# Rubber tipped needle



## nbpt100 (Jun 1, 2015)

I am rebuilding a Walbro WT-419 carb and the needle in there has a rubber tip. I assume this may be original but I don't know. It looks like it is an orange silicone rubber. The replacement in the Walbro kit K10 WAT has a solid steel tip. My question is should I replace the rubber tipped needle with the solid steel needle. Even if the rubber still looks like it is in good condition. My understanding is the seat is not replaceable unlike other carbs that have a rubber or o-ring seat for the needle to seal against.

Can someone with some experience on this please advise? Thanks!


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## geogrubb (Jul 28, 2006)

nbpt100 said:


> I am rebuilding a Walbro WT-419 carb and the needle in there has a rubber tip. I assume this may be original but I don't know. It looks like it is an orange silicone rubber. The replacement in the Walbro kit K10 WAT has a solid steel tip. My question is should I replace the rubber tipped needle with the solid steel needle. Even if the rubber still looks like it is in good condition. My understanding is the seat is not replaceable unlike other carbs that have a rubber or o-ring seat for the needle to seal against.
> 
> Can someone with some experience on this please advise? Thanks!


Usually the rubber tipped needles are for metal seat, the all metal needles are for non-metal seats. Have a good one. Geo


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## nbpt100 (Jun 1, 2015)

Thank you Geo. That makes perfect sense and that was my gut feeling but I just like to get confirmation from someone who has been there a few times.


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## 30yearTech (Sep 14, 2006)

The needle may look like metal but it's not. The tip should not be orange, it should be black as they have a graphite type coating to help them seal and prevent them from sticking. They kind of look like they are metal, but if you apply a little pressure on them, you can see them distort, if they are solid they will not move.

The K10 WAT kit does not include a solid tipped needle.


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## nbpt100 (Jun 1, 2015)

The rubber tip did have a bit of greyish gunk on it. It only was on about 30% of it. I cleaned it off thinking it was build up of junk. I now assume I should not have done so. Does this mean the needle will now stick? Can I get some of that graphite paste somewhere and apply some? 

My K10 WAT did not have a rubber tipped needle. Are you suggesting that needle in the kit will work in my carb? It looked metal(shinny silver color) but maybe it is plastic. I will take a closer look at it tomorrow. 
Thank you 30 year tech.


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## 30yearTech (Sep 14, 2006)

When I said the needle may look like metal but it's not, I was referring to the tip. The rest of the needle is in fact metal.

The only needle that comes in a K10-WAT kit has a soft coated tipped needle. I don't know how they coat the needles, but when the coating is gone, they have a tendency to stick and leak.

I have included some pictures to illustrate what I am talking about. I grabbed a kit from my service trailer and took the following pictures. In the last image, I applied a little pressure to the needle so you can see the tip distort, it looks solid, but it's not.

K10_kit.jpg
NeedleK10.jpg
Needle_Tip.jpg


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## nbpt100 (Jun 1, 2015)

I just looked at my Walbro kit and I now know what you mean. It is not obvious at first glance. Thanks! I will use the new pin.

What is you opinion or removing the welch plugs on this carb? I saw several YouTube videos and not one person suggested removing them. One person went as far as saying they don't need to be removed and are not used as they are blocking off unused passages.

My experience is with 4 cycle carbs and I know they should be removed to do a complete and thorough rebuild.

What is you experience on this? 
I Humbly admit I am still learning this facet of small engines. Thanks.


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## 30yearTech (Sep 14, 2006)

nbpt100 said:


> I just looked at my Walbro kit and I now know what you mean. It is not obvious at first glance. Thanks! I will use the new pin.
> 
> What is you opinion or removing the welch plugs on this carb? I saw several YouTube videos and not one person suggested removing them. One person went as far as saying they don't need to be removed and are not used as they are blocking off unused passages.
> 
> ...


Well first off they ARE NOT covering unused ports. However, unless I am having an issue with the ports they are covering, I do not remove them. 

You can test flow by removing the adjustment screw and using spray carburetor or brake parts cleaner to spray through the ports and see if they are open. If no flow through them, then I will take them out. If your familiar with their removal, go ahead and take them out, the kit comes with new ones.


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## nbpt100 (Jun 1, 2015)

Thanks. I have no issues with removing/installing Welch plugs. I did see that Walbro no longer recommends using nail polish to seal them off. Apparently the ethanol in the fuel breaks down the nail polish and it causes more issues than it is worth.

You do bring up another point I recently was made aware in a repair video. It said some manufacturers are no longer recommending the use of Carb cleaner because it can break down some of the rubber parts that are not serviceable in the carbs. Instead, they recommend using break cleaner.
I think Echo (I may be wrong so don't quote me) was mentioned as one and I don't recall the others mentioned. While on this topic he also said don't poke wires in the small ports as some have check valves that you can damage and then ruin the carb.

Can you comment on these points?

Thanks 30 Year Tech!


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## 30yearTech (Sep 14, 2006)

All good points and not just for Echo as most all small units use carburetors made by one of the major manufacturers such as Walbro, Zama, Tillotson, Nikki, etc.... 

I still use carburetor cleaner spray but mostly for float type carburetors and usually only when I have to clean out old fuel varnish and build up. Brake cleaner does a great job for most and doesn't leave a film, but even enough of it can swell up rubber parts. Brake cleaner has a hard time on old gas varnish, so carburetor cleaner works better for that.

If I run across a badly varnished diaphragm carburetor, I don't even bother trying to make it work anymore. I just replace them.


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