New fuel pump didn't fix it...

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rboat99

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I went out this weekend to test the new fuel pump I installed while trying to fix the problem of hesitation/stuttering at WOT. The problem occurs at 5400 RPM and above, where the RPM's will drop 500-1000 RPM and then return, drop then return, etc. Engaging the choke or pumping the primer bulb eliminates the problem temporarily.<br /><br />I bypassed all fuel lines, vents, filters, etc by using a portable gas tank connected directly to the inlet of the fuel pump and still had the problem.<br /><br />One thing I noticed this weekend is that I have a steady drip of fuel coming from the bottom of the carbureter cover (the plastic piece with V4 molded in it). It appeared to be coming from the area where the plastic and metal meet.<br /><br />Could this be where I am losing pressure and would this cause my symptoms?<br /><br />Is there a gasket that I can change that will stop this leak? <br /><br />I also noticed a hose or a wire harness that appears to be hanging out of the bottom, port side of this housing, between the plastic and metal. Is this normal or could that be part of the problem as well?<br /><br />Sorry for the long post...
 
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Walker

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Re: New fuel pump didn't fix it...

A new gasket will not solve that propblem. You need to find where that extra fuel is coming from. Most likely a carb float is set wrong or stuck.
 
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rboat99

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Re: New fuel pump didn't fix it...

So in other words Walker, the fuel would not be leaking there unless it is also leaking from the carburetor? How difficult is it to rebuild these carbs? I've never done it.<br /><br />I should mention that a wrench rebuilt this engine about a year ago, and I think he also rebuilt the carbs.
 
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Brew2

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Re: New fuel pump didn't fix it...

If your 140 is anything like my '86 140...rebuilding the carbs is relatively simple. Just buy the carb kits from a dealer and take your time (take one carb apart at a time so you don't intermingle the parts).<br /><br />You might want to remove the airbox cover (the thing with the "V4" on it, start up the motor on muffs, and have a look and see if you can determine which carb is leaking the gas. You might get away with tapping the float bowl on that carb and releasing a stuck float valve. Note that you do not want to run the boat on water with the air cover off. <br /><br />Good luck!
 
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rboat99

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Re: New fuel pump didn't fix it...

So would a mal-adjusted or stuck float cause the hesitation problem I am having, or does anyone have any other ideas?
 
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Brew2

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Re: New fuel pump didn't fix it...

Carb kits are about $15-$20 per carb. I assume your 140 would have 4 carbs, so you would need 4 kits.<br /><br />A stuck float could cause the problem by flooding one cylinder with gas (is any one spark plug wet?)...could also be any number of other things such as....clogged jet(s) in one or more carbs starving a cylinder for fuel....loose fitting somewhere in your fuel system allowing air in...<br /><br />I'd start by tracking down the source of the fuel leak and going from there. If it is a loose hose, you might get lucky and have a really quick fix.<br /><br />Failing that, I'd remove each carb, clean it thoughly (making sure the jets were not clogged), install carb kits and see what happens.<br /><br />Good luck!
 
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mercerlaw02

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Re: New fuel pump didn't fix it...

Dealing w/ similar problem...I heard that syncronizing the carbs could be difficult. Is that true?
 
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Solittle

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Re: New fuel pump didn't fix it...

The OMC shop manual is a big help for - - - well most any repair.
 
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rboat99

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Re: New fuel pump didn't fix it...

I have a clymer manual. Does the synching have to be done when you do a rebuild, or only if it is needed?<br /><br />The rebuild kit didn't come with much, just a few gaskets, o-rings, and a metal tip of some sort. No instructions, hopefully my clymer manual will get me through it since I have never rebuilt a carb.
 
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Brew2

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Re: New fuel pump didn't fix it...

The Clymer manual should walk you through the carb removal/instalation. That metal tip you see is the needle valve which is inside the float bowl. It will be obvious where it goes once you take the first carb apart. Make sure you set the float level after installing the new needle valve. I'm sure the manual will detail this but...to set the float, adjust the tab the needle valve attaches to until the turn the float is level with the rim of the carb bowl when turned upside down. Again, it will be more obvious once you take apart the first one.<br /><br />A link 'n sync isn't necessary after a carb rebuild...but it isn't a bad idea since it only takes about 1 minute to do. Again, the manual will give a much better description then I ever could.<br /><br />Good luck and keep us posted.<br /><br />Cheers.
 
OBJ

OBJ

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Re: New fuel pump didn't fix it...

rboat....it's very possible that you may have one or more bowls that have warped. This is a common thing with the plastic bowls. When you remove them, put the gasket surface on a flat surface. Warpage will be apparent. You can re-flatten them by working them down on fine grit paper if the warpage is not to severe.<br /><br />Sounds like you got the generic kits. Shoulda' got the OEMs with new floats and all. Well, keep posting what's happening. Let us know if you run into trouble.
 
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rboat99

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Re: New fuel pump didn't fix it...

OBJ, I got the bombadier kit from the johnny/rude dealer. I didn't know what to ask for, I just told him I needed two rebuild kits and gave him my motor specs. Was this not the OEM version?<br /><br />Also, I read another post about the plastic bowls warping and that the replacement bowls were aluminum. Do you know about how much the replacement bowls are?
 
OBJ

OBJ

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Re: New fuel pump didn't fix it...

rboat....you should gotten floats in the kits. I'll check when I get back to the shop and let ya' know.<br /><br />The replacement bowls are plastic on these engines. The two barrel carbs have metal float bowl replacements.
 
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rboat99

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Re: New fuel pump didn't fix it...

OK, I thought I read in my manual that I had two, two-barrel carbs for my engine, but I do not have the book in front of me.<br /><br />Do you know approximate cost either way? I seem to remember a wrench having a problem with one of my carbs leaking and he couldn't figure out why, maybe I just need to sand or replace the bowl.
 
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rboat99

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Re: New fuel pump didn't fix it...

OBJ, I should mention that since I've never worked on a carb I wouldn't know what a float looked like if you smacked me across the face with it. It could be in the kit, I was just noting that the kit didn't seem to have a lot of parts. <br /><br />BTW my Serial Number is 4584991 and my Model Number is 1537LWC (might have these reversed) if it helps you determine what carbs I have.
 
OBJ

OBJ

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Re: New fuel pump didn't fix it...

The float bowl is on the bottom of the carb. It covers the float and holds the gas.<br /><br />Let me give you a couple links to where you can get a OEM service manual for your engine. It would clear much up for you.<br /><br /> http://www.marineengine.com/manuals/johnson/ <br /><br />or<br /><br /> http://ww3.kencook.com/evinrudejohnsonmanuals/ <br /><br />The latest part number for the kits is 439079....around $16 each American.
 
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rboat99

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Re: New fuel pump didn't fix it...

OK, I ordered the service manual. I will check the part #'s on the kits, I ordered 2 and it totalled out at around $35.<br /><br />Thanks everyone! I will keep you posted.
 
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rboat99

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Re: New fuel pump didn't fix it...

I just checked the part number, it is 439079. If the float is a C shaped plastic piece with a metal bracket coming out the side, I got one with each kit.
 
OBJ

OBJ

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Re: New fuel pump didn't fix it...

You got it rboat. Get the manual and a six.....make that a twelve pack of Longnecks and sit down and go through it. They are definetly worth the price.
 
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