carb or fuel pump

[barrie102]

You have to undo a nut inside carb to get to filter, Have you ?.

[cadetchris]

yep, had that off. as well as the whole fuel float and needle assembly in the reservoir, it was all in bits and the pipes where poked through with some wire just to make sure that their were no blockages

[bmcecosse]

Well - my apologies - you have the correct connection for the fuel. So - it's possible that the fuel level in the float chamber is much too low - you will need to find a way to raise it. To check the level - remove bell and piston so you can look down into the jet - with pump switched on you should see the petrol just about an 1/8" below the jet top. Other possibilities ....... any chance the needle is set too low in the piston (or jet set too high) - so it is completely blocking the jet when it's in the down position - not leaving an annular clearance ring for fuel to escape into the air stream ?

[cadetchris]

ill have a fiddle tomorrow afternoon when i get back from work and check those bits

[cadetchris]

well i am not at a complete utter loss as to why this carb isnt working. i have tweaked the float and that didnt do anything, i had a look for the gap between float and jet, and compared to the original carb, there is barely a whisper of difference (i tried a feeler guage and they where both the same)
so, i am at a loss as what it could be. its more of an annoyance than an inconvenience as its something i have bought, but it dosent work.

so, anyone else got any suggestions?

[barrie102]

Going back to an earlier post of yours you say you have no filter fitted. I find this bemusing because HIF38/44s have a filter under the needle valve seat. (mind you if that was blocked you wouldn't fill float chamber). all i can think is that you have needle and jet in a closed position. Try starting with the piston held up via lifting pin and see if engine runs, it won't need lifting much if it continues to run(which I hope it will) release the lifting pin and engine should stall(no fuel) if this is the case then your needle/ jet relationship is incorrect.
Needle position in piston should be checked and valve seat position (via adjusting screw) lower fuel inlet side of carb.

[AlMcL]

Just had a simillar problem with my standard carb engine would run for about five mins then stop, i would leave it for about an hour try to start it and pump would run like mad then engine would start.Found the fault with this by accident,I was about to take pump off for a new one when i checked the copper fuel line,the end that goes into pump was loose,not the nut but actual brass end that is braised onto pipe it was only loose a little but enough to cause pump not to supply enough fuel as it was also sucking air, as both engine and copper pipe got warm,just one to check may maynot help.

[kennatt]

there should'nt be a gap between the float and the jet,the float should be hard up against the jet when the bowl is full,or am I not understanding what you are describing.Been thinking about your fault and I think the only answewr is that the float level must be too low.The top of the level in the bowl has to be at the same height as the jet in the carb to hold fuel near to the bridge,otherwize the engine can't draw fuel in.Blowing down into the bowl would force the level in the bowl down thus raising the level in the jet letting the engine run.I would try filling the bowl manually so that you know it's full and see what hapens.Mind I'm not familiar with the layout of 44 carbs so could be way off the mark

[cadetchris]

stangely, when i was decanting some fuel from car into a fuel can for the lawn mower (connecting a pipe from pump outlet to can) i did notice an awful lot of bubbles in the fuel line, could this be a factor in the carb not running?

[AlMcL]

Just had a simillar problem with my standard carb engine would run for about five mins then stop, i would leave it for about an hour try to start it and pump would run like mad then engine would start.Found the fault with this by accident,I was about to take pump off for a new one when i checked the copper fuel line,the end that goes into pump was loose,not the nut but actual brass end that is braised onto pipe it was only loose a little but enough to cause pump not to supply enough fuel as it was also sucking air, as both engine and copper pipe got warm,just one to check may maynot help.

[cadetchris]

checked that a while ago,

[kennatt]

if the fuel level is correct and you have done as bm suggested ie looked at the jet with the piston removed and seen petrol at the head of the jet,and the needle is fitted corretly.then there is no other reason why the engine should not run.unless there is absolutly no compression and therefore no way of it drawing air and fuel into the cylinders.It Has to be that there is no fuel high enough in the jet assembly or the needle is too low and is shutting off the top of the jet, Blowing into the bowl would bypass all of these problems forcing petrol into the carb and alowing the engine to run.

[cadetchris]

well i did do as bm suggested, and i adjusted the float, by bending the float's metal strip that cust off the fuel. this didnt do alot to be honest, the fuel level didnt change within the jet.
i also thought the needle was stubbing out the jet, so i checked it and there was a very small gap between the float and the carb, which wasnt any bigger or smaller than the gap on the current carb.

safe to say, i am going to have one last fettle tomorrow and if that dosent cure it, then ill call it a day with this carb. its turning out to be alot more waste of time than i ever thought

[bmcecosse]

Sounds like there must be something major wrong with that carb - send it back fo ra refund!

[cadetchris]

i am seriously considering that, though it was an ebay find, so i am not to sire where i stand on that front

[kennatt]

if its within the time limits and you used credit card or paypal you may get a refund,maybe. Looks like you have checked everything,could be a faulty casting,maybe the bridge is to high ,or wrong float??.or has the float valve been packed out to lower it for some reason,thus preventing the right fuel level worth a check or wrong valve needle very curious

[cadetchris]

unfortunetly, its been over a month and a half since i bought the carb and according to ebay i cannot return it. which is a pain. so, i really need to get the level of the fuel to go up and check why the pump puts lots of bubbles in the fuel line.

right, off for a fettle

[bmcecosse]

There really can't be that much wrong with it - it's a very simple thing. I assume the piston rises and falls freely ? And it's definitely not a B prefix needle in a 90 thou jet ?? I've never had to meddle with the float etc on HIF carb - so can't help you there - but there is loads of advice/diagrams on internet.

[Kevin]

and check why the pump puts lots of bubbles in the fuel line.

You really need to sort this first before getting back to the carb.

[cadetchris]

its definitely an ADS needle, could it be the wrong jet? i assume that's ok as the other needle was something beginning with an "A" so i should be ok.
ill have a fettle with the pump and try and figure out why its giving me bubbly fuel. i think it might be owing to the inlet pipe not setting perfectly flush with the inlet on the pump, just a case of fettling really