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My 6.5NH Hates Me -or- It's Always Good To Have A Backup Genset


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  #11  
Old 03-06-2017, 06:29:21 AM
squidtrap squidtrap is offline
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Default Re: My 6.5NH Hates Me -or- It's Always Good To Have A Backup Genset

JohnnyC- my rubber gasket as you show was falling apart around the edges, also if u pull the middle from the pump apart. plunger and spring and check balls on top you will find a small rubber washer, guess its a check valve also, mine was totally BUSTED causing what u show , and no pumping.

I made one from some thin rubber and it works fine, just my .2 cent. Ed.
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  #12  
Old 03-06-2017, 08:11:17 AM
Kevin K Kevin K is offline
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Default Re: My 6.5NH Hates Me -or- It's Always Good To Have A Backup Genset

I have had the rubber gasket on top of the plunger degrade and get into the carburetor as well. That's why I recommend a new fuel pump on any generator you are using for a backup. For about $40, it's not worth taking a chance on an old fuel pump failing just when you need it.
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  #13  
Old 03-06-2017, 12:47:28 PM
geezer88 geezer88 is offline
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Default Re: My 6.5NH Hates Me -or- It's Always Good To Have A Backup Genset

Quote:
Originally Posted by JohnnyC View Post
I don't know where the black flat flakes originally came from or what they were.
JohnnyC
New Jersey
Does the carburetor have a black plastic float? If so, is it possible for the float arm to be bent such that the black plastic is rubbing off by vibrating against the fuel bowl?

tom
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  #14  
Old 03-06-2017, 01:01:15 PM
len k len k is offline
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Default Re: My 6.5NH Hates Me -or- It's Always Good To Have A Backup Genset

3 ideas

1) --- on other small engines I like to replace rubber lines with new, and put an inline filter a few inches before carb. This way any crud in lines/pump/tank that may flake off are trapped in final filter. And flush the new gas lines before closing up carb. I'm done cleaning carbs in cold windy storms.

2) --- May not be the black partials that are causing the gas overflow. On some 70's cars when they started using foam floats they became porous and filled with gas. Throw float in a cup of gas and see if it floats well. Or weigh float then put float in a warm place (130 degs??) to evaporate gas for a week and weight again. After replacement I put the old car foam float in a vice and squished it, gas rained out of it like a wet sponge.

3) --- I just went thru your leaking problem on a Tecumseh carb I rebuilt on a 10 hp snowblower. I assumed float seat was bad and just bought a $4 carb kit with new seat and needle valve. Later I noticed that on the needle the little wire that clipped over float tang was loose on new one and gripped it tight on old one.

Previously I had bent old wire tight to float tang, assuming it would help pull needle out of seat. I guess that may have made it bind. Alternatively could have been an old hard seat , but it didn't seem bad. After installing new seat, needle and, it's wire clip that carb doesn't leak anymore.

Also bore the needle valve went down might have had a tiny speck or 2 of white corrosion on it. I wrapped a good grade of 500 grit sandpaper over a drill and smoothed it out. Up and down strokes so any groove would not grab needle. Used Q-tips in a drill to clean out bottom of bore for seat to seal on.

Last edited by len k; 03-06-2017 at 03:50:37 PM.
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  #15  
Old 03-06-2017, 07:45:44 PM
JohnnyC JohnnyC is offline
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Default Re: My 6.5NH Hates Me -or- It's Always Good To Have A Backup Genset

Thanks for all the comments and suggestions.... Today after work I got busy and did 2 things; 1) open up the carburetor to see what, if anything, is on the bottom of the float bowl, 2) dissect the fuel pump by removing the (for lack of better words) plunger shaft and inspect the rubber components.

1) The carburetor - Keep in mind, I just rebuilt it several days ago by cleaning out all the black crap in the float bowl. This meant disassembling the carburetor, flushing the passages with carburetor cleaner, and blowing everything using compressed air. The carburetor was totally clean and like new.

This evening there was more black crap in the bowls. No way would have I missed the crap while cleaning the carburetor recently. The first 2 pictures attached below show some of the crap found at the bottom of the bowl. There is not as much as before I rebuilt the carburetor, but enough to cause problems. What is this crap???

2) I dissected the fuel pump focusing on its rubber components. Without a doubt, it is shot. Look at the 3rd attached picture below. Those here that are familiar with the pump will easily see the problems, but to make it easy, I marked them out. What remains of the rubber is very brittle.

What puzzles me is some of the crap found at the bottom of the fuel bowl seems too large to fit through the tiny hole in the needle valve seat. Maybe the pressure was enough to force it through?

UPDATE: I found a picture of the same part of the same model pump from my sacrificial 4.0BFA showing the rubber component attached to the end of the plunger (see picture #4 below). It is in very sad condition, but the pump still worked well enough to run the motor.

I will be testing the float which is made of dense hard foam. Stay tunes for the results.

JohnnyC
New Jersey
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Last edited by JohnnyC; 03-06-2017 at 07:59:49 PM.
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  #16  
Old 03-06-2017, 07:53:13 PM
len k len k is offline
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Default Re: My 6.5NH Hates Me -or- It's Always Good To Have A Backup Genset

When they first started using foam floats in ~ 70's in cars they used wrong material and they became porous to gas and sunk. Later they changed either material or coating and problem went away. Your NH may have been made around that time period.

I suspect gas did not have ethanol or MTBE in the 70's, so it likely was direct attack by the couple dozen components in gasoline. When I tired to use silicone rubber to seal an engine 1/2 gal gas tank it swelled up to 10-20 time it's size to a jelly and just about fell off in ~ 10-15 hours. And I had let a thin coating of that silicone rubber cure for several days before hand.

On my snowblower and generac I add one of these style disk filters inches before carb. They came from O'riellys auto parts and have a fine metal screen, ~ $3. https://www.bing.com/images/search?v...x=3&ajaxhist=0

Last edited by len k; 03-06-2017 at 08:08:23 PM.
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  #17  
Old 03-06-2017, 08:07:36 PM
squidtrap squidtrap is offline
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Default Re: My 6.5NH Hates Me -or- It's Always Good To Have A Backup Genset

Thats it, mine was just like that, totally disintegrated. I made a new one with rubber thicker than an inner tube and all was good. Your pick looks a little different but its on top of the plunger and spring.

missed last pick, its the same, mine has been going 2 years now.

Last edited by squidtrap; 03-06-2017 at 08:09:35 PM. Reason: info
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  #18  
Old 03-06-2017, 08:08:13 PM
JohnnyC JohnnyC is offline
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Default Re: My 6.5NH Hates Me -or- It's Always Good To Have A Backup Genset

Len, I am currently testing the float in my toilet. It is a floater (see pictures below).

JohnnyC
New Jersey
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  #19  
Old 03-06-2017, 08:10:19 PM
len k len k is offline
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Default Re: My 6.5NH Hates Me -or- It's Always Good To Have A Backup Genset

Not good enough test, test float it in gas.
Gas is only ~70% the density of water, so it may float in water even if float is full of gas.

An empty glass coke bottle floats in water, but sinks in 5 gal pail of gas.
Child hood spent playing with pails of gas from a car at dad's garage.

Last edited by len k; 03-06-2017 at 08:31:37 PM.
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Old 03-06-2017, 08:19:47 PM
Vanman Vanman is offline
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Default Re: My 6.5NH Hates Me -or- It's Always Good To Have A Backup Genset

RTV silicone is readily attacked by gasoline, in fact that's a very effective way of removing it. Two part epoxy (like JB Weld. Hey, you can use it ON a JB!) withstands gasoline, and evidently ethanol laced crapoline as well, as I have a repair on the fuel tank of my truck that is still holding after ~15 years. The nice people I bought it from were too busy talking about their religion and so *forgot* to mention that the tank leaks like a sieve if you fill it up over half way.
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