kart engine only runs at full choke??

[Benjo]

i have a quad engine on my kart and its got a mikuni diaphragm card, it will only run at full choke.
I'm running it with a pod filter not the stock air box.
Would it help if i were to re-jet or adjust the full needle?

 

[fowler]

i think the pod filter is making it run lean.
but saying that u always had a pod filter on so is this a recent thing
(assuming this is the 280 offroad shifter)

 

[Benjo]

yea it the shifter. Could a dirty carb be my problem, its not that dirty but it wouldn't hurt to give it a clean.

 

[fowler]

yeah would be crap in the jet
how are the gaskets while u are there
i am assuming this was not a new bike and has never had the gaskets changed

 

[Benjo]

gaskets are good and jet is clean, jet was the first thing i checked.

 

[fowler]

fuel line blocked?
vacume leak in clyender or head gasket ?

i dont know just puting ideas out there

 

[Benjo]

i don't think i have a vacuum leak, why would that cause my problems?

I've got good fuel flow. I'll give the carb a clean and play around with the fuel needle, i might have it set at the wrong height last time i had it apart.

 

[fowler]

a vacum leak means on the drawing stroke of the piston it draws in some from out side rather than from the vaules

yeah try the needle

 

[brendonv]

If it only runs on choke it means its getting to much air or not enough fuel (needs larger jet or jets need cleaning) or there is an air leak elsewhere (gaskets).

 

[KieranM]

if you removed the carb, bare in mind that if the gaskets had become stiff the wont seal as easily when you go to replace the carb and may let air escape, as a result the engine will try to suck in the air that may be coming through the gasket and cause it to have too much air in relation to the gas/petrol.

 

[fowler]

thats what i said

 

[Benjo]

i adjusted the the needle and it ran, took it for a ride and it kept spluttering and died a couple of times. I haven't cleaned the carb yet and i think that it is just my jet getting blocked. I'll give it a clean and get back to you.

 

[fowler]

might wanta clean the tank while u are there

 

[Benjo]

yea I'm also gonna install a fuel filter.

 

[fowler]

 

[KieranM]

thats what i said

****, sorry didnt see your post

yea fuel filter is a must

 

[mike75925]

check your boot between the engine and carb. the rubber ones like going out whenever. sometimes you can seal it over with a bit of silicone gasket maker. if your idle jet is clear, the boot is good. remove the mix screw and blow through with compressed air. could also be low compression.

 

[Benjo]

just pulled the carb apart and found that the rubber diaphragm didn't quite fit properly, it was a bit stretched. I'm going to get a new one when i get a fuel filter

 

[mike75925]

before replacing the slide diaphragm, make sure it has at least one big hole. the diaphragms can be 'oversized' due to fuel or carb cleaner. they can be a pain to reinstall, but will still work. if the hole or holes are small enough, most times you can use automotive silicon to reseal it. this is for pinholes only. if your holes are bigger, replacement is required.

 

[Benjo]

When I put the carb together found that the the diaphragm fitted, I guess the carb cleaner messed with it.
I also added my new fuel filter into the fuel line and the kart runs great now.

I guess my problem was a combination of a dirty carb and bad fuel needle position.


Thanks for all of the help and useful advise