another fuel problem, please help.

« **on:** April 06, 2013, 07:36:43 PM »

just got my boat done and have taken it out twice just for test and tune. The first time I took it out it ran okay for about two small passes then fell on its face. I looked at my clear fuel filter and it was only half full with a bunch of bubbles in it. turn the key of then start it and it might fill up and work just till i got the boat on plane then fall on its face again with a shit load of bubbles in it. took it home and replaces all fuel line with 3/8 id fuel line because i found some cracks in the old. took it out today and it was a little better but punched it would try to fall on its face again with bubbles in fuel filter let of pat the throttle and it would be fine. running a mild 454 with about 40 hours on it, a almost new Holley 4150 carb, electric fuel pump, running about 6 psi. needing some suggestions on what you guys think it might could be. was thinking about replacing the fuel pump but wanted to see if it could be anything else before I spend the jack. Is there screens on the pick up tubes in the tanks? its a 86 kustom kraft with aluminum tanks. any help would be greatly appreciated.

« **Reply #1 on:** April 06, 2013, 08:32:20 PM »

Are you running dual tanks?
Is the t sucking out of both tanks?

Try switching valve to one tank, my boat did the same exact thing now use one or the other and all issues fix. Hope this helps

Chris

« **Reply #2 on:** April 06, 2013, 09:29:19 PM »

Ya I have dual tanks. I only use one at a time already. its driving me crazy cause its the last dam thing I have to fix before its good to go for the summer.

« **Reply #3 on:** April 07, 2013, 04:46:45 AM »

I had a similar issue not too long ago where the motor would idle and run at low rpm's but when I punched it the motor would die. It only occurred on one tank. The issue was the "anti-syphon valve".

« **Reply #4 on:** April 07, 2013, 06:08:25 AM »

Bubbles indicate a sucking air on the suction side of the fuel system, could just be a pin hole or any place it can get air instead of fuel.

« **Reply #5 on:** April 07, 2013, 07:33:23 AM »

Thanks for all the replies. I thought it was sucking air as Well. That's Why I replaced all the fuel line. It doesn't do it all the time either. Seems like it does it only with a load on it. If I turn the key on right now it fills up with no bubbles at all. I have my fuel lines from tanks to ball valves with a tee so I can switch from tank to tank all new, then from ball valve to water fuel separator, water fuel separator to fuel pump, from fuel pump to inline filter and then to regulator.

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« **Reply #6 on:** April 07, 2013, 09:12:57 AM »

Is your Regulator a high flow Or a cheap one from AutoZone. I've had problems with the cheap ones flowing enough fuel on a four cylinder 22r.

« **Reply #7 on:** April 07, 2013, 09:33:41 AM »

check float level, then remove all that shit and go straight from the tank to the pump, then to the regulator, then to carb. no valves, filters or other stuff. just hose... then add one piece at a time until you find the problem. if it does not work the way i laid it out its either the pump, tank (pick up) or the regulator and thats only if the carb is rite

« **Reply #8 on:** April 07, 2013, 11:46:03 AM »

Thanks Ralph I will start on that and post progress. Thanks guys for all the help.

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« **Reply #9 on:** April 07, 2013, 12:57:58 PM »

Those valves are not rated for negative pressure. Follow Ralph on this. What sealant are you using on the pipe threads?

You should be using Gasoila, no Teflon tape. You are either sucking air or vapor locking, the signs are the same.

GT

« **Reply #10 on:** April 07, 2013, 07:30:57 PM »

While I'm at it What is a Good fuel regulator to use? I'm using a cheaper one but it's new and I haven't had any problems yet. I don't want no problems later on though.

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« **Reply #11 on:** April 07, 2013, 07:48:47 PM »

Quote from: j. mayanard on April 07, 2013, 07:33:23 AM

Thanks for all the replies. I thought it was sucking air as Well. That's Why I replaced all the fuel line. It doesn't do it all the time either. Seems like it does it only with a load on it. If I turn the key on right now it fills up with no bubbles at all. I have my fuel lines from tanks to ball valves with a tee so I can switch from tank to tank all new, then from ball valve to water fuel separator, water fuel separator to fuel pump, from fuel pump to inline filter and then to regulator.

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Have you tried draining the water separator? Are you sure your "bubbles" are not water in the fuel?

« **Reply #12 on:** April 07, 2013, 09:15:58 PM »

Almost positive it's not water, it runs to Good to be water. Pretty sure it's them ball valves and shit I have. Going to replace all that.

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« **Reply #13 on:** April 19, 2013, 06:55:03 PM »

Well I replaced the fuel valves with standard marine fuel valves to replace the ball valves I was using. I replaced fuel filter, fuel pump, fuel regulator and still can't get fuel to fill up my fuel filter. I've by passed the water fuel separator and just a little gas, I've by passed the fuel valves all together and the same thing. I can blow easily in to the tank and I can take a longer hose from the tank and siphon fuel. Bang head I'm at a stand still. Anybody have any other suggestions? I have a half a tank of fuel in both tanks, pick ups are in the rear and have even raised the bow of the boat.

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« **Reply #14 on:** April 19, 2013, 07:02:06 PM »

Can you pull the pick ups out and check them out, also try opening the fill caps to the tanks and see If that changes anything. May not be venting

« **Reply #15 on:** April 19, 2013, 07:17:42 PM »

Not enough room to pull pick up tubes all the way out unless I pull tanks out. That's What I'm afraid Im going to have to do. The little I seen of the tube it didn't look bad. I've tried with the caps open and no change. If the tubes where Jacked up would I be able to siphon fuel out of them pretty easy?

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« **Reply #16 on:** April 19, 2013, 07:28:08 PM »

are you sure the pump is good? what brand? the holleys have a little screen in em that tends to get gunked up.

at this point just grab some hose and see if you can move fuel from one tank into a bucket.

ive ran my boat on the trailer from a little gas tank before... if you suspect valves and pickups just run a hose to a little tank and see if you can keep it running. you can get a glimpse of the tank i had mine running on in this video back when i first got my boat and the tanks were filled with horrible HORRIBLE gas. and that was just running a little tiny mr gasket fuel pump...

« **Reply #17 on:** April 19, 2013, 07:58:05 PM »

Sorry guys I'm a jet fuel mechanic I never pipe tape it has some times leaked or sucked air I always use thread sealant with Teflon # 765-1188 item number from napa autoparts it's the best stuff. No leaks or air problems.

« **Reply #18 on:** April 19, 2013, 08:08:01 PM »

Not going to reread the entire thread... What are you trying to accomplish?

If you have not tried it already, did you try priming the pump?

I normally squirt a little Marvel Mystery in a new fuel pump, sort of helps seal it up upon a dry start...

« **Reply #19 on:** April 26, 2013, 08:21:10 PM »

Been working on fuel problem.I have redone everything. Bought all new shit That's for use with fuel. For some reason though I have figured out that if I mount my Carter pump as low as possible it will not prime and keep pumping the fuel. But if I raise it up high it pumps fine. That's been my hole problem. Guess I didn't have pump mounted high enough wich doesn't make sense being everything I have read says to mount as low as possible. I've tried two different Carter pumps and a clone Holly. Any thoughts?

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« **Reply #20 on:** April 26, 2013, 11:39:43 PM »

The fuel bowl will never show full, however the bubbles indicate either air or the lack of fuel. I use a elecrtic pump by the tank and a mechanical at the engine. This stops the drain back of fuel and keeps the fuel prime constant. Also be sure your pumps are the right GPM . Your falling on its face indicates a lean fuel situation and also could be too slow of advance in the distrubutor. Check the total advanve the intial will be what it is, that is what is more important One thing at a time, not a bunch of things you will never know what the fix is that way. Good luck.

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