I had a magnum 52 four stroke on my 4*40 last summer (first summer flying ) and it flew fine, albeit a little slow. I ended up pretty much flying full throttle the whole time doing low flybyes with a grin on my face. I've since decided to up the engine size so I put a Thunder Tiger .65 (GP61) 2-stroke that I had laying around [>:]....Ought to be a blast.

Hi all,

Can anyone tell me what is the purpose of Choke valve in the 4 stroke engine?


Thanks

They're actually pretty useless. I just take them off. The easiest way to choke a 4-stroke is to just plug the muffler with your finger and hit with the starter for a quick sec. Make sure you don't have the glow sarter on when you're priming it.

Thanks

Mody

I have heard of a problem with the magnum. The throttle lever is right behind the engine and is hard to connect because of the fuel tank. Is this true? Read the reiview at hobby people. Thank you

I have both a Magnum 52 and a Saito 56, both have the throttle in the center. I bought a Dubro 4 cycle linkage set up , but have`nt installed it yet. The Sig 4* plans show a location for the 4 stroke push rod.
Also I have started to use flexable throttle cables which seem to work much better then a solid wire one.

Well just purchasd the magnum .52 ,and O.S 4 stroke type f glow plugs. Which fuel should I use to break it in. Can I use 15% nitro? Any tips on break in. Thank you.

The,manual recommends 10%nitro with at lest 20% castor. I used Omega 5% as that's all I could findto break mine in.
Magnum does no recommend synthetic fuel in their engines.

Can I use coolpower(the green fuel). 15%

I'd only use coolpower if you added a healthy dose of castor oil to the jug, expecially for break in.

OK. So what fuel do you reccomend for break then running. Thank you

I would (and do) just use Morgan's Omega fuel. It's part synthetic and part castor oil.

Thanks. 10% on break in then can I run 15% after that.
Thanks for everything

I have 2 strokes and 4 strokes and dont find either one particularly difficult to tune. The 4 stroke is probably a little more so due to the fact that its harder to tune by ear. I generally use a tachometer to confirm my settings.

Unless you have run an RC engine too lean they should be good for years of flying without any problems. In fact after a good break in I rarely touch the needles except if there is a big change in weather conditions. I cant even remember the last time I adjusted the needles on my 4 stroke that I fly all the time.

So your comment that its hard to set them running well I wouldnt agree with. It just takes some experience. It would be good if you could work with an experienced modeler to get your engines running right. In my personal experience 90% or more of engine problems have to do with tank location or a hole in the fuel tubing. I have supertigre, thunder tiger, magnum and royal engines in various sizes and they all run great. In fact I havent had a dead stick in probably 9 months or so and I fly every weekend.

My personal preference is for 4 strokes I like the sound and throttle response.

I agree, they are useless and if you leave them on I think its pretty ugly to see an allen wrench head sticking out of your cowl. Personally I dont even worry about priming. My personal preference is just to connect the glow starter and use an electric starter. It takes a second or 2 for it to prime itself and then it cranks right up and even thats only for the first flight of the day. On following flights the engine fires up immediatly.

Yeah I think you will see a slight difference in performance. I wouldnt fly it full throttle all the time like you did with the magnum 52.... that would be interesting

Did you follow the manual on break-in procedures?

Yes I broke it in as per manufactures instructions. Put about 8 flights on it running a rich setting. The last couple of flights you could tell it was starting to get broke in
I ended up putting the Magnum on my clipped wing Cub, the bolts holes were them same as my ST GS40.
I have a Saito 56 & 72 and will probably mount the 56 on the 4 * when it`s done and put the 72 on my Ultimate 40.

Thanks I have to get fuel before I can break my engine in.

I`m getting closer. Decided to go with the Saito .56. Hope to maiden this weekend. Maybe some duct tape would speed things up?

Keep workin' Robbie, You got a lot to do before the weekend!

I have all 4 st engines [10] and I use 10 % fuel in them and they run fine.
Hey Traxxman your handel sounds suspicously like mine, maybe we have simelar last names
rctrax

Yeah, your right, but as long as the weather stays like this, I got a shot at it.

Haha yup sur are similiar