I have a magnum .91 fouur stroke and need to adjust the valves how do i do it? do i just turn the two screws on top of the rocker arm assembly or what? it isnt giving me ebough rpm it like idle when the throtle is wide open. the carb is fine drawing feul into the engine it runs but no rpm?????????? need help

MAM had an article about it. I think you will find it on their website [link=http://www.modelairplanenews.com]here[/link]

i dont seem to see it in the link must been a while ago

Turning the screws is the way to do it...

The trick is knowing how much to turn. I don't know what specs Magnum uses, but there is usually a slight gap (.001") between the Rocker Arm,and the top of the Valve. Maybe you could get that from the company.

And are you sure that the valves NEED adjusting? How old is the engine, how much has it been run?

Are you sure it's not some other problem?
Dennis-

Well It was the rocker arm and it was damn loose on one side so i took it down to a hobby shop and had them fidle with it then they got it running a whole lot better than it was i still thou need to adust the carb to where i can have it idle without shutting off.[:@]

All 4 strokes need to have the valves adjusted periodically. First time, right out of box, make sure factory setting is correct. second time, immediately after a couple of tanks of fuel, initial wear will take the high points of the pushrods and cam and cause need for some adjustment. After that, after every couple of hours of run time check things out. True for all brands, no particular brand is more immune to wear than the others.

this guy that helped me out says he only adjust it every 3yrs or so not very often. i'm still having real trouble getting this engine to run at idle but can't seem to find that sweet spot once i start messing with the didgetal trim on the radio to were i think it's going to run it suddenly stops i just dont know what to do. and i feel like i'm wasting my fuel and time. do you think it might need a new carb anyway? it's really weird how this engine just does not want to run at idle i sometimes think i got to the piont where it runs idle then i put throtle on and the idle just dies!! it's really iritating that this is happening and i'm afraid i'll have to miss the cross cuontry help!!!!

i really need to know how to set the carb right to were it will run at idle perfectly without dying on me which it seems to be doing i need to adust (not the idle stop screw) the screw that's in the throtle arm kinda like a brass color screw wich controls i think the idle of the engine. i'm getting really confused on how to do this without much of the maneuls help please can some one answer this very soon while i'm still on?

First thing that you need to do is run about 4 to 5 tanks of fuel thru this engine at about 4000 rpms to start the break in process. The engine needs to be run very rich at the beginning. After 5 tanks of fuel you can start leaning out the high speed needle and low speed needle. How much fuel have you run thru your engine? It takes about a gallon before you can get them to idle right. It sounds like you have the lowspeed needle to rich if your engine dies when you advence the throttle from idle. Try setting it back to the factory specs and start from there. Use a tach and set the high speed needle to the highest rpm that you can get. Once you get max RPM, back the highspeed needle off about 400 RPM. Next use your throttle trim to set the idle to the point that it will run without dying. Next advance the throttle from idle to full and see what happens. If the engine dies turn the lowspeed needle in about 1/16 of a turn and try it again. Keep doing this until you get a smooth transition from idle to full throttle. Each time you do this use your throttle trim to get the engine to idle at its lowest point with out dying. I have found that the lowspeed needle on these engines needs to be turned in quite a bit from the factory setting. These engines take some tuining to get just right but once tuned they are great running engines. I have about 2 gallons of fuel through mine and it just keeps getting better with every tank. Hope this helps.

Rick

What fuel are you using

Does it die on you with the glow power on the plug? What plug are you using? I have had good luck with the OSF plug.

You can download the manual from (http://www.hobbypeople.net/gallery/210970.asp)

ZB