Engine dies while refueling then....
 

Hey nitro gurus. .21 Maxys Cinco engine in Gt8. After warming up for the race, I come in to top off and I cringe at that thought. Due to the fact that there are not many nitro guys at our track, I usually have to run down and top off due to no pit guys...as the tank get full, I can hear the rpms sag, then once I close the lid, it really sags, then dies. Now the fun part...getting it restarted...it takes quite a while before I can get it re-fired....

My question is, what adjustments do I need to make? Obviously, I have it tuned for what feels good on the track, I try to keep it revved up as much as I can in the time that both hands aren't fueling the car. Thanks in advance.

sounds like its loading up it sounds like it might be rich does it run on after running down the back straight?(high rpm) then slow to idle down would give you a clue

a little bit, yeah. I won't say that it is ramped up too much, just a little elevated. You mean hsn or lsn?

Sounds like your idle is too low. Turn your idle up a hour or two. Let me ask this, "How does your glow plug look?" Is the current glow plug new in your engine head? If you pull the plug and it is grayish in color, you are running too lean and if it is blackish in color, you are too rich. Sometimes your idle could be good but your plug may not be. Just a couple of extra things to check and think about......

Thanks Jlock. Will check color later. The plug is 2 race weekends old. I put the current plug in because the previous plug began wanting to die once the glow driver was removed. This engine runs great, but the tuning window is rather small. Haha. FWIW, running a Nova C7TGF in it.

Depending on your nitro content, you may want to run a hotter plug. I don't know where in the range the Nova plug you are using (as each manufacturers' plugs are numbered different for their ranges). So many little things that will drive you nuts at times trying to figure which is the fix..........

not familiar with that engines but i believe they recommend a 6 but still i would verify that it is not too rich on the LSN i would pinch test it to verify this of course assumes that the HSN is close and engine is running at a proper operating temps

Does it struggle to start because it's hot or is it too rich, the latter will puff a lot of fuel when it does start. Depending on carby, the more idle you give it, the richer it will get, I'd add few blades of idle CW and the same to LSN. The idle should rise, if it doesn't you're a little off tune...

There is a thread called the tuning bible in the nitro onroad engines thread. That article/post really helped me tune my engines. Im still new at it, but 90% of the time I can get it right.
Its a little different with nitro sedan because clutch and 2 speed will affect tune.

When the engine is pretty warm and you add cold fuel , it will always drop the idle and in many cases cause the engine to die. I started leaving my fuel bottle out in the sun before I pit and with the fuel warmed , it doesn't drop off the way it used to. Just another thing to think about and drive yourself crazy.

Engine Is to Rich

post pics of where your needles are at. When you and Marcus were battling and his car flamed out i had the LSN way too lean and upper too rich so after the pit as soon as he got on the gas it flamed out.

Depend the fuel used and % is diferent Needle position.
On road GT with 25% Maxy's Fuel in top is 3 turn open and low 4 1/2 open.
Temperature 250-260F

Using Merlin 25%

Yes Marcus, that's what it's acting like. Will check that out.