HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Jan 20, 2012, 05:31 PM
Demonstrations on Saturdays!
gravityking's Avatar
United States, CA, Woodland
Joined Jan 2012
366 Posts
Quote:
Originally Posted by CryHavoc View Post
Hey Gravity, your model sounds good. I'm gonna put mine in an ARF Kawasaki Hein. The engine will stick out but its an ARF and I just want try the engine for now plus I wont have to deal with possible cooling issues while I figure it out.

Mike
Yea that pointy nose makes it hard to hide anything but electric under there but they look good either way.

And now that you mention it I guess I'd better build in air flow exhaust into my cowl! Fortunately the Bonanza has it stock just ahead of the LE of the wing.

Oh if it was all that easy!
gravityking is online now Find More Posts by gravityking
Reply With Quote
Sign up now
to remove ads between posts
Old Jan 21, 2012, 09:10 PM
Demonstrations on Saturdays!
gravityking's Avatar
United States, CA, Woodland
Joined Jan 2012
366 Posts
Just put 1/2 hour break in time on mine. 10X6 prop as suggested. So far so good.

Kudos to fiery for sharing the proper low speed needle location. And he hit it on his evaluation of the manual. Better have history before trying this one cold.

Just threw up pics of proper screw locations but as he said, regular nitro stuff.
gravityking is online now Find More Posts by gravityking
Reply With Quote
Old Jan 22, 2012, 02:30 AM
UAS Pilot/Tech Instructor
CryHavoc's Avatar
United States, CA, San Diego
Joined Apr 2000
1,476 Posts
So wonder what that screw underneath the main needle is??? Mid range adjustment???

I got rained out down here so no running. With football and errands tomorrow I think its a bust 'til next weekend.

Mike
CryHavoc is online now Find More Posts by CryHavoc
Reply With Quote
Old Jan 22, 2012, 04:03 PM
Demonstrations on Saturdays!
gravityking's Avatar
United States, CA, Woodland
Joined Jan 2012
366 Posts
Good question. Thought once I got some more time on it I would fiddle with it. But getting more time on it is proving to be a challenge!

Set it up same as yesterday, stuck the starter on it, primed right up the continued to blow fuel out the venturi because I guess the engine couldn't handle it all! Pull the fuel line and cleared it out in the usual manner. Reset the high speed to 1 1/2 turns and tried again. Same thing. worked the high speed needle in to eventually closed where she cleared out again and died. Back to original setting again and same thing, flooding. Never touched the low speed yesterday as I was running steady around 3000 rpm as suggested so started working it in 1/4 turn at a time to eventually closed. Fired up cleared again and stalled. Turn low speed back out 1/2 turn and floods.

Now if I had any time on it I would say it's a dirt problem. But from the pics above you can see the big 'ol fat filter on her. How could I get dirt?

Any suggestions before I open the carb? Actually I thing I'll remove the fuel pump first and try it.
gravityking is online now Find More Posts by gravityking
Reply With Quote
Old Jan 22, 2012, 04:39 PM
Registered User
fiery's Avatar
Hervey Bay, Queensland, Australia
Joined Mar 2008
539 Posts
Ngh 9gt

Thanks for the kind feed back guys.

Don't try to move the screw marked "low speed" in the manual, it is a set screw of some kind and is not easily moved. The slot at the end for a screw driver will deform when you try to back it out. I believe it is locked in with devcon or similar.

I have yet to dissassemble my carb, which is defective. Once I get to it I will report my findings. I hope it is something simple. HiModel don't include a warranty card for the engine.
fiery is offline Find More Posts by fiery
Reply With Quote
Old Jan 22, 2012, 04:59 PM
Canadian Bacon
flypaper 2's Avatar
Kingston, Canada
Joined Jun 2004
12,749 Posts
Sounds like the fuel pump pressure is to high. Had a pumped OS61 that did pretty much the same thing. The instructions said not to touch the pressure adjustment screw on the pump as it was factory set. This is a case where I shouldn't have read the instructions. It was adjusting the spring pressure opposing the crankcase pressure. Once I backed the pressure off a bit, it worked great. Another point, if it uses a needle and seat to control the fuel flow like the Walbro, it could be as simple as the needle stuck open or a piece of grung holding it open. Hope this gives you a couple of things to look at.
flypaper 2 is online now Find More Posts by flypaper 2
Reply With Quote
Old Jan 22, 2012, 07:29 PM
Demonstrations on Saturdays!
gravityking's Avatar
United States, CA, Woodland
Joined Jan 2012
366 Posts
So flypaper, which way do you turn that screw? Ran it gravity feed just fine. Put another 15 mins break in time on it. Must be the pump pressure.
gravityking is online now Find More Posts by gravityking
Reply With Quote
Old Jan 22, 2012, 08:16 PM
Canadian Bacon
flypaper 2's Avatar
Kingston, Canada
Joined Jun 2004
12,749 Posts
I'm not familiar with that particular carb, just the method that they work. To do the same thing, setting the pressure with a Walbro, you have to cut the spring, but that's a last resort. I'd be finding out if it does have a metering needle valve. Do they have a parts breakdown anywhere.??
flypaper 2 is online now Find More Posts by flypaper 2
Reply With Quote
Old Jan 22, 2012, 09:48 PM
Demonstrations on Saturdays!
gravityking's Avatar
United States, CA, Woodland
Joined Jan 2012
366 Posts
It's not integral with the carb. It's pictured above. Carb is fine since it runs gravity fed. If Mr. Chow doesn't chime in with a firm answer I guess I'll crack it open to see how it works and go from there.
gravityking is online now Find More Posts by gravityking
Reply With Quote
Old Jan 23, 2012, 12:14 AM
Registered User
turk1's Avatar
Istanbul, Turkey
Joined Aug 2004
847 Posts
Unfortunately Mr Chow is in holiday now due Chinese new year break.May be he pops up in a chance.If I were in same trouble,I do think to put a return line to tank using a T just before the fuel nipple on the carb.
Also though I didnt have any of that engine I am thinking possibility of liquid fuel in pressure line from crankcase to fuel pump causing pump working defectively,any thoughts?
turk1 is offline Find More Posts by turk1
Last edited by turk1; Jan 23, 2012 at 12:20 AM.
Reply With Quote
Old Jan 23, 2012, 05:28 AM
Registered User
Kansas City
Joined Apr 2010
633 Posts
If there wasn't a pump involved, it would sound like the intake timing is off.
Lifer is offline Find More Posts by Lifer
Reply With Quote
Old Jan 23, 2012, 05:35 AM
Canadian Bacon
flypaper 2's Avatar
Kingston, Canada
Joined Jun 2004
12,749 Posts
Yes, I realize it's a separate pump but the principal under which they work is the same. The one on my OS is a separete pump. Turk: A pinhole in the fuel pump diaphram, loose or warped cover can cause fuel to leak into the crankcase, sort of fuel injection, causing it to run rich. Sometimes you can see fuel pulsing back and forth in the line, but you shouldn't see it moving towards the engine.
Some weedwackers do have a return line between the pump and carb, back to the tank.
flypaper 2 is online now Find More Posts by flypaper 2
Reply With Quote
Old Jan 23, 2012, 01:22 PM
Registered User
Joined May 2009
380 Posts
what's the verdict? Is this engine acceptable? From the specs it looks like a .40 in power.
davidgp is offline Find More Posts by davidgp
Reply With Quote
Old Jan 23, 2012, 01:55 PM
UAS Pilot/Tech Instructor
CryHavoc's Avatar
United States, CA, San Diego
Joined Apr 2000
1,476 Posts
Flypaper..... I think you are giving wrong information. The OS and Walbro pumps are completely different even if they do the same function. Using one to diagnose the other is going to muck something up fast.

There are no springs in the pump section of a two stroke version of the Walbro. On a negative pulse from the engine, a flapper valve is opened letting in fuel, on the positive pulse it is closed and another flap opens forcing fuel to the engine. Thats all there is, chambers and a flexible diaphram. Fuel regulation is done in a seperate section. In a Walbro, there is a little spring and linkage, called the pop off valve. This valve regulates how much fuel is sprayed out. Small chnages to the linkage changes the amount of fuel regulation. Its a simplistic explanation but the point is made. On this engine, the fuel regulation is done at the carb. I haven't popped the carb open so I'm not sure how the regulation is done.

On the OS, the pump and regulation are done at the same time similar to, if not the same as, the Perry pump system. Changing the spring tension changes how much fuel is sent to the carb.

For comparison purposes, this engine is more like the YS pressure/regulation system than the OS/Perry.

BTW.... The return line on those weed wackers is only those with a primer bulb. The return line is only returning excess fuel once the carb is primed.

Gravity,
That big screw on the pump is simply holding the cover on. Just like a Walbro. As far as I know there is no pump adjustment. If for some reason there is too much fuel getting in the engine, there is something wrong with the regulator. Most likely there is some crud or foriegn matter holding something open. Just because there is a filter doesn't automatically rule that out.

Mike
CryHavoc is online now Find More Posts by CryHavoc
Last edited by CryHavoc; Jan 23, 2012 at 02:38 PM.
Reply With Quote
Old Jan 23, 2012, 03:00 PM
Canadian Bacon
flypaper 2's Avatar
Kingston, Canada
Joined Jun 2004
12,749 Posts
There is no spring in the walbro pump, only in the metering section which I was refering to in post 66. The spring in the OS pump controls the fuel going into the engine, the same as the spring in the metering section of the walbro controls the fuel flow going into the engine. Worked enough on these little suckers in the small motor business over the last 35 yrs. before I closed my business and retired.
flypaper 2 is online now Find More Posts by flypaper 2
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
For Sale Prop Chart and Thread finder for any Glow or Gas Engine unclegeorge Aircraft - Fuel - Engines and Accessories (FS/W) 2 Dec 10, 2011 11:31 AM
For Sale Prop Chart and Thread finder for any Glow or Gas Engine unclegeorge Aircraft - Fuel - Engines and Accessories (FS/W) 2 Oct 14, 2011 11:44 AM
For Sale Prop Chart and Thread finder for any Glow or Gas Engine unclegeorge Aircraft - General - Miscellaneous (FS/W) 0 Oct 07, 2011 10:46 AM
For Sale Prop Chart and Thread finder for any Glow or Gas Engine unclegeorge Aircraft - General - Miscellaneous (FS/W) 3 Sep 23, 2011 11:25 PM
Sold NGH GT17cc gas engine NIB ibcinyourc.com Aircraft - Fuel - Engines and Accessories (FS/W) 4 Jun 30, 2011 10:35 AM