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Brison 3.2 Carb Help!! (Where is Ralph when you need him!)

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Brison 3.2 Carb Help!! (Where is Ralph when you need him!)

Old 02-16-2008, 08:30 PM
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Kevin Greene
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Default Brison 3.2 Carb Help!! (Where is Ralph when you need him!)

I'm posting this for a friend----We tried to get his Brison 3.2 going today but we ran into carb trouble....Fuel leaks from the venturi like a broken dam. I took the carb apart to inspect all of the needle passages...The needle and the carb passages were all clean as I could spray carb cleaner through them with ease....

What causes the fuel to drip from the venturi???---Also, I could only get the engine to run at WOT---Anything below half throttle the engine would die....All of the rubber internals looked fine---The only fault that I could find is some trash stopped by the internal carb filter screen....

Additionally---What is a good starting point for the high and low needle settings??? As he received the engine the needles seem to be out of whack as compared to other engines that I have owned...The high was only 3/4 of a turn out and the low was a whopping 3 1/4 turns out---Strange!!!....

My buddy purchased this engine used and it apparently has been sitting for quite a while...However, as previously stated, the inside of the carb was clean and not gummed up...Any help would be appreciated...It sure would be nice if Ralph would chime in!!![sm=thumbs_up.gif][sm=thumbs_up.gif][sm=thumbs_up.gif]

Kevin
Old 02-16-2008, 09:17 PM
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krayzc-RCU
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Default RE: Brison 3.2 Carb Help!! (Where is Ralph when you need him!)

L= 1.5-2.5 out
H=5/8 to 1 out
Old 02-16-2008, 09:19 PM
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Default RE: Brison 3.2 Carb Help!! (Where is Ralph when you need him!)

Ralph is gone. He won't post on this site anymore. []

Sounds to me like the main jet is stuck open. You need to take the 4 screws out of one side and remove the diaphragm. Take the phillips head screw out of the fork (careful not to loose the spring) and remove the jet underneath. Look for sludge or buildup around the shaft of the jet.

Best thing to do is strip the carb and rebuild it. Clean it up with carb cleaner after you have it disassembled. Then rebuild it.

Or, go to Ralphs website:
http://www.rcignitions.com/

He will usually call ya back. Leave him a message.
Old 02-16-2008, 09:37 PM
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Default RE: Brison 3.2 Carb Help!! (Where is Ralph when you need him!)

Metering needle stuck.
Old 02-16-2008, 09:55 PM
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Default RE: Brison 3.2 Carb Help!! (Where is Ralph when you need him!)

Additionally---What is a good starting point for the high and low needle settings??? As he received the engine the needles seem to be out of whack as compared to other engines that I have owned...The high was only 3/4 of a turn out and the low was a whopping 3 1/4 turns out---Strange!!!....
After you get your metering needle taken care of you can get an online manual here. www.rc-revolution.com/docsu.htm Notice there are 2 different factory starting points for the needles. One for engines before 2004 and one for after 2004. Seems they changed carbs in 2004.
Old 02-16-2008, 09:59 PM
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Default RE: Brison 3.2 Carb Help!! (Where is Ralph when you need him!)

I took the metering needle out of the carb---Blew carb cleaner through it and even shot carb cleaner from the inlet nipple through the metering circuit---The needle moves freely---Unless there is some crud around the needle's seat that I can't see, I'm baffled as to why fuel still drips from the carb...

I'll strip 'er down again and see what I come up with---And rebuild it with new parts---Thanks for all of your help!!!

Kevin
Old 02-16-2008, 10:27 PM
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Default RE: Brison 3.2 Carb Help!! (Where is Ralph when you need him!)

Could be gunk that you can't see.

I called it the jet -- metering needle-- sorta the same thing. The metering needle stops the flow of fuel from the jet into the bowl.

Some metering needles that I've seen have a rubber ring sorta built into the tip. I've seen this get clogged with gunk and cause it to not seat. Also seen the seat in the jet get clogged up. That could be the case here. Sometimes when an engine sits for a long time, all the gas will evaporate out of the carb, but the oil is left behind and it gets hard or sludgy.

With fuel flowing out and flooding the engine, that tells me that the pump is not being stopped and it's just forcing fuel into the venturi. That metering needle/spring combo is what stops the pump from overcoming the engine. The pump will move a lot more fuel than the engine can actually use.

I'd rebuild it, as you said. If that don't fix it, just buy a new carb. You can get Walbro carbs pretty reasonable now. Even if it cost ya $40, it's worth it. The hassle isn't worth the $40 if you can't figure it out and make it run good. I had the same problem with a Poulan 54cc engine once. Left it sit around for a couple years and then it wouldn't run right. I rebuilt the carb and fought it for a couple months. Finally got mad and sold it to a guy in Florida. Told him it had carb problems and sold it to him cheap. He just bought a new carb for it. Sent me a video of the engine yanking his Midwest Extra around like a rag doll. Rubbin' it in!! Why didn't I do that? [:@]
Old 02-16-2008, 11:41 PM
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Default RE: Brison 3.2 Carb Help!! (Where is Ralph when you need him!)

Make certain the top groove in the metering needle is in the fork of the lift tab and not under it. The you may need to adjust the needle height. See the manual for the correct height.

Rcpilot has a good point about left over oil, and the cost of carbs. It has caused a lot of grief at times. If the carb is dripping fuel the root cause is somewhere around that metering needle.
Old 02-17-2008, 08:30 AM
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Default RE: Brison 3.2 Carb Help!! (Where is Ralph when you need him!)

Ditto both RCpilot and Roy.

If possible, use a pressure tester (pop-off tester) or pressurize the fuel line. If the main metering needle seats well, there will be no fuel leaks with the fuel supply line under pressure. If it does leak with the regulating membrane removed, the fuel needle and/or stuck fulcrum lever and/or fulcrum lever spring can be the only culprits.
With a micrometer depth hauge check fulcrum lever height. Too high a lever setting will leak fuel all the time. In most carbs, it should be equal to the surrounding casting, or the carb body with membrane gasket in place.
Old 02-17-2008, 10:19 AM
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Default RE: Brison 3.2 Carb Help!! (Where is Ralph when you need him!)

The fuel tank is a little higher than the carb so the fuel is just siphoning into the carb and dripping out of the venturi---When I took the carb apart I made sure that the needle was seated into the fork and it could be easily moved up and down....

I'm pretty mechanically inclined as I can tear an automobile apart and put it back together blindfolded as I used to restore cars---Including tearing down some pretty intricate Weber carbs...I'll tear apart the carb again and take a look at the seat area and clean/blow her out....If this doesn't fix it then I'm suggesting that my buddy get a new carb..

Kevin

PS---I think that the carb is a WT 76A
Old 02-17-2008, 10:54 AM
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Default RE: Brison 3.2 Carb Help!! (Where is Ralph when you need him!)

PS---I think that the carb is a WT 76A
so correct
Old 02-17-2008, 11:10 AM
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Default RE: Brison 3.2 Carb Help!! (Where is Ralph when you need him!)

My 3.2 ran so much better after installing a carb rebuild kit. The pump and metering diaphragms can get old/brittle, gaskets can leak, needle can not seat. The carb kit I bought from my local chain saw repair shop was part number K20-WAT. You will find there are some extra parts, but if you replace all the soft goods, you'll be miles ahead. It's pretty simple; just take it apart and replace everything with new parts on the way back together.
Old 02-17-2008, 11:35 AM
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Default RE: Brison 3.2 Carb Help!! (Where is Ralph when you need him!)

u r so right a rebuild kit to a carb every now and then makes the motor just sing.....
Old 02-17-2008, 04:48 PM
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Default RE: Brison 3.2 Carb Help!! (Where is Ralph when you need him!)


ORIGINAL: Kevin Greene

The fuel tank is a little higher than the carb so the fuel is just siphoning into the carb and dripping out of the venturi---When I took the carb apart I made sure that the needle was seated into the fork and it could be easily moved up and down....

I'm pretty mechanically inclined as I can tear an automobile apart and put it back together blindfolded as I used to restore cars---Including tearing down some pretty intricate Weber carbs...I'll tear apart the carb again and take a look at the seat area and clean/blow her out....If this doesn't fix it then I'm suggesting that my buddy get a new carb..

Kevin

PS---I think that the carb is a WT 76A
Definately a non seating metering needle. Take off your blindfold , check the parts and see if you need a rebuild kit.
Telltale is a non-flabby metering diaphragm. With flabby, I mean real flabby. Any stiffnes in that part indicates the need for a rebuilt.
Old 02-18-2008, 12:45 AM
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Default RE: Brison 3.2 Carb Help!! (Where is Ralph when you need him!)

Pe,

Thank you so very much. I deleted the entire post I had in reply to his last before posting. You handled much more politely than I was going to

BTW, Thanks again for all that oil info. I'll send a follow up via e-mail.

Pat
Old 02-18-2008, 12:34 PM
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Default RE: Brison 3.2 Carb Help!! (Where is Ralph when you need him!)

Thanks for all of your help fellas---I found brand new WT 76A carbs on Ebay for $12.99 + $3.99 shipping....My buddy has one coming!!!

Kevin
Old 02-18-2008, 02:22 PM
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Default RE: Brison 3.2 Carb Help!! (Where is Ralph when you need him!)

good deal
Old 02-18-2008, 03:28 PM
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Default RE: Brison 3.2 Carb Help!! (Where is Ralph when you need him!)

Thanks for all of your help fellas---I found brand new WT 76A carbs on Ebay for $12.99 + $3.99 shipping....My buddy has one coming!!!
That sounds like a great deal on those carbs. I could use 3 or 4 of them for spares! ..... Thanks for the heads up Kevin, I just ordered a couple of them. Now there are only 11 left!

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