Cutting out after a quarter tank used

[Philthy]

I have a consistant problem where my engine will start fine from cold, run like a champ and then after a quarter of the tank is used itll cut out.

 

Have to let it sit for minimum 15 minutes before itll consider starting again.

 

Sometimes topping up the tank to full again will shorten this process.

 

Im thinking at has something to do with the fuel system but dont know where to start.

 

Any ideas?

 

 

[mikelloay08]

might be to lean.

[Thunderwolf]

how old is the engine?

 

there are 3 possibilities here.

 

1. your engine is too lean, it getting too hot and shutting off because the fuel is vapourizing before it is meant to, could also be causing alot of wear on the parts

 

2. your engine is coming to the end of its life, as the piston and liner expand from the heat the compression drops abit, normaly this is fine and the engine can handle it but as it gets used and worn this compression drop gets bigger, eventually the compression drops so much that it can no longer burn the fuel and so it dies. once the engine cools down you have compression again which is why it can start up

 

3. pressure line from exhaust to fuel tank is blocked, as the fuel is used a vacuum forms until the engine can't pull fuel any longer and so cuts out, the clue with this is the engine often leans out slowly which can end up disguising it as option 1 above.

 

 

given what you have said i would say number 1 is most likely, easy way to tell is to return thecarb/needle setting to factory/break in, this will at least rule out one of the above options

[Philthy]

Great post Thunderwolf thank you

 

I will try richen it out and see how that goes. It does have a nice steam of smoke under acceleration at the moment though.

[Nitroholic]

Smoke is not a reliable measure of temperature, as the amount of smoke can vary HUGELY depending on the oil content of the fuel you are burning.

 

Modeltechnics basic blend has about 16% oil. Same with Optifuel RTR blend ( also sold branded as HPI Power Fuel ). These make MASSIVE smoke clouds, and can be very smokey even when very lean.

 

Byrons, ModelTehcnics BingBang or Optifuel Race blend have around 9% oil, and are a lot less smokey.

 

Thunderwold has pretty much covered the options for your problem. Might be worth investing in an IR thermometer to check your temperatures if you are not sure.