I know I am in the gas section with a glo engine question, but I posted in glo several days ago and got no response, I understand if you move the post, just thought I would give it a try here.

I have been flying my Alpha 40 for the last year and trying to figure out why it keeps dead sticking when doing touch and go landings. First couple of touch and goes are fine and then after that it is a crap shoot. As I advance the throttle on the third or so touch and go, the engine dies.

I have taken of the guards on the needles off and done a ton of research on setting them. I feel I have a decent knowledge of setting the HS and LS needles. On the ground when tuning, I get a crisp transition form idle to high rpm. In the air flying around it just screams.

But on the 3rd or so T&G, the thing quits on climb out. I have changed all the fuel lines and check for tightness on the engine bolts etc...

My current needle settings are LSN 1 turn out, HSN 2 turns out and I am at 600 ft above sea level. Fuel is Powermaster 15% nitro fuel.

I'm guessing there's an air leak somewhere. Check the o-ring at the base of the carb. It might be worth replacing it. Use a little bit of red silicone around the carb base, and push down on the carb throat with your thumb as you are tightening the bolt. Check the back plate as well. Sometimes you can get an air leak through the front bearing. As long as the leak is consistent, you can tune around it. However, if it changes in volume as the engine warms up you can end up being lean when fully warm.

Irocbsa,

Thanks for the input, I will check the carb o-ring and put some sealant around it.

In normal cruise I don't get the engine problems, only T&G's. Weird.

Give as more info on the glow plug, how old is it? If the one you have is new, have you try another one? Some times the glow plugs become contaminated with debris and won't work as it should and if you check to see if it works that may not help if it is old because they may glow when tests but when back on the engine in use they do not glow enough to keep the fire going.

Sounds that it is quitting when it is working at the hardest, I would try slow flight up high like if you were about to land then go full throttle a few times to see if you can reproduce the simptoms.

Also check for air in your fuel line after it quits as that could possibly point to tank/line problems. Keep us posted on what you might find.

Try a high heat range glow plug. McCoy, or Tower Power plugs have that range. K&B 1L would work as well. You'll see a difference, but you will need to reset your needles.

Thanks for your replies, I have replaced all the fuel lines and inspected the tank. I will pay close attention to the fuel lines for air.

Tonight, I pulled the carb and checked the o-ring and it looked good. While I was in there, I RTV'd the neck of the carb and replaced it.

Next area to check will be the prop hub seal area.

What's involved in the replacing of the prop hub seal?

I will change the glow plug also.

Some good info so far. I'm not so concerned about air leaks in the front of the engine as IROCBSA suggested, these are usually consistent leaks and can be tuned around. In fact, most engines have bit of air leak designed in to limit oil flow through the front bearing area. As CARSII suggested, glo plug could have a major effect on throttle transition. Several have suggested good plugs but whatever plug you choose. be sure it is a fresh one. As suggested, plug elements can get contaminated especially during breakin. Once contaminated, they will run just fine at full throttle and they will also idle OK but will suffer in transition when you most need them. Just because a plug looks good and glows well doesn't mean it is good to use. The easiest way to identify a potential glo plug problem is by noting RPM drop when you remove the battery. A good plug will show very little to almost no RPM drop at any throttle setting where a marginal or bad plug will show a notable drop.

Be careful using silicone based sealers on a glo engine. A bit of silicone migrating through the engine can easily contaminate a glo plug rendering it useless. Nothing wrong with using a bit of silicone where needed, just be sure not to over use it so pieces can get free to migrate.

One other area to look at. Is the tank well padded? Fuel foaming from the tank being too tightly held in place could easily cause your problem. Unlike gasoline fuels, most glo fuelsl foam quite easily and can cause all sorts of problems.

Great info, Truckracer thank you .

No foaming in the gas tank. I changed the glo plug and am planning on flying it tomorrow to see if that helps the problem.

I will get back with results.