Tomcat fuel tank access woes

[squidslayer]

CBrats
On my 2007 Tomcat 255 Iast week I was having loss of power and rpms on my starboard Honda 150. I had to pump the primer bulb every couple mins when running fast but not at very low speeds  Its not the motor because it runs fine on an exterier fuel tank hooked directly to the engine.....and also runs fine though all fuel lines and filters when hooked to an exterier  tank. So its GOT to be the starboard fuel tank .The fuel line looks fine as far as  I can see towards the tank but I cannot get to where it connects. To get my boat back online I have  temp hooked the starboard engine to share the port fuel tank...both motors on one tank...it runs fine.
Now the big question....access to the starboard fuel tank feed tube/check valve for possible replacement or tightening. There is NO access to the tank on my boat. Taking all the side covers/hatchs off you cannot get to ,reach or even see the feed tube of the tank or really any part of the tank .The only way to access it is to or cut the whole fiberglass fish box out or remove the rear helm station then cut thru the fiberglass floor or cut the fiberglass bathroom/head floor out..
Has any other Tomcat owner had to access their fuel tanks yet?
Any thoughts or input from anyone would be deeply appeciated.

DickE
Bodega Bay
California

[Mike...]

[squidslayer]

Even if you take out the fish box
it is not directly over the tank.. The tank is directly under the rear helm and
Bathroom

[Mike...]

And the hatch under the Galley is too far forward to help?

If you can't get at it by removing the coaming box, and you can't get at it from the galley, then maybe cut a hole and install a round access hatch forward in the starboard fish box? Check out Dreamers photo album here for just such a mod.

Hopefully others here will have a less drastic suggestion.
---
mike

[Captains Cat]

Our 2006 TC has a round access hole/hatch in the step. I think I can see the hose connections through that. My side cockpit boxes are not removable, they are glassed in.

I currently have a problem with my stbd Suzi 115, will not idle, I can get it started and it'll run up to about 2500 RPM. I just replaced the low pressure fuel filter and the racors on both side. Fuel looks good I can see it in the LP filter at the back of the engine.

No trouble lights on the tach. Going to put new plugs in both engines this afternoon and see if that is the problem.

The first time I ran it after the filter changes, it ran and idled great. Hopefully, it's the plugs. Engines have about 275 hours on them and, to my knowledge, have never had new plugs.

Charlie

[matt_unique]

Dick - do you have round access ports just below the gunwales where the cockpit meets the cabin? I have two (one small and one large).

Also - can you remove your cockpit line storage boxes? Mine come out with 8 screws removed and provides good access and ambient light to the fuel tanks. I replaced one of my fuel pickup tubes due to a sticking check valve last year.

Your problem could also be with the fuel tank vent - if partially clogged it will siphon off fuel (due to vacuum pressure) at higher RPM's. The access ports I mention above allow you to access the fuel tank vent as well.

[Captains Cat]

Matt, from what I've read here on the site, all the TCs were built "individually" and there are MANY variations in the installations. My cockpit boxes (on the side) do not come out. Wish they did. I'll look through my round (about 10") access port in the step and see what I can see. I'll try to get a picture too. Gotta replace the plugs this evening anyway.

Charlie

[squidslayer]

[BrentB]

You might use hand pump on the fuel line to remove clogs from the ASV and fuel tank pick up tube. ASV has an one way spring loaded ball bearing to prevent gas siphoning outward. By disconnecting the fuel line near the stern and applying negative pressure constantly or in bursts will open the ASV and let fuel flow and might clear out debris. Use proper safety equipment and protection around gasoline. Collect gas in a jar and inspect. I would open the gas cap for venting. I would use a camera (fiber optic camera or scope, or I use USB web cam on a stick and notebook- poor man's scope) and check the fuel line and vent hoses from the tank to the top and check for kinks. Primer bulbs can be a problem, too and easy to replace and look at the quality and the end crimps. The internal filter might need to be changed. Same for the VST filter if your engine has one. it might have some fine buildup on screen reducing fuel flow and need a magnifier to see. Some clean and reuse. Some replace with new. If you have a fuel flow meter inline before the main fuel/water filter (Racor type), it should be inspected. If the Racor fuel head has 2 ports, one for the main and the other for the kicker, there might be a small air leak at any of the connections

[BrentB]

Another item to check is internal fuel line break down and sending bits and piece down stream and fuel filter collects it but the line is weaken and collapses under load

[squidslayer]

Thanx for all the input
the primer bulb was not collapsed when the problem occured which would mean an obstuction in the fuel line so no clogg ...It has to be an air leak
the engine runs fine running a separate fuel tank though all the lines and filters Inc the primer bulb. Fuel tank...need access..I am going to check the port tank which is under the cabnets back of the table ...check were the fuel pickup is .. and try to use it as a guide as to where to open up the bath floor for an access point... Hope I do not have to pull the head !

[matt_unique]

Hi Dick,
My fuel pick-ups are close to the intersection of the cockpit and the cabin. I can access them through the ports I described above. I can reach them from the circular port but tend to reach in through the line storage box holes.

Sorry to hear yours are not right there...bizarre...I figured things like the fuel tanks and fuel pickups would pretty much have to be the same on each of our vessels.

[BrentB]

Post an update

[squidslayer]

[quote="matt_unique"]Hi Dick,
My fuel pick-ups are close to the intersection of the cockpit and the cabin. I can access them through the ports I described above. I can reach them from the circular port but tend to reach in through the line storage box holes.

Matt
how far from the back of the tank is the pick up located ?
I assume it is in the middle of the aft part of the tank...your tanks must be mounted farther back than mine.....all I can reach from the in line box is the filler tube and vent tube which are on the starboard edge of tank. The rear of the tank on my starts right at the moulded fiberglass step and goes forwards under the bathroom. Is that how yours is?
and another ??? why do you even need an antisiphon valve when the fuel lines and engine are ABOVE the fuel tank???


The law states as follows....


§ 183.568 Anti-siphon protection.
Each fuel line from the fuel tank to
the fuel inlet connection on the carburetor
must:
(a) Be above the level of the tank top;
or
(b) Have an anti-siphon device or an
electrically operated fuel stop valve:
(1) At the tank withdrawal fitting; or
(2) Installed so the line from the fuel
tank is above the top of the tank; or
(c) Provided that the fuel tank top is
below the level of the carburetor inlet,
be metallic fuel lines meeting the construction
requirements of § 183.538 or
‘‘USCG Type A1’’ hose, with one or two
manual shutoff valves installed as follows:
(1) Directly at the fuel tank connection
arranged to be readily accessible
for operation from outside of the compartment,
and
(2) If the length of fuel line from the
tank outlet to the engine inlet is greater
than 12 feet, a manual shutoff valve
shall be installed at the fuel inlet connection
to the engine.

DickE

[Captains Cat]

Dick, I just took some pix through that inspection port, will post in the morning. I can see lots of stuff... I have no access through the cockpit side boxes, mine are glassed inl

Charlie