My son has a 1985 honda 250 trx fourtrax. problem is getting it started and then trying to get it to idle. If you find just the right spot on the throttle it will start with electric start. but most of the time you can use the kick start with throttle and it will start up. Is this a carb problem or a firing problem? runs fine after its started, also starts fine after being run a while.
And can some one tell me where pick up coil is located, have a 1986 for parts, was going to change that out to see if it makes a difference.
Im lost here people, any help will be appreciated.

 

first i would check the spark pull the plug ground it to the engine use the starter and see if you have a nice fat blue spark might have to do it in the shade or dark room
oh yes try not to shock yorself

if its good i would suggest the carb if you have a book find where the float should be set maybe its not letting enough fuel hence the need for throttle. just my 2cents and your son has a nice quad i had one and loved it.it was a tank.

 

Hey man thanks for the reply, I have pulled the plug and have lots of spark cant tell you its a fat spark but you can see it in the daylight, and you are right it is a tank, gave 300.00 for it last summer and this is the first real trouble we have had, can you tell me, does the motor still rely on spark once its started, cause once its going it runs fine except for idle. Thanks again

 

yes that spark keeps the engine running it will spark once a revolution if the engine is running at say 5500rpm you are getting 5500 sparks a minute so yes it does rely on it

and a dumb question have you tried the idle screw

 

yeah i have tried thr idle screw no help at all, the reason i ask about the spark is because of thr way it runs once its running, so as it revs the greater the spark, could the spark be getting so weak at a low rev that it wont keep it running? the reason i keep going back to the spark is that it happenend so sudden, say after runing thru a good hole of water wide *** open. wasnt the boy, was a stupid adult! have checked air filter and all thats obvious to me.

 

if it was right after the body of water just for the heck of it i would start off new take the plug out and get a new one ngk sells them for like 3 bucks and it definitly wont hurt your engine iwould also check your plug cap if it looks corroded at all scrape it clean and if you want to simply try the ignition coil follow the spark plug cable to the little black box and thats your ignition coil but i dont believe thats it because you tested it and it was ok oh and if you dont want a new plug make sure yours is gapped right and its not fouled but if it was me i would just go get a new one

 

Well I have done all that even took the ignition coil off the 86 I have here for parts, new ngk plug,no help. what about the pick up coil or cdi box could either of those be the problem and where are they located? or are you still leaning toward the carb?

 

Have found pick up coil and cdi box their right in front kinda under headlight, changed the pick up before it got dark could certainly tell its running stronger even got it to idle for about 5 seconds, what the heck, will change cdi tomorrow may help even more, again thanks for the input.

 

thats great hope you get it going sorry i couldnt be more help but good luck

 

you may have fixed it already, but here goes, is it a 4 stoke or 2 stroke engine. if it's a 2 stroke engine you may have crank seal problems or reed valve problems. i only suggest this becouse i have run accross this in snowmobile's. the pressure in the crankcase may be blowing past the seals or reed valve's. just a thought