70's 17' fuel tank

[bwguardian]

I have a 1979 Mako 182...the Backcountry...that is basically a classic 17' they cut the sides down, decked for multiple storage, and added sponsons out back. I am having a fuel related issue that I have a question but I have done the following with the resto rebuild...new 3/8" fuel line from tank to outboard, new fuel filler hose, etc. The motor starves for fuel above 3,000 rpms and when it does the primer bulb goes flat as in under suction from motor and tank not letting fuel in the system. Thinking it was the fuel water separator filter I did replace it twice as of now with 10 hours on the rig. The tank was cleaned prior to getting things buckled up and the first filter showed a little red grit in it so I figured it was just some stuff I could not get.

The only thing I can think of is either a pickup screen getting something lodged in it...but wouldn't think there would be anything left in there to do so...or an anti-siphon valve not doing what it's suppose to. I did pull the fuel hose at the filter and blew back with no issues early on...could hear air bubbling in the fuel tank.

So, does anyone know if these old classic 17's had an anti-siphon valve in the fuel pickup in the tank...or a pickup screen for that matter?

[81Mako235]

Tank vent line clear?

[bwguardian]

quote:

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Originally posted by 81Mako235


Tank vent line clear?

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Yes, when it started happening again yesterday I even loosened the gas cap for added just in case...made no difference.

[Dogman18]

What engine do you have on it? There is ,on some, a filter on the engine itself ? that might be the problem? Have you run a line directly from the tank to the engine cutting out the filter? Replace the bulb?

[bwguardian]

quote:

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Originally posted by Dogman18


What engine do you have on it? There is ,on some, a filter on the engine itself ? that might be the problem? Have you run a line directly from the tank to the engine cutting out the filter? Replace the bulb?

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It is a Mercury 115 ELPTO...carb 2 stroke. The fuel primer bulb is between the motor and the fuel water separator filter so I don't think the engine filter is clogged...I even checked that recently. As noted in my original post the fuel primer bulb was new but I went ahead and put another new one on when these issues started up again. I have replaced the filter twice now...third Quicksilver filter...with only 9 hours on the clock.

This is why I am asking about the anti-siphon valve and or fuel pickup screen.

[Justin]

believe they did have an anti-siphon valve yes

run off a portable tank see what she does

[bwguardian]

quote:

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Originally posted by Justin


believe they did have an anti-siphon valve yes

run off a portable tank see what she does

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Thank you, I just got off the phone with Florida Marine Tanks, and they stated the tank should have an anti-siphon valve and a pickup screen. The anti-siphon valve should be screwed onto the L pickup tube. However, the pickup tube is welded into the tank, and not the threaded removable type. I will pull the deck panel and take a look.

[cgmiller]

Did you replace the primer ball? That is a common issue. They go bad after a while and collapse under vacuum and restrict fuel flow. What year is the engine? You might have an issue with the ethanol deteriorating the interior of the fuel lines on the engine.

[bwguardian]

quote:

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Originally posted by cgmiller


Did you replace the primer ball? That is a common issue. They go bad after a while and collapse under vacuum and restrict fuel flow. What year is the engine? You might have an issue with the ethanol deteriorating the interior of the fuel lines on the engine.

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Yes, as stated in the op went through 2 new ones within 9 hours on motor.

[bwguardian]

I believe the problem has been found. I pulled the deck access to the tank and unscrewed the fuel pickup barb. There was stands of cloth in there that was stuck from the rag I utilized to clean the tank. I would post a picture but not sure how.

Btw, there was no anti-siphon valve and it appeared there was no pickup screen. As added precaution I blew the new 3/8" fuel line from the tank to between the fuel primer bulb and water separator filter to make sure nothing was lodged in there.

I will run the boat within a week so we shall see...

[ssfishx]

most anti-siphon valves are built into the fuel barb at the tank

https://www.westmarine.com/buy/west-marine--fuel-barb-p-h-anti-siphon-1-4npt--13854898?mrkgcl=481&mrkgadid=3138550908&cm_mmc=PS-_-Google-_-GSC%2520-%2520Product%2520Type-_-13854898&product_id=13854898&adpos=1o1&creative=108421551724&device=c&matchtype=&network=g&gclid=EAIaIQobChMI7IKkvbL12wIVDKtpCh0wQwgqEAQYASABEgLrtvD_BwE

even the tiny-est bit of debris will cause the valve to close at least partially

[bwguardian]

quote:

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Originally posted by ssfishx


most anti-siphon valves are built into the fuel barb at the tank

https://www.westmarine.com/buy/west-marine--fuel-barb-p-h-anti-siphon-1-4npt--13854898?mrkgcl=481&mrkgadid=3138550908&cm_mmc=PS-_-Google-_-GSC%2520-%2520Product%2520Type-_-13854898&product_id=13854898&adpos=1o1&creative=108421551724&device=c&matchtype=&network=g&gclid=EAIaIQobChMI7IKkvbL12wIVDKtpCh0wQwgqEAQYASABEgLrtvD_BwE

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Yep and I think someone may have gutted it...aluminum hose barb into brass fitting into aluminum tank.

[ssfishx]

yikes! get rid of the brass fitting, just begging for dissimilar metal corrosion. should be all aluminum for aluminum tank

[bwguardian]

quote:

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Originally posted by ssfishx


yikes! get rid of the brass fitting, just begging for dissimilar metal corrosion. should be all aluminum for aluminum tank

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I looked at it and thought the same...however, after all these years the only thing that showed signs of wear was the hose barb that screws into it on the motor side. My only guess is that the wire grounding the tank helped the tank side as everything looked good there. A little puzzled how that pickup tube is installed as the brass fitting just screws into the tank pickup.