Almost at wits end!!

[newellchunker]

I've got a 1982 Cobia 21' CC w/ a '97 Tohatsu 140. When I bought the boat it had a 140 Johnson that was killing my billfold. I bought the Tohatsu, decided to check fuel tanks since boat had been sitting for a few years. Main tank full with 50 gallons of OLD GAS, drained it and proceeded to drain reserve tank-25 gallons decent gas . I the installed fuel- water seperator and new fuel filter. Add new gas and try her out....made it around an 8th mile before it acted like it ran outta gas, switched to reserve and it ran like a champ...46 miles worth! Came home blew the lines out w/compressor and tried it again.....made it approx. 4 miles and again acts like outta gas. Changed fuel- water seperator filter (brown crud) installed new fuel line from tank, new filter and tried again, about four miles again. It will run great on small tank. I need to be able to run large tank for more distance. Has anybody got any ideas what could be the problem. THANKS!!

 

[Salmonseeker]

Re: Almost at wits end!!

Make sure the fuel vent is not clogged or turned off. To check this just loosen the gas cap when running to allow air in the tank. If this stops the problem your tank is not vented properly.<br />I would try that first to eliminate that possible problem.<br /><br />Jay

 

[newellchunker]

Re: Almost at wits end!!

I should have mentioned that also, I took the gas cap off while my fishing partner was at the helm, no effect! (however, the boat was weighted towards the rear and I doubt any air could have entered with full tank of fuel?) Any opinions on the possibility of vent line needing to be replaced?? Anyone ever heard of that kind of hose (5/8) collapsing when there was a suction through it? There is also a new switch valve...2 inlets, 1 outlet that runs from both tanks into the fuel-water seperator out to inline filter to engine. Hope this additional info helps. I'm about ready to sell her!

 

[Jan Z]

Re: Almost at wits end!!

Take a peek at this<br /><br /><br /> http://www.thelog.com/news/newsview.asp?c=171312

 

[Bondo]

Re: Almost at wits end!!

If you remove the Tank Outlet Fitting,.......<br /><br />You'll Probably find that the Pickup Screen,+ the Check-Valve are Both Plugged............<br />The Check-Valve is hidden in the Hose Barb........

 

[newellchunker]

Re: Almost at wits end!!

I appreciate the responses, however it is an aluminum tank and I have removed the pick-up (outlet) and checked...there was little pieces of trash but nothing to clog the screen. Also the check valve had been removed/ cleared. These are the main reasons for my frustration!!!

 

[Solittle]

Re: Almost at wits end!!

Until you bite the bullet & get the crud/water out of the main tank you will probably continue to be frustrated. See if you can remove the fuel tank sending unit to your fuel gage. That will give you access to the tank. Then have at it-----------

 

[newellchunker]

Re: Almost at wits end!!

I've done that also, removed the sending unit made a new cover (out of an old planer) used a rag and clothes hanger wire and dabbed all of the old water and as much crud as I could remove out. My access hatch is small. I drained the tank with a Mr.Gasket fuel pump and there wasn't much left in the tank. I was wondering if I could just use the fuel pump to run the fuel to the filters...(& engine)...any suggestions???? I really would like to know what the heck the problem is with this one tank!

 

[mattttt25]

Re: Almost at wits end!!

i'd be looking at the fuel lines, specifically what is the difference between the two tanks. where is the filter located, after the 2-way switch? is so, look back at the fuel lines from the valve to the tanks. something has to be different. is one longer than the other? is one curved more than the other?

 

[newellchunker]

Re: Almost at wits end!!

The main tank's line is probably 3-4 ft. longer. That tank is located under the console and the reserve is located (under the floor also) 2ft. closer to the engine. Both tanks have 3/8 line. The main tanks line is probably less curved.....just longer! Is there a possibility that my engines fuel pump is weak?? and that is the problem?

 

[Solittle]

Re: Almost at wits end!!

If you have access to an electric marine fuel pump you can use it to suck fuel(+crud/water) out and run it through a fuel filter/water seperator and then back into the tank. I think that is basically what the pros do and is called scrubbing the fuel. You will need to dump the filter until the fuel gets clean.<br /><br />I would not give a lot of weight to valves, curve in the tank or diameter of the hose as being part of the problem. If you have crud/water in the fuel it has to come out.

 

[pine island fred]

Re: Almost at wits end!!

That hose should not colapse under suction. You said you had the check valve out. Remove it again and push the finger filter screen out of the pickup tube. Push from the bottom to the top. Operate it without the screen and see if it makes a difference. Amazing how may bugs, leaves somehow make it to the fuel tank. fred