Fun, Learning, Friendship and Mutual Respect START  HERE


Unregistered
Go Back   HeliFreak > R/C Helicopter Support > Gasser Helicopters


Gasser Helicopters Gasser Specific Discussion


Like Tree7Likes
  • 1 Post By rbort
  • 1 Post By fastflyer20
  • 1 Post By GREYEAGLE
  • 1 Post By macdad
  • 2 Post By Dawiev
  • 1 Post By Tnjet
Reply
 
LinkBack Thread Tools Display Modes
Old 09-15-2018, 01:59 PM   #1 (permalink)
Registered Users
 
Posts: 2,505
 

Join Date: Apr 2007
Location: Kent coast, UK
Default what do these symptoms mean?

Had a strange thing that I have not encountered before so I'll describe the symptoms and see if this is something quickly recognisable:

Hanson 300 with TRM pipe - has run perfectly so far. I had not flown it since sometime last autumn so a few weeks ago I took it outside put in a little fuel and it started right away, idles fine and revved OK (without blades). I only ran it for maybe a minute, just to make sure it wasn't going to give me any trouble when I go to the field.

So today I was at the field and expected it to start and run as always. But here's what it did:

First of all it took many pulls and then it finally started but oddly my TX trim was way high and my TH switch was also at much higher revs than it had been - no idea why.

Anyway, although it would idle it seemed to struggle a bit and if I raised the throttle it would start to bog and die, lowering the throttle would let it recover. I let it idle until it was well warmed up but it would never run at higher revs. The pipe was not full of fuel or anything like that, choke off etc.

So I took it back to the pits and pulled the plug and it was pretty much normal. Started it again without blades and it seemed better, it would rev just fine (obviously no load though), but then I realised that my lowest trim on the TX would not shut the engine off! Now that could be a coincidence but it would be pretty strange.

I got it stopped and had a look at my throttle travels and then it would not start again.

So I gave up at that point.

I have taken the carb off and I have to say, what a weird bit of sorcery is going on inside that thing!

Anyway, I can buy a new one (WT 990) which I should have done already as a spare. But if I get a new one I'd hate to think the old one becomes a paperweight, surely there's a part that is likely culprit that can be replaced?
__________________
2009 TDR, Kasama Dune and Faifa, Minicopter Triabolo 700, RMJ Raptor gasser,
Beam E4 and Avantgarde, JR E8 leggero, Suzi Laos, Shape S8, Compass Knight 3D, Robbe Futura SE and Dyna-X, Trex 500.
trillian is online now        Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Old 09-15-2018, 03:49 PM   #2 (permalink)
Registered Users
 
Posts: 4,307
 

Join Date: Feb 2005
Location: Franklin, MA - USA
Default Try to open and close the low needle

Start the engine. While idling close the L Needle 1/4 turn then quickly open it 1/2 turn then quickly go back to the original setting (close 1/4 turn).

Sometimes this will dislodge some buildup around the needle and correct some issue that seems to show the carb is lean.

-=>Raja.
trillian likes this.
__________________
MA 1005, Hanson 280, 4225 flights, Spectra-g, Hanson 270, 3322 flights
Whiplash-g V1-2, Hanson 300, 1633 flights, Whiplash-g V2, Hanson 300, 497 flights
Jewel on-board Generators, Miniature Aircraft Team Manager
rbort is offline        Reply With Quote Quick reply to this message
Old 09-15-2018, 08:22 PM   #3 (permalink)
Registered Users
 
Posts: 4,834
 

Join Date: Nov 2008
Location: Buffalo Area
Default

You can buy a carb rebuild kit for the 990, Walbro part number K10-WAT. It's always worth a shot, however there are some small passages that do not always cooperate. I would buy 1 new carb and a few rebuild kits. The kits include new diaphragms that can get brittle with age. A full rebuild includes removing the soft plug for access to some passages, the kit has a new plug. I install the new plug then drizzle JB weld on the edges to insure its sealed.
trillian likes this.
__________________
Tom

TRM Power
CAUTION - my posts are based on my experiences, yours may be different.
fastflyer20 is offline        Reply With Quote Quick reply to this message
Old 09-15-2018, 08:26 PM   #4 (permalink)
Registered Users
 

Join Date: Jul 2006
Location: Flat Lands
Thumbs up Your fuel flow metering needle is glopped up. > Normal

These are pulse driven diaphragm carbs off the crankcase.

Under the cover on one side is a fuel metering needle that is inserted into the main-fuel circuit.

They hang up after sitting for periods of time and the circuit dries out. Stick

The tip can be a soft material like viton /the seat it's in contact with can be a hard plastic material.

Running synthetic lubricants - they are notorious for it. They actually are to be very loose in the bore so be careful - around compressed air -.

Lot of times getting them soaking wet and waiting / then tapping on the carbi with a screw driver at the field will do it.

Long as your opening it - clean the internal filter screen.
Leave the needles alone

G.E> Copy write

Your welcome!
trillian likes this.

Last edited by GREYEAGLE; 09-15-2018 at 08:29 PM.. Reason: Googeld it - Google Know's :A.I. is GOOD! > Drizzel It
GREYEAGLE is offline        Reply With Quote Quick reply to this message
Old 09-16-2018, 04:44 PM   #5 (permalink)
Registered Users
 
Posts: 3,183
 

Join Date: Jan 2014
Location: North Baltimore, OH
Default

Sounds similar to the issues I had with mine. For me, the passage between the two sides of the carb was plugged. Some white fuzzies got through the screen. It was not able to get enough fuel to handle any kind of load, but it would idle fine.
trillian likes this.
__________________
Oxy 2, Gaui X3 #1, Protos 380, Gaui X5, Synergy 766 Gasser, Assault 700
Oxy 2/X3/Protos 380/X5/766 Gas/Assault700 Consecutive Successful Flights (Current) = 30/5/56/141/6/70
Consecutive Successful Flights (Max) = 141
macdad is offline        Reply With Quote Quick reply to this message
Old 10-14-2018, 11:20 AM   #6 (permalink)
Registered Users
 
Posts: 2,505
Thread Starter Thread Starter
 

Join Date: Apr 2007
Location: Kent coast, UK
Default

Quote:
Originally Posted by macdad View Post
Sounds similar to the issues I had with mine. For me, the passage between the two sides of the carb was plugged. Some white fuzzies got through the screen. It was not able to get enough fuel to handle any kind of load, but it would idle fine.
The thing I found strange with mine is that the idle was very high compared to the previous time it had been run - I mean much higher, to where I had to go in and change the throttle trims to get it back down to an idle that would not start dragging on the clutch. So something definitely went wonky inside the carb.

For the moment I have put a 643 carb on it that was on my old 260 PUH. I was going to try to start it today but it started raining. I also replaced the fuel tubing and the fuel tank bung so all of that is a lot more secure now as well.
__________________
2009 TDR, Kasama Dune and Faifa, Minicopter Triabolo 700, RMJ Raptor gasser,
Beam E4 and Avantgarde, JR E8 leggero, Suzi Laos, Shape S8, Compass Knight 3D, Robbe Futura SE and Dyna-X, Trex 500.
trillian is online now        Reply With Quote Quick reply to this message
Old 10-14-2018, 10:46 PM   #7 (permalink)
Registered Users
 

Join Date: Jul 2013
Location: Middle East
Default

Hi, an ultrasonic cleaner is the only way to get all the passages properly cleaned. (car tuning shop that specializes in carb rebuilds)

Ps. Jewelry cleaners do not seem strong / aggressive enough. But I got some browny points for "buying" my wife such a thoughtful gift !!!
trillian and macdad like this.
Dawiev is online now        Reply With Quote Quick reply to this message
Old 10-15-2018, 05:00 PM   #8 (permalink)
Registered Users
 

Join Date: Jan 2011
Location: Nashville, Tn
Default

trillian,

A lean mixture will make a gasser ldle much higher than normal. Your symptoms are definitely fuel and air related. A good thorough cleaning is the first course of action.

TNJET
trillian likes this.
__________________
Pink 700l Dominator; Jeti DS-14; IKON2 FBL
RWB 700l Dominator; Jeti DS-14; IKON2 FBL
Green 700l Dominator; Jeti DS-14; IKON2 FBL
Tnjet is offline        Reply With Quote Quick reply to this message
Reply




Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the HeliFreak forums, you must first register.
Please enter your desired user name, your REAL and WORKING email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself. Use a real email address or you will not be granted access to the site. Thank you.
Email Address:
Location
Where do you live? ie: Country, State, City or General Geographic Location please.
Name and Lastname
Enter name and last name here. (This information is not shown to the general public. Optional)
Helicopter #1
Enter Helicopter #1 type and equipment.
Helicopter #2
Enter Helicopter #2 type and equipment.
Helicopter #3
Enter Helicopter #3 type and equipment.
Helicopter #4
Enter Helicopter #4 type and equipment.

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Thread Tools
Display Modes

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On




Copyright © Website Acquisitions Inc. All rights reserved.
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.

SEO by vBSEO 3.6.1