Hornet1

It seems my G62 does not produce optimal power until I place the plane in a slight dive, then it sort of clears up with all the power it produces for the rest of the flight, make sense..? To clarify, I take off and notice that the engine does not seem to be at full throttle (but it is), after I gained enough altitude I place the plane in a slight nose dive and all of a sudden the engine seems to clear up and has plenty of power (full throttle sound). As long as I don't touch the thottle the engine runs great but if during the flight I reduce the throttle and then increase it back again to full throttle the problem comes back again and I have to do the same (place the plane in a nose down attutude to gain full throttle again). To clarify further I don't have to keep the plane in a nose down attitude for the engine to work o.k. at full trhottle, just dive for a bit, the engine clears and then works fine in all attitudes until I decide to reduce the throttle and increase it again. What's going on.

Thank you.

ifshnee-RCU

My Feedback: (1)

Hard to tell but it sounds like it's loadin up - i.e. your too rich

Zippi

My Feedback: (10)

Hornet1,

A good prop for the G62 is a 22X10, 23X8, 22X6X10. What size are you running? And as Hornet1 said it could be loading up from be not properly tunned. We need a little more info. Is this plane new are did the problem just start.

rgoldy

While you are thinking about that one, my G62 runs great, transitions fine, howls at top end but dies at anything below 2000 or so. I have tried every setting under the sun and nothing seems to work. Rebuilt the carb, same thing. When I put it away last year, it was fine.
Thoughts?

Zippi

My Feedback: (10)

rgoldy,

Not really sure on that one but you might check the pump diapham and see if it is nice and limber. I just got through going over my Extra 300LX with a G62 and found some things loose and the fuel line in the tank was spit. I give mine a good once over every now and then.

Hornet1

Thanks for the replies, I will try to lean it a little bit more at full throttle. As for the prop, its a 22x10 Master Airscrew. Yes this is a brand new engine in a brand new plane (30% Hostetler Cessna 150). I will keep you guys posted as I try your suggestions. In the meantime if you think of anything else please let me know (but from what I know I think you guys are right it should only be the top end mixture adjustement).

Thanks again for your help.

rgoldy

Re: diaphram

Put a new one in when I rebuilt it. That's what I thought it was too.

Zippi

My Feedback: (10)

Hornet1,

This is how I tweak on my G62. Set both needles about 2 to 2 1/2 turns open. Run it full throttle and with a tach get it running at peak rpm and back it off a few hundreds. Move to the low end and let it idle, then run it to full throttle and if it hesitates lean the low end 1/8 of a turn. Keep doing this until you get a good transition. Now go back to the high end and recheck.

Skipper Billy

Gas Engine Tuning
*** Carbs aren't too difficult to tune up if you know what you're doing. First of all, you need to know how the carb works and how the settings interact with each other. About 95% of all the gas airplanes I've seen at the field are somewhat out of tune. How can I tell this? Simple, at some point the engines "four cycle" in flight. Two Cycle engines are not supposed to "four cycle" PERIOD. This is caused by a rich mixture that is forcing the sparkplug to intermittently miss making it sound like a four stroke. This is not good. HOWEVER the good news is; gasoline two stroke engines are very tolerant of rich settings (most of the time) and will run fine. You'll just consume a little more gasoline than necessary, and create a little more oil mess on your plane. You may eventually foul your spark plug as well. So why do so many people leave their engines tuned like this? Simple answer, the engine will start much easier when it's cold AND there's little or no warm up time needed prior to flying. Those are pretty good reasons! But the fact is... the engine is not running like it's supposed to.

(1) The low end needle on a Walbro carb is ALWAYS the one closest to the engine, the high end needle is the closest one to the intake/choke.

(2) There is no fuel adjustment for idle fuel, only air feed set by the idle stop or servo.

(3) Both low end AND high end needles feed the top end fuel supply.

Let's tune up a Walbro!

Set the low end & high end needles to about 1 to 1 1/2 turns each. Choke the carb or prime it, until the carb is wet. Fire up the engine and let it warm up. Let's set the top end first since it's the easier of the two. Go to full throttle. Adjust the top end needle for peak RPM. Leave it wide open for about a minute to see if it changes any. Should the engine go lean, open the low end needle slightly, if this doesn't work... you will have to adjust the needle valve inside the carb.( I will explain this later) If the top end runs OK, then slowly pull the throttle down until the engine begins to "four cycle" hold the throttle there. Adjust the low end needle until the "four cycling" stops. Now lower the throttle more until it "four cycles" again, and adjust the low end again. Keep doing this until you reach full idle. Now, from full idle begin to throttle up until the engine starts to bog or hesitate. Open up the top end needle just enough to eliminate the bog or hesitation.

When this is done right, you will be able to set the throttle in any position and it won't four cycle, plus you will be able to transition from idle to full power without any hesitation at all.