Replacing 120 Looper VRO fuel pump

islandkids

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Nov 13, 2004
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I own an old 17' Aquasport with a 1987 Johnson 120 V4 Looper on back. Model # J120TLCUR. It's my first boat and I've had it about a year and a half. I've got the OMC service manual and parts catalog. About six months ago, a local mechanic cleaned and rebuilt the carbs, replaced the impeller, etc. in lower unit, and disconnected and trashed my VRO oil tank. Since then I've replaced all fuel line between the tank and the carbs, new OMC primer bulb, new inline fuel filter, new diaphrams on both sides of the fuel pump. The intake hose that was connected to the oiler is plugged and clamped, and the electrical to it is disconnected.<br /><br />My problem is an air leak in the fuel system somewhere, and I think it's the old fuel pump. She runs fine at a dead idle(800), and she screams on plane (2000-4500), but at 5 knots(1100) it coughs every 30 sec. and I can see an air bubble start to form in the inline filter. If I pump the primer bulb back up I can idle along for miles, as long as I pump the bulb every couple o minutes.<br /><br />Which non VRO fuel pump replaces my VRO disabled fuel pump?
 

rickdb1boat

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Jan 23, 2002
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11,195
Re: Replacing 120 Looper VRO fuel pump

Have you checked the pick-up assembly in the fuel tank? Otherwise,<br /><br />VRO PUMP REPLACEMENT NO OIL MIXING SIDE. 438402 Price:$165.00<br /><br />Found here:<br /><br /> web page
 

islandkids

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Nov 13, 2004
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Re: Replacing 120 Looper VRO fuel pump

Thanks for the info, Rick...I'll price it at my local Johnrude dealer as well <br /><br />Unfortunately, I haven't seen the pickup. The previous owner has the intake tube epoxied to the top of the tank. I'm hesitant to twist it loose, cuz I'll probly break it. I didn't discover an antisiphon valve when I was replacing fuel line, so I installed one. I later removed it because it restricted flow to much...this could also be due to the faulty fuel pump..
 

tashasdaddy

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Nov 11, 2005
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Re: Replacing 120 Looper VRO fuel pump

might it be an epoxyed pickup tube? it's been epxoyed for some reason.
 

DHPMARINE

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Dec 16, 2003
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Re: Replacing 120 Looper VRO fuel pump

If the air bubble is in the inline fuel filter,I would guess the air leak is before the pump.<br /><br />DHP
 

islandkids

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Nov 13, 2004
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Re: Replacing 120 Looper VRO fuel pump

well DHP,if I pump up the primer bulb, the air bubble almost disappears. Do you think I should reinstall the antisiphon valve...It seemed to struggle for fuel and run a bit slower at high rpms with it in...<br /><br />...also, I've been checking posts this afternoon and I noticed a few references between rough idling and thermostats...since my vernatherms aren't in...<br />...it seems that most other fuel pump related posts reported problems with high rpms, but my boat runs great above 1500 rpms <br /><br />also, a note to tashasdaddy... there have been a lot of things which I have "discovered" on this boat that appear to have been done for "some reason", and yet defy explanation :)
 

DHPMARINE

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Re: Replacing 120 Looper VRO fuel pump

islandkids,<br /><br />I think it is time to investigate the "epoxy" on the top of your tank.<br /><br />Other posts have lots of good ideas on a lot of things.<br /><br />Don't forget to focus,and keep up with your posts.<br />(for example a missing veratherm won't cause air bubbles in your fuel line )Don't even go there.Fix this problem first.<br /><br />DHP
 

Goldfish

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Mar 21, 2005
Messages
50
Re: Replacing 120 Looper VRO fuel pump

In response to rickdb1boat, I would not purchase that, I would get a straight fuel pump, a high performance one at that :D If you decide to replace it, (you can actually rebuild these if they ever do fail, and they are made out of metal, not plastic that deteriorates and cracks.)<br />A local OMC dealer got me a P/N 438559 and it works awesome. BUT, I would first check out that tank connection as dhpmarine suggests.
 

Dhadley

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Feb 4, 2001
Messages
16,978
Re: Replacing 120 Looper VRO fuel pump

Goldfish, just be aware that that pump you refer to is a standard old style fuel pump. If you use it on a V4 looper you need 2 of them to supply enough fuel. Just like on a V6 crossflow. Those are good pumps but there's nothing hi-performance about it. In fact at high rpm's it wont pump as much as a VRO or an OMS pump.
 

islandkids

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Nov 13, 2004
Messages
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Re: Replacing 120 Looper VRO fuel pump

DHP, the epoxied intake tube isn't a standard intake. It appears to be a fuel line connection from a car that was rigged for this 25 gal. inboard tank. I had to use a 6"piece of 7/16 fuel line to adapt the intake to a brass connect that necks it down to 3/8. <br /><br />Is it worth it to try and break out the old intake, or should I just start looking for a new tank?<br /><br />My apologies for losing focus on my last post.<br /><br />Dhadley, if I purchase the VRO PUMP REPLACEMENT NO OIL MIXING SIDE. 438402, will it perform as well as the original setup did?
 

rickdb1boat

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Jan 23, 2002
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11,195
Re: Replacing 120 Looper VRO fuel pump

The 438402 will work as a single replacement for your pump. As for the intake in the tank, I believe you are going to have to try and get it out and then replace the pick-up, if possible, or if that fails, replace the tank.
 
Joined
Jan 27, 2006
Messages
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Re: Replacing 120 Looper VRO fuel pump

I think you should get a new tank and start over. That old tank has probably got a bit of water and crud built up in it. Most of them generally do. At least this way you can eliminate the tank thing. Hope it all comes together for you.<br /><br />Bdady :)
 
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