Once warmed up full throttle to idle trucks dies and bogs

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B

Bondslayer

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It was 70 degrees here n dallas today. Warmed the truck up runs great!!!! About 10 min into driving I noticed WOT was bogging a tad at mid power range. When letting off throttle to a cruise and truck at low speed when I gave it gas it would want to die unless I feathered the throttle but then had the bog. Truck died a few times from scenario mentioned but would start again with just one pull. I'm wondering if the carb is a tad to lean? I'm used to tuning my 1/10 scale and the carb on this Trevor Simpson motor I'm not familiar with adjusting. Is this a rich or lean condition, how can I determine ( pull spark plug?) which need to I adjust, high or low. To much invested in this motor to just guess and turn screws. Any and all info would be appreciated!

Burn out marks with the street tires I put on instead of ruining the knobby dirt tires!
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im guessing too lean dude especially running in that heat, wanna richen it up a little to help with the cooling :)

as for which needle, if its bogging above half throttle then richen the H needle, below half richen the L needle :)

only turn them slightly no more than a tick each time, if it goes worse then go back a tick :)
 
There's LOADS that's been written on this subject.
Check out the Sticky in the Engine section regarding tuning.

LargeScale is the opposite to Nitro - adjust the LOW before the HIGH.
If the needle's / carb are in good condition, better reset to 'factory default' of 1 1/4 / 1 3/8 LOW / HIGH and take it from there.

It's probably a fuel setting problem as Daz has mentioned.
Is the filter nice and clean?
Is the plug new / old / sparking well?
Al.
 
Filter is nice and clean and has the outerwear. I'll pull the plug and check. The gallon of 93 octane I bought is maybe 3 weeks old. It runs fine until warmed up. Good to know about the sticky and that tuning is opposite of nitro!
 
Check your fuel cap make sure your breather is working properly,if not will also make it bog after running for a few,gets pressure in the fuel tank and restricts fuel from flowing to the carb.
 
whittron said:
Check your fuel cap make sure your breather is working properly,if not will also make it bog after running for a few,gets pressure in the fuel tank and restricts fuel from flowing to the carb.
Click to expand...

Agreed!

He means put a new ring on the piston. But I would check your tune like stated above, check your spark plug (you want a nice brown paper bag color) also check for a gasket leak. Carb, intake, head, crank case and exhaust. Make sure there is no wetness.
 
Hope that Trevor Simpson motor with 4 hours on it isn't already jacked. This was the warmest weather I drove it in. In 30 degrees it was fine
 
I'll check it today. I had driven it hard for a good 20 min maybe the motor was getting heat soaked. Since it dies and bogs when coming off throttle to cruise and then I give throttle is it bogs so that makes me believe the L needle. Twist screw out to richen correct ?
 
Plug color is more of a grey color, I think it's to lean. Will adjust the screw here in a bit and see how she reacts.
 
Light grey? Agreed.
Mid-Dark grey with hint of brown? Nothing wrong with that.

How full was the primer bubble when you'd finished the 20 minutes' bashing - FULL, 3/4, 1/2?
This is a (VERY ROUGH) indication of the settings as well - read other threads on the subject.

I've had to considerably RICHEN the high speed as it was bogging on full throttle / higher revs - and it's much better, but I'm only adjusting very little at a time. I know it's a new engine, near enough, so the full throttle was for a very short time, once warmed up, on the third tank.

Al.
 
Richened low and high speed need 1/16 a turn and perfect. Ran for about 30 min and never lost power. At first truck would only idle and die after 30 seconds of idling. If I tried to give it any gas it would die. Richened low needle and was able to rev and from a hard rev tk coast truck would die. Richened high needle and no problems at all!
 
atom3624 said:
Light grey? Agreed.
Mid-Dark grey with hint of brown? Nothing wrong with that.

How full was the primer bubble when you'd finished the 20 minutes' bashing - FULL, 3/4, 1/2?
This is a (VERY ROUGH) indication of the settings as well - read other threads on the subject.

I've had to considerably RICHEN the high speed as it was bogging on full throttle / higher revs - and it's much better, but I'm only adjusting very little at a time. I know it's a new engine, near enough, so the full throttle was for a very short time, once warmed up, on the third tank.

Al.
Click to expand...

Primer bubble I just checked and is 90% full. Upon richening the low speed needle I did notice more exhaust smoke, this went away as truck warned up and only at full throttle would I notice a small smoke trail which I thought meant good. The neighbors don't like me at all!
 
Sounds like it's running well.

I've had similar 'problems' with my TS in same state - new, running in - but it's been running, just bogging on acceleration.

I was thrown by some old fuel simply having a lot of oil in it - petrol evaporates more quickly.

Fresh mixed fuel and richened settings, and it seems well.
I'm on about 1.3 / 1.5 LOW/HIGH on a Walbro 813.

I still want mine a little rich, and don't want to be full bore too soon. It is revving freely and running well.

Al.
 
I don't know what carb is on the truck, as far as I can tell nothing is factory motor/trans/exhaust wise. Turtle racing, Trevor Simpson motor, forgot name of pipe.
 
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