FG Marder splutter on acceleration!! Help!!

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Stuie89

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I've recently brought an fg marder from eBay. Replaced some of the drive gears as they were faulty and hoped that would be all. But it will not hit top revs and speed. It seems to splutter and hesitate when accelerating. Even when holding a steady hf throttle it does it. I had the piston rings go on me so I've replaced with a cy big bore kit taking it up to 29cc but still the same problem. I'm beginning to lose the plot now as it seems to be getting worse. I'm used to nitro so 2 stroke petrol is new to me but I am
Beginning to regret getting it. It runs fine on tick over but will not run properly when accelerating. I noticed last night the yellow fuel pipe from the top of the carb goes down into the fuel, should this be out of the fuel as it is a breather? Would that make such a problem?? Anyone who can help I'd really appreciate it as I'm at my wits end! I can tell it's or potential but at the moment my wallet is gettin very light with so many repairs! Thanks, Stu
 
Sounds like it needs tuning.......
Make sure the air filter is clean - check inside, don't just rely on the outside condition. Also check the head bolts, bolts thru the carb (whilst you have the filter off!) and the exhaust manifold bolts are all tight. Your fuel should be mixed to a 25:1 ratio (200ml oil to 5L fuel, 40ml oil to 1L fuel or use a mixing bottle). The yellow fuel line is a return line BTW!

Follow this guide for all settings & info.......Reset the H & L needles to stock settings & start from there.

https://www.largescaleforums.com/showthread.php?t=2761

Let us know how you get on.
Add your location then maybe someone nearby can assist :D
 
Hi bud, first of all could you put your location on your profile as you may have a new mate down the road who could help you out but you'd never know.

A few things to check.

fuel pipes on the right way round, the bottom one goes to the clunk in the tank.

Make sure the low needle is wound out 1 1/4 turns out and the hi needle is 1 1/2 turns out - use this as a starting point

Check the plug condition

Check the air gap of your coil - slacken the bolts that hold it on, insert an FG header card, press the module down then tighten the bolts.

This should keep you going.
 
Hi guys thanks for your replies. I've now put my location on my profile, I live in Gloucester in England. I have checked all gaskets and air filter is clean. I checked the air gap on the coil when changing head and set it to the size of a busines card. Something doesn't seem to be right as the idle speed screw has to be wound right in for it to start. Is this normal? I have the h & l needles set at factory settings. It seems to be better when running cold but when it warms up it gets worse. I couldn't even drive it last night it was soooo annoying! Could it be a problem with the coil or are they either working or not? Thanks, Stu
 
Sounds like an air leak mate. When the engine warms up the casting will expand and possibly open up the leak & make it worse. Methodically spray WD40 on the joints round the engine & carb & listen for the engine note changing. The revs should drop when you find the leak as you are plugging the hole with the WD40 and effectively richening the mixture. Make note of where the leak is & check the gasket is seated properly or replace if required.
 
Sorted it! Thanks allot for your replies guys! Turned out to be the breather pipe was pushed too far into the tank, have pulled it out so that it's only just in the tank and it's sorted now. Having not none what the pipe was for I assumed was meant to be that way. Im really pleased with my purchase now! I don't have a manual, does anyone know where i can download the complete manual you'd get when brought new? I've only found parts diagrams and lists. Thanks again for your help! Stu
 
I meant return line from the carb, the pipe that comes out by the priming bulb. This was pushed inside the tank right down to the bottom so that the end was always submersed in the fuel.
 
I don't have a manual, does anyone know where i can download the complete manual you'd get when brought new? I've only found parts diagrams and lists. Thanks again for your help! Stu[/QUOTE]

Hi
Not sure you would need much more than that. I get all my info of the FG site. Plenty of info in downloadable form on there. Exploded diagrams for all cars and parts + engine information and explanations for tuning. If I remember correctly some information is also available at RC Car Online. Glad to hear you got things going again.
 
i have a breather pipe on mine. Ive got two pipes for the carb and two that join together with a Y connector that vent the tank. After looking about online i found its from a carson or a touring car. don't you need a breather on the propper marder tanks?
 
There are a breather cap fitted. Small hole on top of the cap with a rubber fixture and filter inside that let's it breath but keeps filth out.
 
the caps are vented but better to run the breather tubes, even the leo comes factory with these and they are the flagship model! if you got them keep them, better than standard plumbing.
 
you are better off with the breather pipes as you've got than just a 1 way valve in the cap. you don't need a filter on the end of the pipe, mine runs along the roll cage to the back of the car and slots into a 'p' clip screwed onto the back bumper.
 
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