help on OFNA Force 15

[racemania81]

hey guys need some help on the OFNA force 15 ive heard these little engines dont run too well with low pressure on the fule tank, what i need to find out is if mines playing up due to this or not, what mine is doing is ill get a good 5 mins out of it then it dies just as the fule reaches 3/4 tank so theres still heaps of fule comming through i could get it to run longer but its hard to up the idle without a brake yes i got no brakes atm, i broke the servo link and cant get it to stick back on, anyway back to the motor, i have done a pressure test on the carb and fule tank no leaks i dont know what else to try other than ask around for aquick fix or find somthing that will work.

any ideas i know these engines are not the best and its hard to find anything on the net about them, heres what i know about it its the force 15 with a slide carb and its got a big blue heat sink, i got photos around somwhere ill post one up.

http://i108.photobucket.com/albums/n7/racemania81/PICT0005.jpg

thats about the best one i got thanks guys.

i done a speed test on the car the other day got it to 93km/h aveage there was one in there running at 101km/h i done 10 runs and took the average from that. not too bad and im thinking of getting a 2 speed for it too might have some more punch.

thanks for any help you can give

[z3usX5]

I seen this problem before, where you get most of you fuel ran but right around the 3/4 mark it stalls..... le me look into this...

[racemania81]

in the pic on the tank its where the join is about there.

thanks for that z3usX5 im going out to give it a run now and see if it dose it again.

thanks racemania

[scoobie]

it could be a number of things...is the clutch in good shape? Bad clutch bearings or a hung shoe can cause what youre describing. Using the wrong plug can do it too...99.9% of all small blocks like HOT plugs. Also make sure youre not using a 'short' plug...

[scoobie]

After looking at your pic, I noticed something...its a pull start motor, but no pull start backplate. That could be a source for a nasty air leak and could be causing a ton of tuning probs

[z3usX5]

good eye scoobie... that is very true.

[racemania81]

the pic was taken before i got the pull start for it so when you say backplate what do you mean do you have a pic of one ill see if theres one at the local hobbie shop.

i took it out today and i ran 1 full tank on it but only at half idle and it ran fine i then put some more in and she fired up after about 2 laps of half i started to blip to full on the straights then the problems started as soon as i let go of throtle she wanted to die out so i brang it in and didnt seem like there was anything wrong.

so i dont know if it was just too hot or just the motor needs a good run i also dont think it was run in right so what can i do with it just run at half for a few tanks and keep trying till i get a new motor?

with the clutch its brand new so no problem there.
berings are new and the motor is in good condition i think i might need to set it up to the right settings.
i only paid $50aud for it and am not that botherd about how well the car runs as ill just get new stuff for it when i can.

thanks for your help guys

[AZRCaddict]

http://graphics.hobbypeople.net/sgallery/s269029.jpg

^^That would be a pull start back plate. Make sure the back plate you have/get is made for your engine

[scoobie]

what about the plug?

[racemania81]

yeah theres a back plate on there and the plug is os 8 i dont know what it means but its working with it in there.

thanks for your help

[scoobie]

Theres your problem! The OS8 plug is the absolute wrong plug for a small block. Its too short, and not hot enough. Get a standard length HOT plug and watch what happens:thumbs:

[racemania81]

ok thanks scoobie ill go see if i can get a new one one today.

i went to my local track today for a run got about 2 laps and she died it was like there was not enough idle in it will a new plug help this?

and what sort of plug should i get the air temps around here get to about 30c up to arround the 40's. my lhs only sells OS plugs so i dont know which one to get lol.

thanks for your help.

[scoobie]

The right plug has everything to do with a consistant idle. The plug heat range is what determines the motors timing. Hotter plug advances the timing, colder plug retards...Get a standard length HOT plug. An Odonell 77 would be a good choice http://www.amainhobbies.com/product_info.php/cPath/23_33/products_id/2120

You will probably have to retune the motor a little to compensate for the plug change.