Hello, i finally got my car ready but the starter won't turn it over. I have a 9.5 with a hyper .21, the box i have has a 550 type motor that uses two 7.2 volt ni-cads, i charged them but it does not have much power, this is my first box and i'm confused. I see some boxes have a large motor which uses a 12 volt deal, will these boxes do the trick, any help would be great, Thanks.

The motor is to tight to turn over.So use a hair drier or a heat gun to get the motor warm so it will loosing it up and then try to bumb start it you should have no problems at all.

Thanks for the reply, i had airplane engines with the same problem, i've used heat on them,If i take the car away from the house i won't have access to power , are there any boxes that would work without heat, ok thanks.

not a 100% sure but after a couple of tanks i dont think you will have to preheat engine in more.

Try loosing the glow plug 1/8 of a turn. Don't forget to tightem it after the engine starts.

Neil, thanks for the info, that works good with my roto start, but no luck with my box, i think i'll buy a new one, 12 volt, and use a battery with alot of amps, can i use a car battery without damage to the engine, thanks again.

check the voltage in your battery packs to see if its where its supposed to be.

If its running 2 *7.2v batt then its running 14.4v assuming they are wired parell i use a car battery for my bump box,s and never had any problems

Thanks i'll give it a try, Tomahawk.

I use a homemade starter box with a airplane starter and 12 volt battery, it turns over the .39 engine i have fitted in the car i`m building, my friends starter runs with 2 7.2 volt nicads and a 540 motor and it just smokes and cant even move the engine.

Rick, thats what i'm talking about, i've been flying planes for a while and i've had some trouble starting those ABC type, my box does the same thing, just fries!!! I have some extra starters, maybe i'll try something like you have, how many amps does your battery have, My box has 14.4 volts-- Big Deal-- Give me the AMPS.... Thanks for your help..