Re-doing Fuel Hose Rigging on Twin Engine Boat

Repair or modification of Boston Whaler boats, their engines, trailers, and gear
rnln
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Re-doing Fuel Hose Rigging on Twin Engine Boat

Postby rnln » Fri Dec 10, 2021 4:59 am

I recently acquired a 1987 Revenge [later disclosed to be a 22-foot hull] with twin Yamaha 70-HP Precision blend two-stroke-power-cycle engines. The fuel tank rigging originally was two hose barbs with a separate hose to each engine. Some of the hoses and parts are there; some are gone. I also received a box of mismatched parts. Since the fuel hose rigging is a mess, I am ready to redo it. A nice buddy's opinion was fuel hose rigging would be kept the way it originally--two separate fuel lines.

Q1: should the fuel lines be rigged as follows: one large diameter hose to a fuel-water separator filter from the fuel tank; then two separate hoses to each engine from the fuel-water separating filter?

ASIDE: I don't know if I can make these older Yamaha engine run and last. I may have to re-power. If I were to re-power the 1987 REVENGE [of unspecified length] I would use a single engine. If that occurs, then having installed one large hose from the tank to the fuel-water separating filter will save me from having to re-do that part of the fuel hose rigging.

Q2: in your opinion, how would you re-do the fuel rigging?

Thank you.

jimh
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Re: Re-doing Fuel Hose Rigging on Twin Engine Boat

Postby jimh » Fri Dec 10, 2021 7:34 am

From your narrative, I infer that at the fuel tank pick-up fitting there are two fuel hose barbs. That sounds normal for a Boston Whaler boat that would have been rigged with twin engines.

The method of having completely separate fuel hoses from the fuel tank to the twin engines gives redundancy and eliminates a single-point-of-failure. Because having twin engines is generally done to provide redundancy, keeping the two sets of fuel hoses from the tank completely separate to each engine is a good idea.

Your narrative does not mention if there is a fuel-water separating filter installed now.

Typically the manifold into which the filter is attached will have two inlets and two outlets. This would permit one fuel-water-separating filter to handle two engines. However, using one filter creates a single-point-of-failure. To preserve redundancy and isolation of the fuel systems for each engine, using two fuel-water-separating filters is better. On the other hand, to carry a spare replacement filter is simple and inexpensive, and the concern about failure of the single filter is reduced.

There are other considerations in fuel hose rigging. With twin engines, you might run only one engine at a time. If there is any common point in the fuel system between the two engines, there should be some means to prevent the engine that is running from sucking fuel out of engine that is not running. Usually there will be a primer ball in the fuel hose, located very near the engine (and oriented vertically). In twin engines, assuming each engine has its own primer ball, the check valves in the primer ball should stop the running engine from sucking fuel out of the non-running engine.

Another consideration in fuel hose rigging: minimize the complexity. The more components spliced into a fuel hose line, the more potential places for air to be drawn in to the fuel system.

FUEL HOSES: be sure to use new fuel hoses that are USCG rated for use with alcohol-gasoline blended fuels. More recently the fuel lines must also comply with permeability ratings. Generally a black rubber coated fuel hose from a prime manufacturer is the best. And don't be shocked at the cost of this hose on a per-foot basis.

PRIMER BULB: Use OEM-quality primer bulbs, not cheap aftermarket ones.

HOSE CLAMPS: Use proper hose clamps. Typically a metal strap screw clamp is used (also called a Jubilee clamp in the UK). Use marine-grade stainless steel clamps:
https://www.grainger.com/category/pneumatics/hose-clamps/worm-gear-clamps

There are some decent plastic clamps with a gear-tooth ratchet design that can be used:
https://www.dripdepot.com/item/global-half-inch-ratchet-clamp

Metal Oetiker clamps can be used. You can buy Oetiker clamps at stores like Home Depot:
https://www.homedepot.com/s/oetiker%2520clamp?NCNI-5

The tool needed is $15:
https://www.homedepot.com/p/Apollo-Poly ... /203053310

If you are going to re-do the whole fuel system, look into Oetiker clamps.

ASIDE: assuming the Yamaha 70-HP engines are also c.1987, they are really nice engines. They will probably run well as long as you provide good fuel and good oil to them. About the only influence that would reduce their service life is extensive hours running in warm saltwater.

I used to own a 1987 REVENGE 20 W-T rigged with twin 1987 Yamaha 70-HP Precision Blend two-stroke-power-cycle engines. I sold it about fifteen years ago, but as far as I know the engines are still running. Each engine had its own primer bulb and its own fuel hose that ran directly to the fuel tank pick-up barb; there were two barbs at the tank. If there was a fuel-water separating filter, there was only one filter.

rnln
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Re: Re-doing Fuel Hose Rigging on Twin Engine Boat

Postby rnln » Sat Dec 11, 2021 7:12 am

Hi Jim--thanks for taking time to revise my questions and help with all the valuable info.

The boat length is 22-feet.

After reading your long explanation on multiple areas, I think I will keep two separate fuel lines, and just refresh the parts.
In the box of parts, I have two fuel-water separator filters. One is new, and one is used. I think I will keep both but replace the used filter element.

Another question:

Originally, the two fuels hoses are going from the tank through the aft bulkhead of the fuel tank cavity] to the live well, and then from there through the [Starboard bulkhead of the live well] to the [starboard aft cockpit sump]. Two copper pipes are used for this part of the route.

I am instead thinking about [modifying the path of the fuel lines so they would pass though [the aft bulkhead of the live well and go directly to the transom splash well.]

Q3: Is [the routing of the dual copper fuel hoses] better [if the hull is modified so the lines go directly through the aft bulkhead of] the live well to the transom [splash] well [and thence] to the engines?

jimh
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Re: Re-doing Fuel Hose Rigging on Twin Engine Boat

Postby jimh » Sun Dec 12, 2021 10:19 am

rnln wrote:Q3: Is [the routing of the dual copper fuel hoses] better [if the hull is modified so the lines go directly through the aft bulkhead of] the livewell to the transom [splash] well [and thence] to the engines?
I don't think your plan is an improvement. I will explain my opinion below.

The original rigging typically seen on a 22-foot OUTRAGE/REVENGE hull is for the fuel lines to exit at a high point at the starboard aft corner of the fuel tank cavity, and enter into the aft cockpit livewell just below the deck cover level. These lines usually cannot even been seen unless you bend over and stick your head into the aft cockpit livewell and look to Starboard. This routing keeps the fuel lines high and dry. From there the lines escape from the livewell, making a 90-degree bend to Starboard, cross over the top of the aft cockpit Starboard sump, and rise above the deck level through the hatch. The hatch is typically wooden in older boats, and a notch or cutout in the hatch has been made expressly for this purpose, that is, to allow fuel lines and other rigging to exit from the rigging tunnel and continue to the transom. This point is generally where the fuel lines would enter the input port on the manifold of a canister-type fuel-water separating filter.

The copper lines you report as the original rigging on your boat are somewhat unusual, but I have heard of the use of copper lines at this point. The run from tank fuel outlet to filter manifold input should not have any need to be moved or to be particularly flexible. The hoses should be more or less fixed in position.

From the fiter manifold output to the engine the fuel hoses are always rubber and flexible. The primer bulb is inserted into the hose just before the hose enters the engine. The primer bulb should be oriented vertically, and the embossed arrow on the primer bulb body should be pointing skyward.

I don't see any particular advantage to your proposed modification, particularly on an older 22-foot hull. The pre-c.1990 22-foot hulls were molded with a very narrow engine splash well--what is called a sink-style engine splash well. I am not sure exactly where your proposed new hole or tunnel between the aft end of the aft cockpit livewell and the engine splash well would be made. I think the new tunnel have to be very carefully located so it would not miss the small splash well. Once the fuel hoses get into that small splashwell, where would you mount the fuel-water separating filter (or filters)?

With a canister-type filter, you must allow for enough room under the filter to be able to unthread the filter and remove it from the manifold. Also, you certainly DO NOT WANT the fuel-water separating filters to be located in an area where they are going to be continually exposed to the sea and seawater coming aboard. The filters are usually mounted as high as possible on the hull Starboard inwale, under the gunwale. This keeps the filter and hoses out of the water and gives plenty of room under the manifold for the removal of the canister filter.

Your proposal adds a new tunnel that would pass through an area of the Unibond hull that is likely to be mostly foam. You would have to take some precautions to prevent water from entering into this tunnel and soaking into the foam. That is more work, and I don't see any advantage to be gained.

Finally, there are many thousands of 22-foot hulls with the original fuel line rigging, and there does not seem to be a hue and cry for changing it.

jimh
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Re: Re-doing Fuel Hose Rigging on Twin Engine Boat

Postby jimh » Sun Dec 12, 2021 10:37 am

ASIDE: since the boat under discussion is a REVENGE, the helm is located on the Starboard side of the boat, not on center as with an OUTRAGE model. The location of the helm on Starboard creates an opportunity to move all the electrical rigging for the engines to run under the Starboard gunwales to the helm from the transom. This will get all the electrical cables out of the rigging tunnel.

On my REVENGE 22 the only rigging that remains in the rigging tunnel is the hydraulic steering cables, and one electrical cable for the SONAR transducer. The SONAR transducer cable is intentionally routed in the rigging tunnel while all other electrical cables are routed under the gunwale. The purpose is to isolate the SONAR transducer cable away from all other electrical cables in order to minimize any electrical signs from the other cables entering into the SONAR transducer cable and creating interfering signals.

In older outboard engines the engine rigging harness may include a circuit for engine shut-off than is carrying a rather high-voltage (about 300-Volts AC) output from the alternator coil windings that is used in creating the spark ignition. The safety shut-off lanyard switch at the helm is wired to throw a short circuit across this ignition coil signal to stop the engines. If you run the SONAR transducer cable in a bundle with the engine wiring harness, the strong AC signal will cause interference with the SONAR signals.

When all the engine wiring harness rigging is moved out of the rigging tunnel, there is plenty of room left for two fuel lines to pass out of the rigging tunnel and through the cut-out in the hatch.

rnln
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Re: Re-doing Fuel Hose Rigging on Twin Engine Boat

Postby rnln » Sun Dec 12, 2021 4:49 pm

JIMH--thank you for all the information and your effort and time to put the replies together; they are important to me. I appreciate it.

After a long talk with Vance today on another topic--and thanks Vance--he has similar opinion. I will not reroute the fuel lines. I will just refresh them and make sure to tightly seal them.

Bulldog
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Re: Re-doing Fuel Hose Rigging on Twin Engine Boat

Postby Bulldog » Thu Dec 16, 2021 8:08 pm

Jim's old 1987 Revenge 20 is alive and well still running the 70HP Yamaha engines which still have great compression, and are a nice light weight engine. The dual reduntant fuel system is a great idea, as are the dual engines, my Revnge has Springfield Marine brackets and I have a rear seat mounted in the splash well, with stainless fuel filter bracets, having the rear seat in splash well gives me the floor space of a 22 footer. Jim's advice was all spot on.....Jack

rnln
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Re: Re-doing Fuel Hose Rigging on Twin Engine Boat

Postby rnln » Fri Dec 17, 2021 4:57 am

Thanks Jack,
Do you have any pictures on hand and don't mind to post? I would love to see different setups
Thanks.

jimh
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Re: Re-doing Fuel Hose Rigging on Twin Engine Boat

Postby jimh » Fri Dec 17, 2021 7:14 am

Here is a link to 40 pictures of my old boat, now Jack's boat. You can see some of the twin engine rigging:

https://continuouswave.com/jimh/Revenge20WT/

Jack also has made some nice improvements in the boat after he bought it.

Vance's Revenge
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Re: Re-doing Fuel Hose Rigging on Twin Engine Boat

Postby Vance's Revenge » Mon Dec 20, 2021 10:50 am

That is a very nice boat! I sure wish we had more Classic Whalers out here on the west coast. It is very hard, or nearly impossible to find a model we want in good condition.

rnln
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Re: Re-doing Fuel Hose Rigging on Twin Engine Boat

Postby rnln » Thu Dec 23, 2021 4:45 pm

wow, it is so... the same as mine, engines too, except mine doesn't looks as clean and doesn't have hydraulic steering.
Thanks Jim

jimh
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Re: Re-doing Fuel Hose Rigging on Twin Engine Boat

Postby jimh » Fri Dec 24, 2021 10:22 am

Vance's Revenge wrote:I sure wish we had more Classic Whalers out here on the west coast. It is very hard, or nearly impossible to find a model we want in good condition.
The irony about my old REVENGE 20 W-T boat, which I found in Michigan, is that it was originally sold in California, which is how it came to be on a PACIFIC brand boat trailer. After several years in Michigan, the boat moved farther East and I think is now on the Atlantic coast.

rnln
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Re: Re-doing Fuel Hose Rigging on Twin Engine Boat

Postby rnln » Thu May 19, 2022 5:42 pm

I have a question on the fuel hoses/pipes...

On the pic attached, the live bait well. The left of the pic is the fuel tank compartment. Top of pic is the drain sum. The arrow is pointing to the little brass (or copper?) fuel pipes. There were 2 x 5/8 hoses running from the gas tank through the wall (on left of pic) and clamped to the 2 little copper/brass pipes behind the brown plastic cover. As you can see, the copper pipes go through the wall and come out on the drain sum. Then they come up on the far top.

My question is should I keep using the same configuration with the little copper/brass pipes or should I run the hoses from gas tank all the way out? Any pro and con?

Thanks in advance.
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Vance's Revenge
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Re: Re-doing Fuel Hose Rigging on Twin Engine Boat

Postby Vance's Revenge » Thu May 19, 2022 8:06 pm

If there is no corrosion the original design should be sufficient. My concern is how are the tubes sealed in the wall between the Fish Box/Well and the Drain sump? That pass through needs to be sealed well so water doesn't get around the tubes and into your foam core.

rnln
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Re: Re-doing Fuel Hose Rigging on Twin Engine Boat

Postby rnln » Fri May 20, 2022 7:57 am

Hi Vance,
If I use the same 2 little brass/copper tubes, I plan on using 1" fiberglass tube and marine-tex it there, the way you did your through hull tube. It will seal the water not to come into the wood/foam, but letting water go between the drain sum and the live well.
If it is better to use 5/8 fuel hoses, I will have 2 x 1" fiberglass tubes there instead of 1. Each for each hose.
What do you think?