Anyone shed some light please

[K88MUD]

Could do with a few ideas guys please.......

As some of you might remember i bought a secondhand FG Marder in a box and some of the bits were missing.....i converted it to a half monster beetle.

Now my problem lies with it running when its warm.....it can be a bit of a pig to start but it always does after a bit of a fight......it runs quite well after that with good throttle response but sometimes bogs......after about 5mins just quick bursts up the street after returning the throttle back to idle it just cuts out as if its out of fuel, and then its a pain in the bum to restart unless you give it full throttle.....even then if i play with the throttle its very hard to keep it running.

Now i have a few ideas as to what might be causing this.....there is a fair amount of play in the carb throttle shaft, always seams to have air in the fuel lines.

Could these be the problem or is there something else im missing ?

 

[charlieboy]

Could do with a few ideas guys please.......

As some of you might remember i bought a secondhand FG Marder in a box and some of the bits were missing.....i converted it to a half monster beetle.

Now my problem lies with it running when its warm.....it can be a bit of a pig to start but it always does after a bit of a fight......it runs quite well after that with good throttle response but sometimes bogs......after about 5mins just quick bursts up the street after returning the throttle back to idle it just cuts out as if its out of fuel, and then its a pain in the bum to restart unless you give it full throttle.....even then if i play with the throttle its very hard to keep it running.

Now i have a few ideas as to what might be causing this.....there is a fair amount of play in the carb throttle shaft, always seams to have air in the fuel lines.

Could these be the problem or is there something else im missing ?

new carb in order mate there shouldn't be any play in the shaft, try tightenin the bubble screws aswell mine came loose and caused it to cut out!!!

 

[PhattKatt]

Check the fuel lines for cracks. Replace the carb; probably a diaphragm problem.

 

[dwarfy]

Bogging when running usually means its running too rich if I am not mistaken. The cutting out at idle then trouble starting could mean its out of air and not out of fuel ie flooded. What colour is the plug? Full throttle lets more air into the mix & makes a flooded engine easier to start

 

[Timmahh]

air in the carb line (not the return line ) is a key problem needing to be solved. if air is getting into the intake fuel line, then its leaning out (more air than it should have) this can also cause the stalls, hard starts and other issues, including leaning out too much and possibly lean siezing the topend.

i would replace all the fuel line with New Tygon line, don't use nitro fuel line as it is no Gasoline approved, it will swell. Tygon is Gas approved and works great.

a loose throtle shaft can allow are to be sucked in, further causing it to run lean.

bogging can be a sign of rich or lean. the bog varrys a bit between them,and is usually noticable by sound. if it sound crackly or like its gargleing, its rich, if it sounds like its straining to get out of the way of itself it could be lean


a worn ring can also produce those same symptoms. to check if its time for a new ring or maybe a new topend, the next time its hot and wont start right back up, before you do anything else, pour a table spoon of strait 2stroke oil thru the plug hole. roll the rig around so the oil coats the entire piston and ring. then put the plug back in and try to see if it starts as you expect it normally would.

if it does start back up as you expect it should normally, then the ring is worn and needs replaced, or the topend may need to be replaced.

 

[sperera]

yeah id have to say try a new carb, might as well repalce the lines while your doing it. Make sure you use factory needle settings and tune from there if needed.

 

[K88MUD]

Thanks guys......lots to do now.....will let you know how it goes

 

[sprocket]

sorry for sticking my nose in here but what engine is in it ie petrol or notro not familiar with these??
if it's two stroke gas (whipper snopper )adjust your low end until you have a good responce in the transition and then high end after.

nitro adjust low end ...could be lean especially if it's hard to start again,ritch will run with glow whereas lean won't

hope this helps there is a lot more tricks if it is gas

cheers Ian:2guns: