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Revo 3.3 has low end bog

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B

bmessy

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I'm having a low end bogging problem with my 3.3 revo,i went back to factory settings for the fuel/air,,still bogs,it is most apparent when car is warmed up.i dont know what to do,once its out of the boggy low end it seems to run fine ,its a lil to rich but i can deal with that once i get the low end problem figured out or maybe its related idk lol please help:D
 
Factory settings for the Revo would have you a little on the rich side. If you're bogging down and have to 'blip' the throttle to get it up and running, I would suggest leaning out the LSN, only a 1/16 of a turn at a time. Small adjustments can make a big difference, you can also give it the 'pinch test'. Make a couple of WOT passes and bring it in, pinch the fuel line and start counting. The engine should rev up a little and then die, somewhere between 3-5 seconds. Any less = too lean, any more = too rich (on the LSN)
I would also highly recommend a temp gun, you can get one on ebay for $25 and it can add considerable life to your motor.
 
@MrClean I've got the temp gun ,ill try the stall test bliping the throttle doesn't help,from idle i pull the trigger it slowly moves all bogy then all the sudden it takes off like it should.

ill try leaning out yhe LSN a lil thats a good tip too ty
 
ok,I've leaned it maybe i need to go further on the lean side ,when the car is cold it runs great once she warmes up i hold it at WOT and it hardly moves,also i dont see any smoke from being to rich when its warm but when still cold i do,I'm on vacation right now and left my temp gauge at home,,i tried the stall test the engine didnt rise in rpm like you said it should,,i also like to say thanxs to woodie for founding this site its the best I've found so far and I've gotten lots of help from it
 
check the glow plug, may want to try another glow plug, and make sure the at filter is clean. Tuning the carb is a must. Too rich can definitely cause bogging.
 
You need to start leaning out the LSN. Have the engine warmed up, lean it about 1/16 of a turn in, drive it away from you, return it and lean it a hair more. Keep doing that till you get good clean take off from a dead stop. When that's done, go for WOT and do the same for the HSN.
 
Rolex said:
You need to start leaning out the LSN. Have the engine warmed up, lean it about 1/16 of a turn in, drive it away from you, return it and lean it a hair more. Keep doing that till you get good clean take off from a dead stop. When that's done, go for WOT and do the same for the HSN.
Click to expand...

I'm a noob at this and trying to learn, but isn't the process supposed to go the other way around?

I was under the impression that you first set the HSN and once that was set and good, you then worked on the LSN to adjust the takeoff. Have I misunderstood?
 
This is where it gets tricky, what Rolex is describing is advanced tuning.
However the 3.3 is one of the few engines i have encountered that when you adjust the HSN, it greatly affects the bottom end. You will actually here the idle speed increase.
Follow the instructions, just make smalll adjustments. Also you may need to start with the HSN a bit richer than the factory setting.
Rolex is right though, you adjust the HSN to the type of driving you are doing. Lots of WOT= you need a richer HSN setting. Short bursts of acceleration you can run a leaner HSN setting.
Also the traxxas factory clutches engage way too early, which can cause tuning issues such as bogging.
Listen to the engine and forget the factory settings... I had to run my 3.3 richer than factory settings due to my air filter/pipe selection.
 
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I've had the same problem with my nitro. I think its from the engine being run too lean. It runs nice when cold but because it is too lean it heats up too much and then bogs down. I think its an over heating problem. Make it rich and then lean it out untill it bogs again (only 1/8 a turn at a time) and then richen it till you get the perfect performance.
 
is it bogging, or starving for fuel? If you are seeing no smoke my guess is you are too lean on the lsn. Knowing the engine temps when you are having the problem would help us help you diagnose the problem.
 
yea got to keep those temp guns with the truck at all times! The wife and I are on vacation too and due to the geograpic change her truck was over heating bad and we had to retune it.
 
One more important note...DO NOT change any carb settings until the engine is warmed up. Every time you run it, it will be warm, so that's where the settings have to be made.
 
If no temp gun is available you can always try the spit test... Warm your engine up first... put a drop of spit on the head, if it sizzles right away it's too hot. It should take like 3-5 seconds to evaporate (if memory surves)
 

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