Ofna Force 25 and starter box?

[bwillhite]

I just got my first nitro R/C car, an Ofna Ultra LX Pro! It has a Force 25 engine on it that is driving my nuts! The engine will start great when the engine is cold but, when the engine warms up it is a majot pain to start will the pull-start. I have about a dozen tanks of fuel through the engine...about a quart.

I am looking a getting a starter box, the skin on my fingers is wearing out!

Which starter box should I get? I am leaning towards the one with the 12V direct-drive motor. http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXCUC2&P=7

Any suggestions?

Thanks

bwillhite

 

[nitro boy]

i also hav a force 25 engine with only 2 ltr of fuel threw it and am having same problem!!! i hav noticed on mine that the fuel is returning to the tank from the carb even when i blow fuel threw line it still goes back to tank that is why i can't start it when its warm but if i wait 2 mins it will start again, have you checked your fuel lines when trying to restart it to see if it is returning to tank? am trying to find problem when i do will let u know, its driving me mad 2!!!

 

[Gunfighter]

http://www.dynamiterc.com/Products/Default.aspx?ProdID=DYN5610

This is close to what I bought. It runs on 2 stick batts or 12V so I can hook it straight to me trucks batt if I forget to charge the stick batts ( Which has happened more times than I care to admit "

 

[nitro boy]

have you tried adding a head shim? this lowers the compression enough to keep temp down without loosing power, i did this to my force 25 when i had the same problem as you when it got hot it just wouldnt start it made the biggest differance it let me lean it out more staying at a good temp an got more power out off it runs tank afta tank now

 

[calibrated]

I just got my first nitro R/C car, an Ofna Ultra LX Pro! It has a Force 25 engine on it that is driving my nuts! The engine will start great when the engine is cold but, when the engine warms up it is a majot pain to start will the pull-start. I have about a dozen tanks of fuel through the engine...about a quart.

I am looking a getting a starter box, the skin on my fingers is wearing out!

Which starter box should I get? I am leaning towards the one with the 12V direct-drive motor. http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXCUC2&P=7

Any suggestions?

Thanks

bwillhite

A late reply I know but, even if you do not have to, you will get more life from your Force 25 if you let it cool in between runs/tanks. If it is stopping mid tank, check the motor temp and the fuel line from tank to carby. If there are air bubbles in the line, it could be that the fuel is getting heated too much by the exhaust pressure, this would stop the motor sometimes but definitely would make it hard to start hot. With little or no fuel getting to the motor, damage to the motor can be done quicker with a powered starter.
If your motor is running too hot (over 148degC/270degF), you can try richening the fuel mixture up at the main needle adjustment. Making this right may help your hot start problems.
Happy RCing

 

[BradZ]

Sorry mate, can't help your hot start problem. But my buggy has a Force .25. When it was new, it used to rip skin off my fingers aswell. Just tough it out for a few more liters, it gets much easier once its broken in. Trust me.

 

[jriesz]

Running a force 25 in my GV Dominator atm as well. Run about a litre through it so far, and apart from the many many hours spent tuning it for first start, hasn't caused me any grief at all. In fact, it starts a lot easier once warmed up for me.

GL with the starter though!

 

[Scrogg]

They are running the engine too warm. The carb on that engine does not have an insulator insert between the carb and block. So whenever they get around 250F the carb is 250F as well. The heat/pressure pushes the fuel back to the tank.
I will not buy an engine that does not have an insulated carb for this reason.
A starter box will help tons though. You'll have to force prime the engine when it is warm by plugging the stinger. Your other alternative is to wait til it cools.

 

[ozwes007]

How many needles on your .25 Force

I would like to know which needles to adjust. I have a new GV Dominator(Race Edition) and the carby on it has 3 needles - a Throttle needle valve, a supply needle valve and a main needle valve. Which is the HSN and which is the LSN?
I can't find any documentation that describes which is which. Any help would be great as I don't want to disassemble it to find out.