HK_Shooter

Hello All,

I'm working on getiing my GMS .61 ringed 2-Stroke engine set up for my maiden flight in a PT-60 trainer. I'm having problems getting the low speed idle set correctly. I've run 2 tanks (12 Oz.) of 10% nitro Omega fuel through it and I've got the high speed set. I've been told to set the low idle with the "pinch test" so that the engine speeds up before it dies when you pinch the fuel supply line. The only way I can get that to work is if I leave the glow driver on the engine. If I take off the glow driver off it dies immediately ( I'm guessing because it's too rich). If I adjust the low idle so it idles without the glow driver then the engine dies immediately when doing a pinch test. (i.e. doesn't speed up before dying.) For the pinch test to work I have to have the low idle needle out about 1 1/2 turns. For the engine to idle without the glow driver it can only be out about 1/2 turn.

HELP!

Danny

donw8585

hey , if ur engine dies or changes speed after the ignitor is removed means check your glow plug, thats most likeily ur problem , a good round about number of turns your high speed should be running at 1 1\4 turns open , maybe a click or two open more ,(just to be safe) and as for ur idle , start with it open 2 full turns and adjust it from there , but remmember , chnage ur glow plug , maybe its worn out , maybe its too hot or too cold for your motor, and change ur fuel lines , cuz its possible to have a pinhole, well i gave my 2 cents so i hope it helps,
Don

Dukester

My Feedback: (31)

Danny,

Definitely try a new plug. I have seen some people say that when you break in an engine, some of the metal that wears in the engine can be deposited on the plug element. This coating causes the element to have less surface area so less catalytic action to keep the plug hot and engine running. Try a new plug and see what happens.

Also, don't try for a super low idle on the new engine. Until broken in better, you may need a medium idle to keep it going until it gets run in more.

Duke

Homebrewer

My Feedback: (8)

2 simple engine rules to always live by whenver you have engine problems.

1. Replace glow plug

2. Use fresh gallong of fuel.

If those two dont' work then do more troubleshooting.

Kaos Rulz

HK_Shooter

Your engine will need a lot more fuel through it before it is fully broken in. It's a ringed engine and those rings take a good 1/2 to one gallon, or more to fully break in. Just set your idle as best as you can and fly it. You'll notice that you can slightly lean the engine out as it continues to break in. Once you can no longer lean it out with further increases in RPM's, you can consider it broken in. Until then, keep good plugs in it and adjust the idle as best as yoiu can.

HK_Shooter

Thanks for all the help guys,

It's amazing what a new O.S. plug will do for ya. Got it to idle down beautifully with a nice smooth throttle response. Now I don't feel so nervous about taking it up on it's maiden flight. (And my first in 13 years!)

Thanks again, I would never have thought to change to a new plug.


Wish me luck.

Shooter

airborneSGT

My Feedback: (15)

I have a similar problem, but on the opposite end of things. I can get my engine to idle fine, albeit slightly higher RPM because its new. However, when I try to throttle up, it just quits. If I slowly throttle up, it will run just fine. I have adjusted the low end needle to get it working better. However, now the engine just kinda sputters every few minutes instead of running smoothe. I will get the plane off the ground, and then the engine starts to just hesitate or sputter when I throttle up. At lower throttle, everything seems to be fine. I am just wondering what I am doing wrong. I have changed both the glow plug and gone to a new bottle of fuel. The suspect enging is a .46 thundertigre running an 11x6 prop in a light weight low wing aircraft.

Any suggestions?

Kimhoff

My Feedback: (22)

As you describe you problem in the first part of your response the engine sounded lean. It now sound like it is too rich. There is a fine line between lean, rich and just right.

P-40LUVR

I hope you enjoy you're GMS as much as I am...I have the .47 size and it's one of my best running, idleing engines...better than any of my 2 OS engines and less money...imagine that!

HK_Shooter

Yeah, I am having a blast with it and it hasn't even been in the air yet. Went to the field last night and had some of the experienced guys check out my PT-60 before I try to maiden it. I had to come home and make a few adjustments to it one of which was going from an 11X7 prop to a 12X6. That helped bring the idle down even lower (I wouldn't have thought it was possible) and now it sounds beautiful at idle. Had a little bit of a bog when running the throttle up fast but fixed that by leaning it out.

Shooter