I’m running my Poulan 42cc on gas/glow with the glow portion being 15% nitro, 10% oil in order to not loose rpm when I disconnect the glow driver. I recently replaced the ring with a Frank Bowman ring and even with this new ring it would still loose rpm when disconnecting the glow battery. However, the last couple of outings, I’ve noticed the rpm remains more constant when I disconnect the battery, which tells me that the compression has increased and the ring is seating. I also notice that I’m getting some hard kickback sometimes now when I try to start it. Is the increase in compression due to the new ring seating well causing this? Would lowering my glow portion of the mix back down to the suggested 10/10 cure this? Thanks.

You have to much nitro. You need to run 10% or less. I was running 15% for a long time. I had a bad kick back that did a lot of damaged.

I Went to 10% no prob.

Paul

I am using 20% nitro and 12% oil on my 42cc poulan with glow conversion, 2 parts high test 1 part glow fuel. For starting I turn it over with the choke on until it coughs and then turn the choke off and back flick it and it usually starts within a few trys.

What prop are you running on your engine? I have a 20x6 dynathrust I'm getting 7300 rpm. I think my rpms are a bit low.

Jake

I’m running an APC 18x8 wide prop and getting 7800 rpm. I’m using the stock Walbro 11.11mm carb and the stock chainsaw muffler. I think I could get even more power by opening up the exhaust and going with a larger carb, but I’ve already got unlimited vertical on my 14 pound stick plane and it is very quiet. I’ve ordered a Menz S 20x7 that will hopefully be in this week that I’ll try as well.

Mine is in a 15-16 lbs cap232 that i haven't flown yet. I have walbro carb aswell but my engine has an additional intake the only puts more air into the engine. i will post a picture of it when i get home. Yesterday I had an actual thrust reading of 19 lbs with a fish scale.

. The increase in compression basically changes the timing.
More compression equals more heat and that means ignition happens sooner.

Do you need to lower the Nitro percentage in your Gas-Glow fuel? Maybe not, but you could.

How does it run on top end? Does it ping or rattle? If so then you should reduce the Nitro.

If it is hard to start because of kick back but runs great after ward then it's a judgement call.

If you don't need the gain in horsepower from the extra Nitro then you could adjust the fuel to suite
You’re flying style.

I believe you could add 2% more alcohol and still have enough oil for your engine.
You will need to have someone else to confirm that, but I believe 8% oil is the real number.
That would lower your Nitro content and give you more alcohol for more catalyst action with your glow plug.

I'm glad to see things are working out for you.
Every engine is a little different, even in the same models.
You are almost there. There is something to be said for building a conversion engine.
And then to run it on Gas-Glow is the next step up.

Developing the perfect mix for that specific engine is the last thing in a long line of satisfying steps.
Except for years of dependable flying.

When the compression is too high in cars they have to run higher octane fuel to stop early detonation so maybe you could buy high octane fuel and add some octane booster to it to get rid of the early ignition. I'm just throwing it out there I'm not really sure if that would work. heres the pictures of the carb on my 42cc poulan. It made throttle linkage a bit of a nightmare but its kinda neat.. anybody else have this setup?

Ralph has it right on....

I say just run it man. It actually sounds like you are just about perfectly dialed in. A little kick back is no big deal. Try back flipping it to start.

AV8TOR

Just remember, if you wanted a "turn key", "anyone can run it" engine, you could have paid $600.00 for one!!

Hang in there. It sounds like you've got a good setup. If you ever want more power, it's easy. Just add a 13.5mm carb and free breathing exhaust. That should put you up in the 8300+ rpm range with that prop.

AV8TOR