MAJOR PROBLEMS with Thor 45cc 2 Stk Petrol engine....PLEASE HELP!!!

[thkoutsidthebox]

Hi folks,

I had no doubt that this was due to my inexperience, but at this point I have to wonder! So in desperation I've turned to the internet and am searching for anywhere I can post this question...

I have a Thor 45cc 2 Stroke Petrol engine with electronic ignition. I can start up the engine without any problems, but its the setting of the mixture screws that is causing me untold pain.

After many days and endless hours I managed to get the the low speed mixture screw at what seemed an ok setting i.e The transition from idle to high power was 'relatively' smooth......
.....But as soon as I put the throttle to full power, she starts coughing. I lean the high speed screw out a fraction of a degree...not coughing so much but still a bit....then I put throttle back to idle. Increase throttle to full, she revs up then gets close to full and dies suddenly. So I richen the high speed setting a fraction of a degree.....back to square one, she rev's up fine, but coughs and splutters at full throttle. I've been going around in circles and am at the end of my rope with this, I'm bringing it back to the shop tomorrow to see if they can help. When I say a 'fraction of a degree' I really mean that, an almost imperceptible movement of the mixture screw. What am I doing wrong? I even tried moving the ignition timing screw....that doesn't seem to do anything at all....

At this point the ignition timing screw position is lost....engine starts fine, but I don't know where it is in relation to its position out of the box. The mixture screws are reset back at factory setting of 1.5 turns out from fully closed as per the manual. I'm ready to start again tomorrow, but I'm not holding out much hope anymore.....

I'm very upset......has anyone got ANY advice...?....please help....

[.xXACEXx.]

i almost hate to even post because ive had little experience with rc engines...except for buggies but that engines is simular to a chainsaw engine right? i have messed with chainsaws and other small engines...my first thought is some kind of gunk in the carb or an air leak some where i had a small .o10 (i think any way) buggy nitro hawk still got it, about 20 years old...lol but any way...it had a small crack in the boot that goes to the throttle slide for the carb. it would crank,,shut off,,,adjust screws,,,crank shut off (repeat i million times...) i know this sounds elementry but...pretty much all an engine needs to run is fuel and fire...the problems come when both are not exact..if it aint geting one of those it wont run...im sorry if my post sound to vauge but as i said im more used to buggy engines and other small engines ...plus automobile engines... so i would check the fire for sure, then make sure you have some good fuel,then start off a little rich on the mixture and move it very small amounts at a time and see it it makes any diffrence at all...if not its prolly not your settings,..then i would make sure its getting fuel and not sucking some trash into the carb,but be warned..if you remove the carb..some times the gaskits will tear or rip and this too can let more air into the engine ...if it runs good at idle but falls on its face it probably the fuel mixture due to either trash in the carb,a bent screw not adjusting the fuel smoothly, bad (old) fuel or a bad gaskit not sealing properly at the carb...fuel is usualy the main problem with getting an engine to run,if it is falling on its face, is it "starving for fuel" or is it drowning in fuel...
i had an old ryobi weed eater one time that was bad for doint just what you describe ..i discovered it was carbon build up on the piston....i would clean it off...it would run fine for a summer...then next summer..same thing again..so it can be several things that make an engine run bad.....and like i said...i hate to make such a long post about all this but as i dont know your skill on engines..i wanted to explain alot more than you prolly even need...sry if this dont help ya any...maybe some one with more knowledge of the exact engine you have will give better advice..good luck

[thkoutsidthebox]

Thanks ACE, any and all comments are welcome at this point. I'm fairly ok with engines in general.....as in, I know the principles, and tinker a bit, but just can't get this tuned up right. I figure it is 2 stroke 45cc, which is near enough to 2 stroke 50cc like on a moped, so advice from all corners is welcome!

It's brand new. I've ran it in for more than the 2 hours on the instructions at this point, just idling. I'm still mixing my oil and fuel at 25:1 as per running in, and haven't switched to 40:1 yet as per normal use in the instructions.

Theres an in-line filter in the fuel tank.

Starting is not a problem, she starts after one or two turns of the prop.

I just can't get her to run 'smooth'.

[thkoutsidthebox]

Hi again...problem fixed! I can't believe that after over a week of misery with this the problem was an unbalanced prop! ARGH!!! Thanks for the advice and help. Here's a small video with the new prop.

[ame]http://www.youtube.com/watch?v=_2CvSPIXCO8


Video Url: http://www. youtube. com/watch?v=_2CvSPIXCO8



"http://www.youtube.com/watch?v=_2CvSPIXCO8"]

[.xXACEXx.]

well now thats a lil new to me ,as ive never had a prop on my weed eater. (ill admit i have thought of doing it tho) glad to see ya got it worked out..

[keno245]

hi there has anyone have a thor45cc engine up and running. as ive got one ,and ive just ran it for about half hour at 15 mins at a time but now it wont run .i can get it to fire up now and again.but it just stops. ive changed the plug the fuel. and even cleaned the carb.but it dont seem to want to run and its peeing me of ,ive spent 6hrs on it this weekend trying to run it but no luck .please help if you have any idears ,cheers kenny

[keno245]

hi there has anyone have a thor45cc engine up and running. as ive got one ,and ive just ran it for about half hour at 15 mins at a time but now it wont run .i can get it to fire up now and again.but it just stops. ive changed the plug the fuel. and even cleaned the carb.but it dont seem to want to run and its peeing me of ,ive spent 6hrs on it this weekend trying to run it but no luck .please help if you have any idears ,cheers kenny