cymaz

Thankyou

Gizmo-RCU

My Feedback: (27)

I used "Copper Coat" to seal mine. Loc-tight is designed to hold fastners(bolts, etc.), not sealing and can be difficult to remove after it sets. BTW this is really a basic engine and easy to take apart and re-assemble if you pay
attention. Not a daunting job.............Just several Allen wrenches and a cresent wrench.

Greg Wright

My Feedback: (6)

When i was running the Zenoha's back in the day. I use to run them with a 20x10 prop and this was in warbirds. I was once told that the zenoha's are not timed to run at the high RPM'S like there instructions say. These engines where made for yard equipment like weed wakers and chain saw's and they still are, so they really like to be loaded up to make them work more efficiently. The more pitch you use the better there performance will be. As for carburetor settings. I use to set mine up with the low end needle being turned out to 1 1/4 turns and the High needle turned out to just under 1 turn. I would not use the Bell mouth on the carburetor at all. To me they where worthless.

ccostant

My Feedback: (38)

I use regular unleaded 87% straight from the pump.

warbird_1

My Feedback: (61)

i have been running stihl 50:1 mix in all my zenoahs for years . i have some oil blow out but not bad. i have run that mix in engines from g-23's up to g-62's with great performance. 32:1 is old school especially if your running synthetics. if your getting a lot of blow out from the carb a velocity stack may help .

jmpups

My Feedback: (1)

I have been using Amsol 100:1, mixed 50:1 in all my Zenoah G38, G45 and G26 engines for the past 10 years, and never had any problems. JMPUPS. I also only use non-ethanol 90 octane gas.

Truckracer

My Feedback: (19)

If the engine is properly tuned, the amount of oil coming out of the exhaust will be minimal, regardless of fuel: oil ratio. If you are seeing excessive oil on the bottom of the airplane, either something is wrong with the engine or it is not tuned. There can be an exception with side intake engines. In a few cases, airflow across the carb intake can suck fuel out of the carb and it will be deposited on the side of the airplane. A velocity stack usually minimizes this problem. You can easily tell the source of the remaining residue by wiping it off with a clean white towel. If it is the same color as the oil you are using, it is raw, unburnt fuel and not exhaust residue.

Certainly, a few spots of oil are normal and expected from any 2 stroke engine.

FireBee

My Feedback: (34)

Cymaz, kinda long answer but I hope this helps you and others. Six years ago I ran pennzoil at 32:1. 93 octane gas. Good combination but kinda messy.

Last 5 years all my engines (zenoagh, 3W, FPE, Brison and range from 38-100 cc's,) switched to synthetic Amzoil Saber. 80:1 with 93 octane. I was a little scared to try 100:1 as my mentor uses 90:1 for past 16 years.

Here are some numbers for you to work towards after you fix the carb tear. I'm at 40 ft sea level.

Tuning:
Synthetic oil required a very slight leaning of the low end needles across the board. For my G-38's. now set at 1- 1 1/16 turn out. High end at 7/8 - 1 turn range. Your low end needle will control the idle and mid range and up to about 75% throttle. Then high end needle takes over. Set low end to run at about 2300 rpm. Then set the high end to max rpm. Go back to the low end and lean out until idle at 1900 Rpm range. Go back to high end and check the mid range response and set max rpm again.

Go back to idle for 30 seconds and now check throttle transition response back to to full rpm. Low end needle controls most of the throttle response. You should be able to go to full power at a slow rate ( 3 seconds from idle to full ) or a very quick ( 1 second) with no choking at mid range when set properly. Finally I set idle with radio trim centered by adjusting the amount of throttle throw (percents) on the transmitter. after putting the cowl on you might need to bump up the idle about 50-200 rpms more to get a good consistent idle and not overheat. Finally I set set my transmitter with a throttle cut off (30%) to one transmitter switch for safety.

My three G -38's (all magneto version) they idle at 1650-1800 range all inside cowls. Max rpm on the ground from 6500 to 7000, depending on the prop.
Never had a dead stick or wipe off my planes; except after 3 to 4 day events when I pack up. 1 paper towel.

For WW-1. I use Xoar 20x8 beechwood prop on my 1/4 scale 80 inch Nieuport 28. This would be very similar to your Tiger moth. A 22x8 is also a good prop for biplanes.

For WW-2 warbirds I use Xoar 19-10 flaminated or more rpm and better takeoff power. Or 19-8 Xoar laminated. These run at 6800 - 7100 range. Also a 18x10 Mejz works well.

Good luck.

zacharyR

My Feedback: (5)

synthic oil and dino oil the issue isn't how clean your pane is dino oil has heat spots where synthic oil doesn't have heat spots it's all even wear and even heat ..

you can use either oil just fine

Truckracer

My Feedback: (19)

What is a "heat spot"?

cymaz

Really well done thank you,useful for other G38 owners as well

Copper coat gasket seal, new gaskets and wooden prop now on order

dadragon

all wood props for me too and avgas + penns air cooled at 40:1 my feild is at 5800 ft

cymaz

Still waiting for the gasket and parts.....time is ticking on
I have put a new tank, plumbing and carb feed. That will be one less thing to worry about. There was a lot of $h!t in the tank and the stopper was breaking up.
I will report further when I get the bits.

Captain John

I got a G38 with a the flywheel ignition and it will Idle so slow its hard to believe. Other guys say they never seen a G38 Idle that slow. Starts really good too. It is a real low hour engine with hardly any time on it. Capt,n

cymaz

New parts now fitted. Sadly the weather is now poor. Will try and start it soon..........I will keep you posted.

jkswan

The G38 is a long time "standard" that has been serving modelers well for decades. I love mine, its very dependable, starts easy and runs very consistantly every flight. About 8 or so years ago I broke it in using regular 89 octane pump gas and Pennzoil Outdoor mineral oil mixed at 40:1. After that, (many, many flights) I switched to Bel Ray Synthetic motorcycle racing oil at 50:1 per mfg's recomendation. I believe most any 2 stroke gas engine would run just fine using synthetic oils mixed at the oil mfgr's recomended ratio. Some engine mfgr's recomend more oil using a non-synthetic oil during break in, especially those engines that don't use needle bearings on the con rod.

Like others have stated, if the carb is properly tuned you will see very little residue from the carb or exhaust. I just get a few black specs from the exhaust after a flying session.
I've tried using venturis on the intake on several different engines with mixed results. Some times with the intake out in the air stream, even without a venturi, the air flow tends to draw gas out of the carb before it can be drawin into the engine. This can cause some residue also. I've concluded they really are not necessary, but can be useful for finger choking a coweled in engine when you have an opening cut in for the intake.
I'm currently using an Xoar 18x8 but a 20x6 would also be ok depending on the plane and type of flying. An 18x10 seemed to load the G38 a little too much, preventing it from spooling up as quick. Lower pitches generally give less speed but more vertical pulling power. Depends on what you want. I put my G38 on a old CH Electronics 90" Roadrunner to break it in but it turned out to be such a good combo, I just kept it for a fun flyer.
I'm using a B&B cup mount with a spring starter. With the throttle wide open, I just rock the prop back n' forth through compression with my finger over the carb until I feel the wet gas, then back to low throttle, turn on magneto and it fires on the first try almost every time.
Love the G38.
Jerry

3136

That's a bit of a worry, are you using a brown dubro gas stopper?

jkswan

I've had trouble with the Dubro brown stoppers, distorting and leaking, I think I even had one crumble on me after a short time. Isn't the brown supposed to be for glow or gas? The old black stoppers made specifically for gas still seem to work best for me.

3136

The brown ones are for Gas http://shop.dubro.com/p/gas-conversi...pper-qty-pkg-1

cymaz

I had it in my box of bits. Looked the same colour as a Dubro but wasn't in a packet
The new stopper is a real Dubro. It said so
3136, that's deffinately the one I have now.

3136

I hope you didn't suck any of that crap into the carb, I hope you have you been using a walbro felt clunk.

cymaz

Felt clunk is used and I did clean the filter in the carb...there was only a few specks of dirt in that.

cymaz

Right update, after replacing all the pipe work, new felt clunk, 2 new carb gaskets, new nylon carb spacer all sealed with copper high temp gasket sealer, it has done the trick .

Primed up well,carb choke closed and coughed with ignition on. Opened the choke and two light flicks later sprang right into life.
Well pleased.
Still chucks out a bit of oil but I'll live with that. I will get a different prop or two for a trial.
Thanks for all the help.
I used Castrol Power 1 Racing fully synthetic oil. Got 1650-1700 on idle and 7200-7300 WOT. 32:1 Ratio mix.

Gizmo-RCU

My Feedback: (27)

Great, you now have a normal healthy G-38! Well done.

FireBee

My Feedback: (34)

Cymaz, your diligence has paid off and you now have a sweet G-38 that will provide you years of trouble free running/flying. Enjoy the summer flying, when it finally comes.