Eganwp

My Feedback: (1)

Can anyone recommend the best/easiest/cheap way to build their own Walbro needle pop-off guage, with regards to parts used? I was planning on just grabbing a bike pump, 30-50lb air guage and some tubing and trying to make adapters to the tubing. Reason I ask is I'm done with trying to find someone in this city of 1 million people who has one. Been to several bike shops, lawn mower shops, carb shops, talked to several small engine mechanics who all know how to test it but are like "dang, it takes 2 seconds to test but I haven't seen one of those guages in years....", etc. NO ONE HAS A GUAGE TO TEST THIS! Pathetic really....

Thanks guys, I know the forums always come through when help is needed!

Here's something like the one I wanna build:

captinjohn

Get a radiater cap pressure tester....this is mine....may be a lot less $$ ones also. Capt,n

spaceworm

Squeeze bulb from a blood pressure cuff or outboard gas tank primer hose, gauge from Harbor freight or a pool supply store, T fitting from auto parts store or RC LHS, tubing from silicone or Tygon. Tie raps as required. Good luck. Then tell us how to do the pop off test as I have no idea. Thanks.

closetguy

My Feedback: (13)

i made one just like in the picture but i used a vacum and or a fuel pump gage works real good.
might be a little more sensitive than say a air pump gage?

jedijody

My Feedback: (1)

Pretty easy to find, here's the real deal if you want one.

http://cgi.ebay.com/ebaymotors/New-G...Q5fCarQ5fParts</p>

arobatx

Here it is for a little less $$ http://www.shopswedetech.com/popg1_p/popg1.htm

You can get em other places too.

Slats!

My Feedback: (1)

Get some 1/8th fuel tubbing, it has to be Tygon or it won't work. Attach a ballon to the fuel intake and blow. If it inflats your in luck, if not get a new one.

w8ye

My Feedback: (16)

It would be hard to do legitimate business with Swedetech as there is no contact information on the web site

I finally found it on a different site



SwedeTech Racing Engines
11583 Walmort Road
Wilton, CA 95693</p>

(25 to 30-minutes South of Sacramento and
20 to 30-minutes North of Lodi / Stockton)</p>

916.687.3980 phone &bull; 916.687.4739 fax</p>

Eganwp

My Feedback: (1)

FAIL! I wanted to use viton tubing instead... :*( LOL, thanks for the tips Ken!!! haha.

Thanks for the replies guys. Lots of good ideas. I'm gonna whip something together shortly!

pe reivers

I use Viton tubing, a bike hand pump , a bike tire non-return valve and a 30 lbs pressure gauge.
I find the 30 lbs pressure gauge range too low. 0 - 50 would be a better range. 0-15 like in the cart ad is as good as useless, because most Walbro carbs I test are in the 30+ lbs range.
The main use for the pump is to check the carb for fuel valve action and freedom of leaks. Also, when the carb is at pressure, and you as much as breeze on the diaphragm vent hole, you should see a pressure drop because the diaphragm lifts the fuel needle.

MetallicaJunkie

is this to test if your diaphragm are bad?

Kweasel

My Feedback: (29)

Its just an easy yet backwards way to reference regulator pressure, which controls carb mixture around 1/2 throttle. It doesnt mean much until you start changing the spring tension and need a way measure what changed. If an engine has an annoying half throttle burble increasing the pressure helps. If its running very clean but tends to lack throttle response then lowering the pressure helps.

captinjohn

The pop off tester I made in post #2 if you look close...the needle is about at 16 psi....real easy to see exactly when pop off occures. Tne slower you push pump handle down the slower the pressure rises. After you check this make sure carb is wet again...or it will not prime good. You need the carb wet also when you do the check. Capt,n

Cyberwolf

My Feedback: (4)

I myself use a vacuum pump seems to work ok, Been told a few different settings on the correct pop off pressure, So let here it for the pros at what they recommend. I have also been told not to clip the spring but to get a new shorter or weaker one.

pe reivers

Instead of clipping, compress the spring slightly with your caliper, and heat with a paintstripper gun. The spring will take a set and have less pop-off pressure, as well as parallel end faces.
Again, only do this if you want to experiment. Most of the time you will be sorry you did afterward.

The Ghost

A very common problem with cowled in engines is, the air pressure in flight changes the "natural" pressure on the float diaphragm. This causes the engine to run rich in flight. There are several possible fixes available. Most of the time you can simply tune your engine for flight by trial & error. However, the easiest fix is to open up the cowling around the carb area to lower the air pressure. You may also rotate the cover to different positions to see if that works. The "BEST" fix is to solder a piece of brass tubing where the vent is, and route the vent line to a better location. I normally route it into the fuse going through the firewall. It works perfectly every time! Plus, your ground tune doesn't change in flight! You can also run the tubing to a static tube on the cowl where the firewall is still open to the fuse, a lot of modern ARF's are like this with long open engine boxes.


Cheers

The Ghost

Metallica, it is for a pressure test of the carby, must be done wet. Check out attachment, straight out of the Walbro Service Manual, I have it in PDF but it is too large to post here. Send a pm if you want a copy.

Cheers

Eganwp

My Feedback: (1)

The Ghost - yes, I did tap the carb plate with a film cannister run into the fuse and still had the issue.

Just wanted to let everyone know that in my running around trying to build and or find a rad pressure tester I came across the bike pumps at Canadian Tire. Found a really nice multi function standing bike pump with multiple attachments and a reasonably high quality psi guage built in. Got it for $24 on sale. As it turns out, the "inflatable toys" nipple fits 1/8th tygon PERFECTLY! So I primed the 55, and tested the pop-off 5 times. 22lbs exactly every time, so spring appears to be fine. Anyone else looking at this should consider a bike pump like I did. Plus it can be used for many different things.

Egan

captinjohn

Not sure but the pop-off pressure should beno lower12-lbs ...will try to find out more. I guess you can go up to 20 or more pounds...but to high can cause a lean condition on reving up...Capt,n

Eganwp

My Feedback: (1)

Walbro recommends 11-12lbs. Most people have issues on these planes (maybe due to vibration?) with anything under 15lbs. I talked to JediJody and he recommends at least 20-25lbs+, so that was my aim. Some guys even run 30-40lbs, but the high end starts to get a little lean at that point.

pe reivers

Walbro says it should be AT LEAST 12psi in order not to leak under pump pressure.
Most walbro carbs have more than 30 psi.

w8ye

My Feedback: (16)

I was at the auto parts yesterday and saw what looked like a perfect pop off pressure tester with all the proper fittings. It was a sensor/radiator testor for cars. Well, it was $75. I passed and went over and looked at the two stroke oil.

pe reivers

USD75??????
You just made my day! Just in time at 23.45

Back to the pop-off use again.
A few hours ago I reduced the spring length of a zen.26cc jewel, that had a carb pop-off of 45 psi. With an 18x8 Menz prop on a paraglider the engine had
top end tuning problems. So I checked the lever spring at 11mm length before it would drop out of my caliper jaws. Using the calipers, I compressed the spring to 7mm, and heated it with a paint stripper air gun. Now the spring would drop out at 10mm. Resulting pop-off now is 35 psi.
Awaiting engine tuning results.

captinjohn

Pe Reivers
Tis good to read you way of doing this stuff. That is the way I learn from you &amp; many guys just like you. All seeking the best way to fix or correct a problem with RC engines. Just how hot does this paint stripper gun get small parts when doing this? Thanks Capt,n

The Ghost

For all those of you who would like Walbro service and setup Manuals for different carbies, Just go [link=http://wem.walbro.com/distributors/servicemanuals/]HERE[/link]

Cheers