My needle problem?

[Mike Hughes]

So in the past couple outings with my 12 hydro I have had needle issues. First was I could not get a consistant needle. It kept changing because the needle was flowing so little that if you bumped it, it changed. This was an OS needle that I have used for years and works great if you are flowing more. So I bought a bunch of others to try and get something flowing correctly.

I also got my tank from Walt. So in with the new tank and needles and headed to a race. Would figure it out there. Well, needless to say that did not go well. I spent the day setting my needles at one setting with them coming back with a setting no where near what it was when it left the beach. I tried all 3 new needles that I bought and all had same issue. Boat would go out, go way to lean and over heat, usually taking the plug. Needles were not the problem. PLUS I GOT TIRED OF ROWING. So came home all pissed off and let it sit for a week. I figure I would try and test it on the bench at home. Where no rowing would be involved.

My back liked that option.

So took my new tank and hook up the needle. Used the fuel jug pump to fill the vent tube and have the needle just feed the fuel back into the jug. Preset the needle to a setting and started slowly pumping. I pumped enough to simulate about half a race (which was all I was able to do at the race). Low and behold, the needle had jump up 20 points on the boris. Which was less than it had done at the race site. But I could recrete the issue. Perfect. Tried all needles with all the same results.

So now I figure lets go back to the tank I was running earlier (21 hydro tank) and give it a try. Problem went away..........BINGO.

So now the question is what could be on the inside that is causing this. Some kind of coating on the SS sheeting from the manufacture is all I can think of. Its probably not an issue with needles that run high flows because it does not build up. So Im letting tank sit full over night with WD40 in it and see if that will clean it out.

Anyone seen anything similar?

 

[dwilfong]

had a piece of crap in one of my tanks from Walt also.

It was some cotton thy use to clean the tubes out with from manufacturing them I was told.

 

[Mike Hughes]

Im about to give up. Now both tanks do it. Changed fuel, needles, tanks how the hell Im I suppose to fix a problem I cant identify. Stupid boat.

 

[Walt Barney]

Im about to give up. Now both tanks do it. Changed fuel, needles, tanks how the hell Im I suppose to fix a problem I cant identify. Stupid boat.

Mike ,

check your fuel filters and filter in your fuel jug, sound like trash in your fuel system, and now into the tanks, If sill a problem send me both tanks and I will check them out,

thanks

Walt Barney

 

[Rene Danner]

So it is a remote needle or fixed needle. If fixed could it be vibration or if remote could it be the servo not staying centered. Not sure..

 

[Terry Keeley]

Was gonna say I doubt it was the tanks.

What does the needle go in to? Directly into the carb? Ferrette type base? I see you tried 3 new needles but I bet it's in the housing that holds it.

I've noticed the hole where the needle seats inside the Violett units opens up and gets oval shaped after some use, I think it's caused by the needle vibrating in the seat and wearing it out. They don't hold a consistent setting after that.

I'm thinking about designing a unit that prevents the needle from touching the seat even under heavy vibration...

 

[Mike Hughes]

I have a couple of different OS needles, a traxxas, plus the needle on the KB black carb. All are brand new except the black carb. I thought vibration too. Thats why I bench tested. Its not that. All that is being done is fuel run thru them. They get flowed with a wet needle and then fuel run thru them by pressure in the vent tube of the tank. About 4-5 oz thru them and then back to the flow meter. It will flow 10 or more different from the starting point. These are all fixed needles. All with the same results. Moved on to other things now. Working on one of my gliders. That one is fixed.

Got something done today at least.

 

[Mike Hughes]

Fuel filter is clean BTW. Also cant find anything on the needles after they are removed.

 

[Terry Keeley]

I have a couple of different OS needles, a traxxas, plus the needle on the KB black carb. All are brand new except the black carb. I thought vibration too. Thats why I bench tested. Its not that. All that is being done is fuel run thru them. They get flowed with a wet needle and then fuel run thru them by pressure in the vent tube of the tank. About 4-5 oz thru them and then back to the flow meter. It will flow 10 or more different from the starting point. These are all fixed needles. All with the same results. Moved on to other things now. Working on one of my gliders. That one is fixed.

Got something done today at least.

Don't think you're "seeing" what I'm talking about. If the seat is oval if the needle ends up slightly to one side or the other the flow will change...

 

[KenOlvis]

If you tried different tanks needles like Terry says use a different fuel block or carb then try different fuel lines may have a pin hole.the pin hole would change as pressure from pipe increase

 

[John Knight]

Mike,

I agree with Ken, change all of the fuel and pressure lines.

I run 4 fuel filters on my fueling system. Have a ceramic filter in the bottom of the jug, one before the fuel pump and 2 after the pump going into the tank. They get cleaned out at the end of the day along with the pump. Been doing this for over 12 years and I have no fuel issues, unless they are with the fuel and pressure lines in the boat. A flow meter can help chase them down.

 

[David Santistevan]

Bearings? I have chased needles when the bearings were bad. Given you had two engines with the issue you may have gotten a batch of fuel that didn't have the proper lubricants and eventually took the bearings in both engines.

D

 

[SayMikey]

Post a pic of your needles,some OS needles need a piece of fuel line to stop sucking air and hold setting

 

[coolhotrods]

Mike, Since your bench testing everything... Have you tried to fill the tank up at different levels and then tried to flow it. Maybe there's a crack in one of the tubes inside. When the fuel level comes down

it starts getting air... Just an idea. Dustin

 

[Mike Hughes]

Nope not that Dustin. I am removing the the needle from the tank to flow it thru the meter. It acts as if the it getting clogged. But I cant figure out from what. I might go work on it some more today.

Mikey that would be good only if Im running the boat. When you put it on the meter it will flow more if it leaking.

Remember guys Im doing this all on the bench. My back hurts too much from rowing. Did that a couple of weeks ago.

 

[Mike Hughes]

Ok heres a question.......Does anybody know what is the dimension between screen meshing that we normally run in our filters?

 

[Mike Hughes]

Needles

http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXCR44

http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXCU32

http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXJL93

 

[moparbarn]

Mike, I don't know the mesh/micron size on the screen filters. I stopped using them when I found a rc car filter by Patriot RC that uses a MUCH finer nylon/plastic filter element. The filter element is long & tubular, closed at one end, much like the clear screw together full scale aftermarket cleanable filters for autos. I found them at my local Hobbytown USA. Patriot makes a version that uses the usual screen disc also, be sure which one you get. They look VERY similar from the outside, you want the one with the knurled body, not smooth (-;

 

[Mike Hughes]

I did some math and it turns out the the space between my needle and the orifice is about .001" Human hair is about 3/4 that size. Wont take much to clog that. Im thinking of going the jet route. I almost ran a jet the last time I had the boat out. But the jet size that Brian Buaas had for his water was too big to get the flow number.

 

[Terry Keeley]

I did some math and it turns out the the space between my needle and the orifice is about .001" Human hair is about 3/4 that size. Wont take much to clog that. Im thinking of going the jet route. I almost ran a jet the last time I had the boat out. But the jet size that Brian Buaas had for his water was too big to get the flow number.

I see, so you're starting with whole new assemblies.

Looks like they're just not fine enough for your .12's.