Abnormal High fuel consumption - Suggestions?

[wildcat71]

Hi folks, finally today i tested my "new" used marder with a ported 30.5 and a WT813. Well i am not so sure about the carb as i read that the 813 has an accel. pump but no choke lever. My carb has an external pump but has a choke lever too.


Anyway.... it is a beast, impressive! but its consumption is impressive too. In about less than 10 minutes i burned almost all the fuel thank and it was very full!

I read around all the forums that a tank should lasts about 30-40 minutes but this beast drinks like me in a pub!

Is the carb setting toooooo rich or is it normal for a 30.5 cc and (maybe) a wt813 to drink like that?

Should i reset the carb setting?

Thanks for your replies

Ricky

 

[dwarfy]

Even running rich that is going some :no:
I would say its more likely to be a leak. Check these:
fuel lines for splits & make sure they are connected properly
that the tank is good, no cracks on the joints esp around the filler
check filler cap itself for fit or crossed threads

When you have run the car the filler cap tends to be under vacuum, ie when you unscrew it you will hear a slight hissing as the pressure levels out again. If you run it for 5mins then check this it will give you an indication as to whether the system is sound. I doubt it will be!

 

[voo2doo]

If your getting 10 mins out of a tank there is something seriously wrong.One of the lads I run with has a 30cc and he gets 40 mins out of it .I run an MCD with a 26cc,ish with an 813 and I could get 35-40 out of a tank and I don't baby my cars either.
J.

 

[zouz10]

How are you running it? Are you WOT or taking it easy. If you are taking it easy it will last a while. WOT you will burn it up in 25-30min.

Also, i know this may sound silly, but fill it up again and run it till the car stops with absolutely no fuel in the tank anymore. Make sure to time it on a watch, and see. Sometimes i get so carried away having fun that the time just goes by quicker than i thought.


Chris

 

[slawhammer]

you could have a air leak..or maybe the 813 carb is bad....There not woth fixing...
I think you also need to look at your spark plug for color...you want to see a nice
light brown color.....Try your carb settings at...H 1 1/2 out L.1 that should be close.
Just my opions here..Slawhammer

 

[wildcat71]

thanks for all your replies!


first of all i unmounted the carb and the fuel tank. Cleaned the carb and found that it is a 668A walbro but there is also a piece between the carb and the cylinder where it is attached the pump. I changed the whole tank, tubes, fuel filter with newer one surely not broken. Tomorrow i will try to rebuild it and have a new test.

Not yet checked the spark color.

About the time...well...i will take a look at the time because in effect i was having so much fun that time was flying away and maybe 30 minutes seemed to me as 5

Keep you updated...

Thanks

Ricky

 

[slawhammer]

The block between the carb & cylinder is a isolator block or intake block....
the plastic blockes are known for problems....which cause's air leaks.....
invest in a alloy intake block with teflon gaskets.........Now use new gaskets when
you put it back together...watch out for the small hole on the bottom..don't block that hole....that hole is the pulse...that is used to make the diaphram in the carb work to
bring the gas from the fuel tank....do not over tighten the bolts...that can warp the block..which will pull away from the cylinder..thus causing a air leak........
there is a torque value on those bolts..think 35 inch pounds......all bolts on the engine have a torque value......But the carb can be worn internal....there now worth trying to fix..just buy a new carb..you will be better off.......Hope all this helps...Slawhammer

 

[wildcat71]

Thank you Slawhammer for your suggestions.

My isolator is mado of plastic, i will buy a new one asap.

At this time i could have more options so i ask for your help again

1. buy a new intake block but i can't find a shop where to buy an alloy version. I found this but i think it is in plastic, isn't it? It has a drilled hole where i can connect my vacuum pump. Do you know where can i buy an alloy intake block?

2. buy a bolt on reed kit to be used with my wt668 carb

3. buy a 813 carb and alloy intake block

Do you think that a bolt on reed kit is a waste of money for a normal (read "bashing") use and not for racing?

Which one of the options above would give me the best performance/price ratio?

In the weekend i will test the beast again with the new fuel tubes, tank an gaskets all around and see if something changes.


Thanks
Ricky

 

[slawhammer]

On-line hobby shops or Rc Suppliers...most will carry a alloy intake block...
Bolt on read valve is a waste of money unless tou have the ported head kit to match the use of the read box.....I would opt to buy another new 668 carb....
I wouls suggest for the money right now is to get a alloy intake & new carb & go from there.......Slawhammer