dI PREDATOR Ib

hello there im fairly new to the hobby and i bought my self a hobao hyper 8.5 , it did come with a ofna 21 engine but allmy pals were running 28's, anyway i sold my .21and bought a mac star .28 second hand, it was a clean engine lots of compression and looks like its not had much use and well looked after ,

the problem is the performance when i got it , it seem to be sluggish low down but went like a rocket at top end when it got going , so with that ive had a little tinkle and now goes well low down but stalls when getting a move on , im sure its not due to a bad engine . so played with it again and again to no provail i have tried putting it to the factory settings there no good i followed these instrucions which is my actually my engine but they didnt seem to work...

http://www.cmldistribution.co.uk/dia...MacStar_28.pdf

then i came across these settings i tried these but still dosent work as both settings are completely different


http://www.dynamiterc.com/ProdInfo/F...ch28_manua.pdf

so can somebody please help me as i am so stuck and frustrated and i am on the verge of tossing it in the bin and taking up chess .

many thanks matt

hrdcoreglf

I owned a macstar and wasnt that happy with it. I would have stuck with the .21 in the buggy. The macstar was a touchy engine. When you are making adjustments, make them very small adjustments like 1/12 of a turn at a time. Set your high speed needle (HSN) first, so that you get good high speed passes. Then you can adjust the low speed needle (LSN) to get good reaction time on the throttle trigger. You cant tune until your engine is at operating temp.

dI PREDATOR Ib

i have tried this still hasnt helped ive been so carefull with delicate turns and still i get quite abit of bogging down does the carb have jets in like a normal carb that may need cleaning or are they just needles in there , my friend has the same engine as mine and his runs perfectly well ive even tried top copy his settings but even then its just a guess by eye

cheers matt

tommygun32

Predator,

Mate, have you sealed the engine up? New plug? Checked for any air leaks in the tubes and petrol tank?

BTW, chess is for when it rains and you've already stripped and rebuilt your car twice...

dI PREDATOR Ib

hello

crank cases i havent looked at within but from out side there seems to be no leeks or cracks and the carb is sealed well, the spark plug is new im using a mccoy mc 59 dont know if thats correct or not, im using 15% fuel , dont know if thats correct either so any hints and tips would be greatfull .

i would take it to my local model shop and get them to sort it and tune just to get it running right , i would happily pay , but they dont tune them they havent the facilaties and my local model club is an hours drive and i would feel very stupid just to turn up with a broken car with not much of an idea what im doing and asking someoneto help ,if anyone could help me at all , i just cant seem to get it right does anyone know who make the mac star 28 because im lost now is hobao or ofna

thanks matt

tommygun32

Matt,

I don't know or have experience with your engine. Is it a pull start?

When you say the carb is sealed, have you run a bead of sealant around the carb where it meets the engine case? Have you run a bead of sealant around the backplate?

Have you tested the fuel tank for any air leaks or the fuel tubing for air leaks?

dI PREDATOR Ib

alright peeps

checked fuel lines and tank there fine no splits nicks or rips in the pipes, tank is sound,
the carb hasnt had sealant but is a very tight fit with the screw loosend right off
,
it is a rotor start and that hasnt got sealant didnt know ihad to seal will that make a differance , i did take it off and it seem clean and dry enough as innot leeking but may seal it if you recomendit , is there any thing in perticular or will normal gasketsealant work.

another thing that has caught my attention is the that my mate has the same engine or appeared to be the same at first , they are identical in every way apart from the cooling fins ,
his says mach 28 on the top of his and mine has mac* 28 on top , now ive set my needles to the as his but that dosent even seem to run right , he has a 13 tooth bell house i have a 14 how much differance would this make, and looking in another forum else where i see there area couple ofdifferant types of mach engine

1/ mach 427
2/ mach star

one is newer then the other i think im not sure is there a way of telling them apart and how do i tell and are the settings differant

thanks matt