure hate to finish a thread like this with no real answer...

[rigspelt]

Electrical ruled out for sure? Can't be anything electrical inside the pump, because you have a new pump now. Good ground? You mentioned you were going to check the ground connection earlier, but did not mention it in the summary.

[roadnsky]

Electrical ruled out for sure? Can't be anything electrical inside the pump, because you have a new pump now. Good ground? You mentioned you were going to check the ground connection earlier, but did not mention it in the summary.

Oh yeah. Forgot to list that in my punch list.
I ran a new ground cable and used good Ancor term connectors.
Thanks for the reminder Rigs.

[thatch]

"A final thought"

Jerry,
Since your engine compartment is about as clean and apparently well thought out as any we've seen, I'm going to assume that it is also reasonably well "sealed up". Add to this your locale, (I've been near there) and what may be happening is nothing more than the old "oven" effect. The hot pipe section of your exhaust system, although wrapped, is still contributing a generous amount of heat into this fairly sealed box. You might try a home style, probe/temperature guage in the engine bay to see what the actual running temperature is in there. Most of the rest of the forum members A4s boats are sitting on some type of ocean water with a much "cooler" address than yours. The cure may be nothing more than to inject a little fresh air flow.
Tom

[roadnsky]

Tom-
Thanks. Very good thoughts and makes sense, but...

I've tried running with the entire engine compartment open. As well as with my blower exhausting.
During my 5-gal test I even had the side ports open in case there were any fumes from the can.
(There are a lot of access hatches to the engine room)

I got a Digital Thermo Gizmo and it's kinda fun to test different surfaces for temp.
(The head and manifold are interesting to watch)
Anyway, you're right. Even wrapped, that exhaust gets a little over 400° at it's high point.

All of that is why I'm starting to just think maybe it's running normal, but with air temps at 107+ it just gets "hot"...?

[ndutton]

. . . . . I'm starting to just think maybe it's running normal, but with air temps at 107+ it just gets "hot"...?

Jerry,
That got me to thinking, if the issue is purely environmental then dissipating the heat is the goal, no? A quick internet search turned up some very cool (cool, get it??) cylindrical heat sinks used by the radical radio control car enthusiasts. They come in a variety of styles, many with an onboard cooling fan and are reasonably priced, like $10 to $30. I found them at

http://www.rcplanet.com/Integy_Side_Mount_Heatsink_Fan_p/intc22480purple.htm

I have no idea what voltage the fans are but this suggestion is purely conceptual. Might work well on coils too.

Here's a pic as an example:

[Marian Claire]

What is the temp of the filter just upstream from the pump? Being in a similar location and with the same amount of flow as the pump it might be a good base temp to see if the pump is adding heat. Dan S/V Marian Claire

[roadnsky]

What is the temp of the filter just upstream from the pump? Being in a similar location and with the same amount of flow as the pump it might be a good base temp to see if the pump is adding heat.

Dan-
The Racor (upstream) is running about 98°
However, the polish filter (downstream) runs about 108° or so.
But I figure that is because the pump is actually heating up the gas before pushing it down.

That 98° temp seems to be the base, since that's what the Facet starts out at before it starts pumping and heating up.
So... maybe at work, it's heating up an additional 25-30 degrees?
The "hottest" reading so far has been 130°

Neil-
Not a bad idea. Thanks for finding that.
If I can't figure this out I'm thinking I might try that for the summer months.

Thanks boyz...

[rigspelt]

For what it's worth, I checked today when I warmed the engine for about 10 minutes to change the oil. Idled it up to 150 degrees then shut it down. Our on-engine Facet pump was not at all warm to touch. Air temp today humid 80F (27C), hatches were all wide open.

[roadnsky]

For what it's worth, I checked today when I warmed the engine for about 10 minutes to change the oil. Idled it up to 150 degrees then shut it down. Our on-engine Facet pump was not at all warm to touch. Air temp today humid 80F (27C), hatches were all wide open.

Well, I really feel in my gut something is going on.
I'm just missing it somehow.

I'll keep 'chewing on it' until it becomes apparent...

[thatch]

"A final, final thought"

Jerry,
Normally we are only concerned with pump flow and pressure but in this case it might be a good idea to do a vaccum check on your pump to tank lines. A normal combo fuel pump/vaccum guage should work just fine. The first place I'd check would be at the pump inlet and then I'd work myself back to the tank. If the vaccum reads nil at the pump then there's no reason to waste your time checking back to the tank. If however you are reading an appreciable amount of vaccum then I'm betting you will find some major restricting point somewhere upstream. This vaccum reading will change depending on fuel flow so it would be best to just disconnect the the fuel line at the carb and pump some fuel into a container while watching the guage.
Tom
P.S. Put out your cigar for this test....

[rigspelt]

What is the temp of the filter just upstream from the pump? Being in a similar location and with the same amount of flow as the pump it might be a good base temp to see if the pump is adding heat. Dan S/V Marian Claire

Or maybe if the fuel in the fuel tank is warm? Our tank is outboard near the hull and well away from the exhaust, so might be relatively cool before it even gets to the fuel pump??

Still assuming that Jerry's pump is too warm (and I am not convinced that we have authoritative information on that for sure yet) then what about the relative height of the pump, fuel tank and engine? Right now the pump is mounted on a bulkhead higher than the usual on-engine mount location. Is there a clue there? Could the pump be working normally, but increased pressure = increased fuel temperature and therefore increased pump housing temperature, the reverse of adiabatic cooling such as happens in the carb when the gas expands prior to ignition? I know Jerry measured normal fuel pump output pressure, but it might not take much perhaps? I'm just speculating.

I did some googling to try to learn more about engine gasoline or fuel pump temperatures, because I still think we need to know for sure if Jerry's pump temperature is something to work on. I did not find much that helps in this discussion, but did learn that gasoline temperature can so affect engine performance that some gasoline products with volatility characteristics suitable for the ambient climate change winter to summer. Hot rodder forums are concerned about delivering fuel cool enough to prevent vapour locking. There must be a pool of information out there somewhere that would help us understand desired temperature upper limits of fuel delivery systems, so we can figure out if Jerry has an issue or not.

Any chance the fuel pump is sucking air, making it work hard, but somehow not affecting engine performance??

[roadnsky]

Rigs-
Good thoughts. Got me thinking in a different direction.
The tank is aft of the engine near the transom.
But there's a water tank between it and the hull. No real extra heating going on there.
About half of the tank is higher than the carb.
The Racor is just about equal to the top of the tank as is the Facet.
Your discussion has me thinking maybe if I lower the Racor and the Facet so there's some gravity working the pump wouldn't work so hard.
(It is a 'pushing' device after all)

I too kept wondering about air, but can't figure out how it'd be getting in there.
Those hoses and clamps have been checked 3 times now.

I'm gonna follow Tom's excellent advice of back-testing with a vacuum gauge. Thank you Tom for that idea.
(I'm sure Dave would approve too)
I also think I'm gonna get some new hose just to rule out some kind of weird pinhole leak going on.

I'm in Chicago this week on business, so it'll be Saturday before I can get back to this.
I'm convinced that something is going on in that tank-racor-pump-carb system.
With these suggestions I've got new energy to start at the beginning and find it.
I'm just surprised no one else has ever had this before in our community...?

[roadnsky]

Bingo!

Found it!
One of the great things about this forum is when you find yourself landlocked for an extended period, you can surf here and get a small fix.
While stuck on an extra long business trip last week, I did just that.
Reading thru volumes of new and old threads.
During that time, one post mentioned "gravity flow" while talking about their fuel issue. It sparked an idea...

Sunday I looked at my setup, and sure enough, the Racor and Facet were mounted just slightly higher than the fuel tank.
So, being frustrated and out of ideas, I thought "Why not?"...

Lowered both of them about 4 inches putting them almost "Mid-Tank" level.
Fired up and headed out sailing.
My longest motoring was only about 20 minutes, BUT the Facet didn't get above luke warm.

My theory is that the "uphill" climb the fuel took to get thru the Racor to the Facet was just enough to make the pump work harder.
Causing it to run hot. But not enough head loss to cause any issues with the carb or engine performance.
Not sure if that's good science, BUT it's a theory until somebody else has a better one... (Hello? Dave?)

Anyway, for now, all's well again.
Except, of course, today I leave for another long business trip...

[hanleyclifford]

Jerry - Good to hear the news! Maybe there is something useful in those long business trips? Now, since you'e planning another...we have a number of perplexing issues still before the forum...