Air intrusion
#1

I just want to make sure if this sounds like any kind of air intrusion that’s causing my issue. I have a second hand revo 3.3 and it’s honestly been a pain. I bought it years ago and tried to tune it but never got it running very well so I put it on the shelf for another day. 4 years later I got it back out after having fun with my electric savage to see if I can get the revo working. Couldn’t get it to hold a tune so after some research I replaced the bearings in the engine, both front and back bearings. I got it started with a brand new glow plug but then that plug died on me and didn’t start back up. I just bought some new fuel today and after using a new glow plug and using a separate glow igniter I got the revo to idle and it was spitting a lot of fuel out the exhaust but it barely moved. The problem I had though is adding any kind of throttle to it would bog it down and kill the engine. I reset the lsd and hsd needles to what I heard was factory (about 4 full turns on hsd and flush with the lsd) and it idles but doesn’t want throttle. I lifted it up and let it free run in the air and same thing. It would spin the wheels on its own with no throttle added but as soon as I added any throttle it would bog. I gave it more and more fuel with the hsd and I noticed that the throttle would get faster and wheels would spin faster when suspended in the air but still doesn’t want throttle and will bog and die. I went through a tank and half like this not getting any clear result. I did read about air intrusion so I’m going to get some rtv to use around the carb, some on the engine backplate and get some thread sealant for the high speed screw. I heard the fuel line might also do it too. There is a weird thing about lots of smoke coming out of the fuel tank too while it’s running. Could the seal on the lid also cause this? Is there anything else I can look at or do about this?
#2

If the fuel tank is close and you see smoke coming out of it, then yes that is your problem. the rubber on the lid is probably hard and not providing a proper seal or the tank is just damaged.. I would make sure fuel and pressure lines are connected properly, if they are spray some WD40 on the rubber seal to give it some life, see if that solves your problem, and then order a new tank
#3

I just want to make sure if this sounds like any kind of air intrusion that’s causing my issue. I have a second hand revo 3.3 and it’s honestly been a pain. I bought it years ago and tried to tune it but never got it running very well so I put it on the shelf for another day. 4 years later I got it back out after having fun with my electric savage to see if I can get the revo working. Couldn’t get it to hold a tune so after some research I replaced the bearings in the engine, both front and back bearings. I got it started with a brand new glow plug but then that plug died on me and didn’t start back up. I just bought some new fuel today and after using a new glow plug and using a separate glow igniter I got the revo to idle and it was spitting a lot of fuel out the exhaust but it barely moved. The problem I had though is adding any kind of throttle to it would bog it down and kill the engine. I reset the lsd and hsd needles to what I heard was factory (about 4 full turns on hsd and flush with the lsd) and it idles but doesn’t want throttle. I lifted it up and let it free run in the air and same thing. It would spin the wheels on its own with no throttle added but as soon as I added any throttle it would bog. I gave it more and more fuel with the hsd and I noticed that the throttle would get faster and wheels would spin faster when suspended in the air but still doesn’t want throttle and will bog and die. I went through a tank and half like this not getting any clear result. I did read about air intrusion so I’m going to get some rtv to use around the carb, some on the engine backplate and get some thread sealant for the high speed screw. I heard the fuel line might also do it too. There is a weird thing about lots of smoke coming out of the fuel tank too while it’s running. Could the seal on the lid also cause this? Is there anything else I can look at or do about this?
Last edited by 1995 Monster T; 05-22-2023 at 07:05 AM.
#4

If the fuel tank is close and you see smoke coming out of it, then yes that is your problem. the rubber on the lid is probably hard and not providing a proper seal or the tank is just damaged.. I would make sure fuel and pressure lines are connected properly, if they are spray some WD40 on the rubber seal to give it some life, see if that solves your problem, and then order a new tank
#5

First the Correct factory settings are High 4 turns out +1/2 turn recommended. AS 4 turns out is the minim you can turn in If the engine is good it will run on 4-1/2 turns out and you can adjust to max speed. Low needle is flush inside needle to barrel or .24 measured from the top of the ball lever with a caliper. Idle is .05 mm. If you see smoke coming from tank lid replace seal. If you see any fuel around the motor on the chassis, you may or have a leak. But you replaced the bearings so you shouldn't have that problem. Depending on how old and worn engine is I suggest 18% oil lube fuel. If you can turn the motor over with plug in easy by hand. you may have to replace the piston and sleeve as it is worn out and engine will not run once up to temp. It will shut off.
thank you for the advice!
#6

First the Correct factory settings are High 4 turns out +1/2 turn recommended. AS 4 turns out is the minim you can turn in If the engine is good it will run on 4-1/2 turns out and you can adjust to max speed. Low needle is flush inside needle to barrel or .24 measured from the top of the ball lever with a caliper. Idle is .05 mm. If you see smoke coming from tank lid replace seal. If you see any fuel around the motor on the chassis, you may or have a leak. But you replaced the bearings so you shouldn't have that problem. Depending on how old and worn engine is I suggest 18% oil lube fuel. If you can turn the motor over with plug in easy by hand. you may have to replace the piston and sleeve as it is worn out and engine will not run once up to temp. It will shut off.
Also 0.05mm idle gap??????
#7

I’ll have to readjust the settings to try it again. I believe I did get it to almost 4.5 turns out and it ran decent in the air with no resistance but as soon as I touched throttle then it would bog. I am worried about the wear on the engine though. It has some pitting on the top of the piston and head so I’m sure it’s run too lean for quite a while. I will try spinning the motor by hand and see how easy it might spin over. If it is too worn out then I’ll invest into either a new piston and sleeve or might even think about engine swap.
thank you for the advice!
thank you for the advice!
#8
Tech Adept

do not use 18% oil fuel.
Pick a good brand that has good rep history in making fuel. VP etc
a quality oil package is the important part.
p.s ignore 1995 Monster T
Pick a good brand that has good rep history in making fuel. VP etc
a quality oil package is the important part.
p.s ignore 1995 Monster T
#9

I do 100% in all my 10 t Maxx's Itt runs fine. I run it in1/8 buggy's Heli's and boats for 30 + yrs. Stay away from fuel with less than 14% oil lube. Fuel with more oil protect the engine better and it will last longer! Buy fuel local. I run Omega.
Last edited by 1995 Monster T; 05-24-2023 at 05:36 AM.
#10

If people need to stay away from less than 14% oil then you are on the wrong forum. Let me remind you this is in the basic a racers forum and most of us are aware of oil contents and also what issues you can have with too much oil.
#11
Tech Adept

Fuel with more oil does not "protect the engine better"
A good quality Oil package will always protect better.
You are missing out on alot of performance and tunability... without any less engine life.
Im guessing you have your Idle cranked, LSN rich as and HSN lean as.
I have several 3.3 engines that ive had for many many years. They all run great and keep on trucking.(for relevence sake)
A good quality Oil package will always protect better.
You are missing out on alot of performance and tunability... without any less engine life.
Im guessing you have your Idle cranked, LSN rich as and HSN lean as.
I have several 3.3 engines that ive had for many many years. They all run great and keep on trucking.(for relevence sake)
#12

Fuel with more oil does not "protect the engine better"
A good quality Oil package will always protect better.
You are missing out on alot of performance and tunability... without any less engine life.
Im guessing you have your Idle cranked, LSN rich as and HSN lean as.
I have several 3.3 engines that ive had for many many years. They all run great and keep on trucking.(for relevence sake)
A good quality Oil package will always protect better.
You are missing out on alot of performance and tunability... without any less engine life.
Im guessing you have your Idle cranked, LSN rich as and HSN lean as.
I have several 3.3 engines that ive had for many many years. They all run great and keep on trucking.(for relevence sake)
#13
#14
Tech Adept

Not missing a thing. You have been misinformed and brain washed about the race fuel. I have used the same oil lube for well over 30 yrs. in all my nitro. I don't have high idle or lean out my engines All run within the factory settings. In fact they run cooler. Well below recommended temps. Low oil lube runs hotter and less tuning window. You have to run richer to cool the engine as you less oil lube to help cool the engine. More oil lube prevents a lean run and improves pinch. You need more than methanol to cool the engine down! Oil lube reduces friction and removes heat too!
#15

Heli and plane fuel in car engines is just fantastic....
That was sarcasm.
That was sarcasm.