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Sea Wolf



Joined: 01 Nov 2003
Posts: 8567
City/Region: Redding
State or Province: CA
C-Dory Year: 1987
C-Dory Model: 22 Cruiser
Vessel Name: Sea Wolf
Photos: Sea Wolf
PostPosted: Tue Feb 21, 2006 2:21 pm    Post subject: Reply with quote

Thought I'd better post a warning and revision about the external fuel supply system shown in the earlier post above.

I took it to the lake yesterday and set ity up with the generator, etc.

It will raise fuel from the Racor filter and the tank below, as I could see this in the clear tubing.

However, the generator won't rev up when a load is applied. Removing the cap immediately solves the problem. My interpretation is that the fuel pump is so taxed by lifting the fuel that there's negative pressure in the carburetor, and when the main jet tries to supply fuel as the engine needs to rev up, it can't because the negative pressure won't let the fuel flow through the jet easily.

So it looks like it's back to the drawing boards. An external electric pump could be added, but that's a little dangerous if the float valve were to get stuck open or just not be able to handle the pressure.

Having another external tank at the genertor level might do the trick, but why bother with another tank, etc.

I may just use the hose and supply set up to refill the generator's tank by hand pumping so I don't have to carry an extra gas can.

I was told on the Honda 2000 Generator site (Yahoo Groups), that the generator will lift fuel 6 feet at sea level. Maybe so, but it has to do it better than I'm seeing so far.

They use these set ups on generators with RV's, but without lifting the fuel much, usually with the supply tank level with the generator.

Will keep you posted as developments occur.

Joe.

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Sea Wolf, C-Brat #31
Lake Shasta, California

"Most of my money I spent on boats and women. The rest I squandered'. " -Annonymous
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B~C



Joined: 31 Oct 2003
Posts: 2735
City/Region: S.W. WA
State or Province: WA
C-Dory Year: 1999
C-Dory Model: 22 Cruiser
Vessel Name: Blue~C
Photos: Blue~C
PostPosted: Tue Feb 21, 2006 7:32 pm    Post subject: Reply with quote

well durn it all, that would have been so nice to just tap into the mother tank. I've been preping the boat for the "Shasta Package". The fish harvesting station across the motorwell is now history, it will be replaced by something more suitable for generator parking.
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Ken
1999 22' boaterhome
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rogerbum



Joined: 21 Nov 2004
Posts: 5827
City/Region: Kenmore
State or Province: WA
C-Dory Year: 2008
C-Dory Model: 255 Tomcat
Vessel Name: Meant to be
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PostPosted: Tue Feb 21, 2006 8:46 pm    Post subject: Reply with quote

Joe,

It might be worthwhile to do a little experimenting to determine if the issue is pulling the fuel that high, restriction in the line or just pulling it that far. Depending on the flow conditions, length can be a huge issue. From my old days in physics, I seem to remember that pressure drop across a pipe or piece of tubing is a function that can be between an inverse power of 3 to an inverse power of 6 in length. That is doubling the length of a tube can generate 8-64 fold increase in the drop in pressure (I couldn't find the exact formulas and parameters online in 10-15 minutes of googling so the real engineers --- please help out). My point is that if the pressure drop is due to flow related friction and if you have more tygon that you really need for the hook-up, maybe just shortening the line will help. Also, if it is a pressure drop across the tubing due to turbulent flow in a long line, increasing the diameter of the tubing may also solve the problem.

If the problem is really due to having to raise the fuel up to the level of the generator (which I presume is above the tank perhaps sitting on a lazarette), then simply lowering the generator to the floor would result in proper operation. I realize that you don't want to run the generator on the cockpit floor due to the previously mentioned issues with regards to exhaust, but I am suggesting this as an experiment to determine the source of the pressure drop/problem.

Finally, if it's not the height difference and it's not the length, that might suggest that the brass shut off valve needs to have an enlarged orifice.

Just a few thoughts.

Roger on the SeaDNA

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Sea Wolf



Joined: 01 Nov 2003
Posts: 8567
City/Region: Redding
State or Province: CA
C-Dory Year: 1987
C-Dory Model: 22 Cruiser
Vessel Name: Sea Wolf
Photos: Sea Wolf
PostPosted: Tue Feb 21, 2006 10:47 pm    Post subject: Reply with quote

Roger-

Thanks for all the thoughts, all well worth checking out!

I'd planned to spend some more time trying different addjustments and doing some experiments to see if I could overcome the fuel feed problem, but wasn't in a situation to do it yesterday.

Unfortunately, I had my 6 month old Great Dane with me on the boat, and she's a little too immature aand impulsive to allow thoughful examination processes to proceed at a rate that can make meanngful observations, interpertations, and conclusions.

I can see the fuel feeding up through the tube, but will have to try and determine what is the source of restriction or limited flow.

The tubing is 3/8" and of the same diameter used in fuel supply lines for external tanks. In fact, some of them, used on smaller engines, have 5/16" lines. The line length is not much longer than commonly used in outboard external fuel supply lines, but can be shortened. I'll cut a few unnecessary feet off of it and see what difference it makes.

The valve is another good possibility for a source of restriction which can be temporarily removed.

One of the surprises that I found when initially using the set up was that the Yamaha quick coupling set up, which is copied after the OMC model, is very sensitive to alignment issues. It's a two prong set up, with one prong carrying the fuel and the other being an alignment and locking prong. It seemed to me that the two parts did not lock in their allgned positions well. Another potential source of problems.

Probably the best way to approach the issues would be to eliminate the valve, quick connect, extra tubing, and any other possible source of restriction to see it it will work without them.

If the set up is found to work with these possible sources of restriction removed, they can then be added back in one at a time to see their effect on the pressure drop to the generator's tank and the overall performance of the system.

If the experimenting warrants further investigation,, a sensitive vacuum gauge suitable for use around petroleum products could be placed in series along the line at bolth ends and at the middle sequentially to see if measurable presssure differences exist. This could be done again with the genertor moved from its position on top of the cooler next to the engine down to the floor to see the effect of elevation on the pressure differences. We should be able to determine from these separate measurements whether pressure drop is occuring along the line, and the effect of elevation differences on the pressure drop.


Lots of good fun to have in checking this out, as there's still a lot to be investigated and determined. Like Yogi says, "It's not over 'till it's over!"

Thanks!

Joe.
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Larry H



Joined: 01 Nov 2003
Posts: 2039
City/Region: Tulalip,
State or Province: WA
C-Dory Year: 1991
C-Dory Model: 22 Cruiser
Photos: Nancy H
PostPosted: Wed Feb 22, 2006 2:51 am    Post subject: Reply with quote

Joe,

Another possible restriction is the anti-siphon valve(if you have one). They are usually installed at the tank outlet and require some vacuum to open.

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Larry H

A C-Brat since Nov 1, 2003
Ranger Tug 27 'Jacari Maru'
Puget Trawler 37 ex 'Jacari Maru' 2006-2017
1991 22' Cruiser, 'Nancy H'--1991-2006
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Sea Wolf



Joined: 01 Nov 2003
Posts: 8567
City/Region: Redding
State or Province: CA
C-Dory Year: 1987
C-Dory Model: 22 Cruiser
Vessel Name: Sea Wolf
Photos: Sea Wolf
PostPosted: Wed Feb 22, 2006 8:57 am    Post subject: Reply with quote

Thanks, Larry, I'll include it in the inspection test program. I do know there's one in the primer bulb, of course.


Joe.
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B~C



Joined: 31 Oct 2003
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City/Region: S.W. WA
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C-Dory Year: 1999
C-Dory Model: 22 Cruiser
Vessel Name: Blue~C
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PostPosted: Tue Feb 28, 2006 10:12 am    Post subject: Reply with quote

hey, how's the R & D coming on the extended fuel tank?

I tried out the generator the other day on it's new & improved combination cockpit love seat/generator stand. I ran it for a while and noticed a large amount of fuel running out around the feet. That is bad. With a bit of research on the Yahoo site, I discovered that it's not uncommon for new units to overflow the carb in the econo throttle mode due to the float sticking. I ran the unit again and sure enough, no leak in full throttle, but overflows the carb at reduced throttle, I proceded to fix unit by dropping it about a foot followed by a sharp rap on the carb with a scewdriver handle followed by some choice verbage. All better now, no leak Smile
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Sea Wolf



Joined: 01 Nov 2003
Posts: 8567
City/Region: Redding
State or Province: CA
C-Dory Year: 1987
C-Dory Model: 22 Cruiser
Vessel Name: Sea Wolf
Photos: Sea Wolf
PostPosted: Tue Feb 28, 2006 11:19 am    Post subject: Reply with quote

Ken-

I see you're a devout advocate of the BIGGER HAMMER SCHOOL OF THOUGHT, eh? Drop it from increased heights untill all is well! Sounds like the Soviet space program's landing scheme. We'll have to ask Don if the Navy has such an emergency operations program to deal with stuck hatches, missle tube doors, and the like by running the ship into a seamount at all head full.

I've fixed the remote set up by examining all the possible restriction points and re-sealing the cap to the generator, but haven't had a chance to test it out yet, which I'll probably do later this week.

Yesterday I installed the red 12 v LED rope lights in the cabin, added a interior handle above the dinette berth, and re-swedged the cable on one downrigger.

Will let you know how the tests on the remote tank set up come out ASAP.

Ever hear of a Randy Newman song "Let's Drop the Big One and See What Happens?" A Cold War protest song. He was referring satirically the the not so kindly Mr. H. Dr. Strangelove would have probably been a charter member of the BIGGER HAMMER SCHOOL.

Joe.
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iggy



Joined: 17 Feb 2006
Posts: 245
City/Region: Hillsboro, OR
State or Province: OR
Vessel Name: Edward Gallaher
PostPosted: Tue Feb 28, 2006 12:54 pm    Post subject: Reply with quote

I also don't have my physics book in front of my, but I believe Pouiselle's Law shows that mass flow increases with radius^4. That is, a slight increase in radius makes a HUGE difference in flow.

Professor hat on:
This is important in cardiovascular physiology when relating relative blood flows in capllaries, small veins, and larger veins (or arteries). Flow rates are -very- low in small-diameter capillaries, providing for nutrient and gas exchange (assuming not too much CO in the system; see previous messages). The arterioles are the smallest arteries, just before the capillaries. Modest increases in arteriolar diameter lead to -huge- increases in blood flow, e.g. during muscular exercise. (2x radius = 16x flow! Or more realistically, a 10% increase in radius leads to a 46% increase in flow.)
Professor hat off.

Having said all this -- I still suspect tank height is the main issue here . . . Wink

Ed
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Sea Wolf



Joined: 01 Nov 2003
Posts: 8567
City/Region: Redding
State or Province: CA
C-Dory Year: 1987
C-Dory Model: 22 Cruiser
Vessel Name: Sea Wolf
Photos: Sea Wolf
PostPosted: Tue Feb 28, 2006 1:52 pm    Post subject: Reply with quote

Fun to play with!

Normal atmospheric pressure at sea level is approx. 14.7 lbs / square inch.

This will push water up into a barometric tube about 34 feet. (Some of the original barometers were water tubes on the side of buildings.)

Gas is approx 7/10 as dense as water, hence it will go up 10/7 as far as water = 10/7 x 34 = 48.5 feet.

The lift required in the boat is about 2 feet.

The proportion of the lift available to that required is 2/48.5, = 0.04, or 4%.

4% x 14.7 lbs / sq inch = 0.588 or .6 lb / sq inch.

So what does this mean? I'm not 100% sure either! But it does seem low. The apparatus did lift gas in the first test, but I suspect the difference in pressure inside the carburetor due to the lifting process cut the supply of gas pressure to the main jet down enough to limit the response of the motor to the added electrical load. We'll find out by leveling out the generator with the gas tanks.

The gas lines and componednts are all normal external gas tank elements or the equivalent in size, and the (cut down) length is no longer than commonly found in gas supply systems.

Time for some testing!

Joe.
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Papillon



Joined: 31 Mar 2005
Posts: 949
City/Region: DeBary, Fl. *On the St. John's River*
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C-Dory Year: 1993
C-Dory Model: 22 Angler
Vessel Name: Papillon
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PostPosted: Mon Apr 17, 2006 10:48 pm    Post subject: Reply with quote

Joe:

Quote:
Time for some testing!



Well inquiring minds want to know....did you ever perform the test...is there a "rest of the story" here? Your last post was in Feb, 06...it is now mid April, 06......I know you are not on the clock but please don't leave us hanging.

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1993 Angler-02' 115 Suzuki 4 Stroke
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B~C



Joined: 31 Oct 2003
Posts: 2735
City/Region: S.W. WA
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C-Dory Model: 22 Cruiser
Vessel Name: Blue~C
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PostPosted: Mon Apr 17, 2006 11:03 pm    Post subject: Reply with quote

Joe, inquiring minds want tt know

I purchased the Harmony gas cap, sealed it up and installed a honda fuel fitting for use on our vacation. We never ended up having to use it on the generator but before we hit the road for home I discovered that the cap fit nicely on my gas can. I just unhooked the fuel line from the engine and hooked up to the gas can and drew out a couple of cans worth of fuel. I left there with a full tank in the truck and near empty tanks in the boat. A very handy, but slow, method of draining the boat tanks Smile
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Sea Wolf



Joined: 01 Nov 2003
Posts: 8567
City/Region: Redding
State or Province: CA
C-Dory Year: 1987
C-Dory Model: 22 Cruiser
Vessel Name: Sea Wolf
Photos: Sea Wolf
PostPosted: Tue Apr 18, 2006 1:09 am    Post subject: Reply with quote

WhalerGoFar-

Thanks for the reminder! I forgot to report when I finally found a time between rainy periods to fiddle with the set up. Embarrased

What I found out after some experimentation was that there didn't seem to be any real restriction in the gas flow along the line, but that the seal in the gas cap on top the generator was leaking some air, destroying part of the vacuum that pulls the fuel along the line. The clear fuel line doesn't show this, of course, because it preceeds the cap and tank which are opaque. I know thee are some inconsisencies between this conclusion and the list of possible causes we proposed earlier, so it's possible some other factor involved was changed or corrected inadvertently along the line. Angry

Just had to re-seal it with a Permatex gas compatible sealer after making a thicker, more supple Neoprene gasket from blank stock which gave me a better seal. Thumbs Up

The generator will now pull gas from the tanks readily while sitting on top of a 120 quart cooler in fron of the engine well. Wink

Thanks for reminding me!

Joe.
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nmitch2859



Joined: 28 Apr 2013
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City/Region: virginiabeach
State or Province: VA
C-Dory Year: 2007
C-Dory Model: 25 Cruiser
Vessel Name: Delfin
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PostPosted: Tue May 12, 2015 4:56 pm    Post subject: Reply with quote

I did tap into the primary fuel filter. I used a I/4 inch boat gas shut off valve. I did use a primer bulb and I did not have any leaks. I did not have the main going to check for problems. I did think that the 150 fuel pump should be able to pull gas from main tank, then the gen should not have any fuel starvation problems. I did it that way so I would not have to have a tank just for the gen. At this time I do not have any pictures. Neal
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thataway



Joined: 02 Nov 2003
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City/Region: Pensacola
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C-Dory Year: 2007
C-Dory Model: 25 Cruiser
Vessel Name: thataway
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PostPosted: Tue May 12, 2015 9:35 pm    Post subject: Reply with quote

OK, Neal, old thread resurrected! Does your Honda pull from the fuel tank? The outboard fuel pumps are much different than the small vacuum operated pump on the Honda generator. Joe got his to work on a 22, with the generator on top of a cooler inside the boat (not a good place because of CO issues). The top of a fuel tank on a 22 is only a few inches below the top of the splash well pan. We know that the Honda EU series will pull fuel about 2 feet, but it is rumored to pull up to 6 feet. The issue in the standard 25 is much different than in the standard 22. (The 25 has the fuel tank under the cockpit soul, the 22 the fuel tanks are much higher.).

We run our EU 1000 2 to 4 hours daily when using the freezer and refer. 90% of the time we put the generator on shore, some distance from the boat. It takes less than a tank of fuel to charge up our batteries, etc, so we don't need an aux fuel tank.

Why is the generator off the boat? Noise, and exhaust fumes are the main reasons. On the Tom Cat we used the EU 2000 on the swim step, and had the fuel tank at about the same level. There were no problems.

Be safe--CO, fumes, fire and gas hazards. Let us know how the fuel pump pulls the fuel up from the tank on the 25.

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Bob Austin
Thataway
Thataway (Ex Seaweed) 2007 25 C Dory May 2018
Thisaway 2006 22' CDory November 2011 to May 2018
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