HPI Savage Octane starts then stalls

Anders Jonsson

New Member
Messages
4
Never run this type of carburetors dry, the membrane can dry out and stop pumping gas!
 

Jam Racing 1

Well-Known Member
HPISF Supporter
Messages
4,716
Never run this type of carburetors dry, the membrane can dry out and stop pumping gas!

Not true, there will be plenty of leftover lube to keep it from drying out...... besides when ya run it next time you will not have trouble tuning and running the rig......
 

jeepjunk94

Active Member
Messages
88
I adjust my LSN with the engine running along with the idle. I also found that plugs will fire outside the cylinder but not under compression. I also run low octane fuel 87. That is what HPI uses when they test run. The carb screws are very course thread when they should be very fine so the slightest turn makes a big difference creating a difficult to tune situation. These trucks are a major pain to tune, I have been trying for a long time to get mine right, I am close but not there so take my suggestions as just that cause I still don't have this truck figured out. I still can't get a slow idle out of mine, it's close but still engages the clutch making it want to creep forward.
 

sharkattack99

Well-Known Member
Messages
925
Location
Moses Lake Wa
I've noticed alot of post about the starting issues on the octane, as well as the braking of the pipe maybe I will wait on buying the octane till theses issues are resolved. To bad too really wanted one mainly cause of the cheaper fuel.
 

jeepjunk94

Active Member
Messages
88
I've noticed alot of post about the starting issues on the octane, as well as the braking of the pipe maybe I will wait on buying the octane till theses issues are resolved. To bad too really wanted one mainly cause of the cheaper fuel.
HPI has fixed the pipe issue with there tuned quiet exhaust you can buy, lol! For the rest of the issues I predict they will do nothing.
 

trev616

Member
Messages
37
I'm sending the truck back to HPI. I put a new engine in it (as i screwed the other one up trying to rebuild it) and it still does the same thing. Pretty sure the ignition system is faulty.
 

trev616

Member
Messages
37
Got the truck back today. I had a list of things they did to it. One of which was that the servo horn was not centered properly, I do not remember ever touching the servo horn so how this could have gotten off center is beyond me. I also got a statement saying that the were able to get the truck running and performing like it should. I find this very peculiar because I pulled it out of the box and it was doing the exact same thing as before. Starting and stalling. I made carb adjustments and still nothing. I have no idea what to make of all this.
 

Jam Racing 1

Well-Known Member
HPISF Supporter
Messages
4,716
Sorry to hear you are still having issues with the truck....I know is a pain to deal with a manufacturer at times,
I recently bought a new Ofna.32 engine for one of my trucks to replace the SH .28 as the sleeve is kind of worn, and while it would run, it was not right would not idle down and racing like it had an air leak... I traced down the trouble to a faulty carburetor and when I called OFNA I was treated like I was just stupid..... the engine runs fine using the SH .28 carburetor on it, but with that composite piece of crap carb that came on the engine it just will not run at all..... as for that plastic piece of trash OFNA calls a carburetor it is sitting in the spare parts bin never to be looked at again.....
 

rcnut14

I give bad advice
Messages
1,229
Location
lancaster county, pa
no, it's not hpi. it's the truck. the octane is a very new design and still has many bugs( as u have found out first hand) but most of hpi's products are very good.
 

DMZamora

Member
Messages
26
ngk spark cm6 throws away the original spark is useless do a mix gasoline oil (1 liter of gasoline and oil 25cc) then please reset carb, by the book
Very late on this, but it's an important point.

To calculate mixture, it's mandatory to put all things down to the same units. One liter equals 1000ml, as 25ml equals 0,025 liters.

HPI recommends an oil ratio of 25:1. This has nothing to do with 1 liter gas / 25ml oil, which will result in a 40:1 ratio (1000ml divided by 25ml = 40).

To have the correct 25:1 ratio you need to mix 40ml of oil to each liter of gas (1000ml divided by 40ml = 25).

I know this is pretty basic, but there's a whole lot of people that thinks that a 25:1 ratio means what Roberto said.

Not saying that it's the case here, but an oil ratio way lower than required can cause the stalling issues you're having.
 
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shaun will

New Member
Messages
3
plz plz could someone help me with carb settings tryed factory settings nothing any ideas cheers
 

F-Type

Well-Known Member
Messages
266
Location
Gothenburg - Center of the Universe
I am in break in with mine, and today had these issues with start and stall. I also noticed, when I got the car running for a short while, servo twitches, I have not seen that before.

One thing that I did notice during this evenings escapade with the Octane, was that there was a glitch in the contacts between the ignition box and the sensor (?).
And my guess is that these issues with the car starting and stalling, is not carb tuning issues. It's electrical issues. The start and stops are way too distinct for it to be anything but electrical, that's my wild guess. I will replace those cheap junk contacts with something more reliable, that's for sure. Then I noticed the ignition box works with 8.4 volt supply, so I will try with a 2S LiPo as well to make sure voltage supply is not an issue.

Considering how many 2-stroke engines there are around these days, simple cheap ones in gardering tools etc, that all work fine without any break in or tuning what so ever, it is a mystery how HPI managed to **** up so badly with this one. And obviously they still haven't even figured out what the real issue is themselves.

Also the carb, as I understand, is a well know and widely used carb, so I am convinced it is not a carb tuning issue. And this is more or less what HPI says too, keep it at factory setting during break in.
 

shaun will

New Member
Messages
3
thanks for reply think i am going to sell it on ebay and bye another baja had no problem with them or try that mavrick truck
 

F-Type

Well-Known Member
Messages
266
Location
Gothenburg - Center of the Universe
Did some more trying but without much success, the motor runs a few seconds max before stopping. It's not that hard to start, but it always stops again within 0-3 seconds.

I did the CDI check recommended in HPI's running tips, and the CDI checks out fine.
I've got two spark plugs, the original and an NGK, the NGK has run about 2 tanks, both seems to give good sparks and it doesn't make any difference which one I use. I have two more plugs on order, just to be safe.

I noticed that I seem to get quite an amount of gas out of the exhaust pipe. See pic below. I also saw a big spot on the floor.
what could be the reason for this? Is it just that I keep pulling the starter that makes more gas pass through than what is actually combusted?

I also tried using a can Start-gas, spraying into the carb, but that did not seem to make any difference, which strengenths my suspicion it is an electric problem rather than carb tuning.

DSC_0919.JPG
 

trev616

Member
Messages
37
Well after months of trial and error and no help from Hobbyco, I bought a new ignition system and the Octane seems to want to run again. New ignition system ran for a few tanks and never stalled. I do no understand why Hobbyco would say that it ran fine for them but yet I get it back it was doing the same thing as before. Anyways if anyone was wondering, the ignition system was weak and I got a new one and it works now.. I wonder if Hobbyco will refund me the money I paid for the new one as their "techs" couldn't seem to figure this out either.
 

Alexander RUS

Member
Messages
6
Location
Moscow
Well after months of trial and error and no help from Hobbyco, I bought a new ignition system and the Octane seems to want to run again. New ignition system ran for a few tanks and never stalled. I do no understand why Hobbyco would say that it ran fine for them but yet I get it back it was doing the same thing as before. Anyways if anyone was wondering, the ignition system was weak and I got a new one and it works now.. I wonder if Hobbyco will refund me the money I paid for the new one as their "techs" couldn't seem to figure this out either.
Thanks for your story! I've spend one month with this problem, and today I've bought a new ignition system, so I hope It will be a solution for me like for you!
 

F-Type

Well-Known Member
Messages
266
Location
Gothenburg - Center of the Universe
Today i ran the motor with the car standing still, wheels in the air, increased the rpm a bit with the idle screw. The car ran fine for about one thank. Then it suddenlu just stoppen. From then on I experienced the start/stall problem, very clearly. Changed to a fresh/cleaned spark plug and then the car ran fine again, started on first pull.
 

trev616

Member
Messages
37
Knock on wood my octane seems to be running fairly well at this point. Truck is shifting smoothly. It doesn't seem to like a whole lot of adversity however, truck will stall going up a hill or driving through grass. Other than the overheating issue it wants to run so this is good news.
 

F-Type

Well-Known Member
Messages
266
Location
Gothenburg - Center of the Universe
Today when I started the Octane I hade some start/stall issues. Swapped to a new spark plug and it started wihtout any issues. The car ran so-so (as it always has, breaking in), but all of a sudden, right out of the blue, it made a wheelie, quite surprised I managed to release the gas just before it flipped over. Right after I could not get it to make a wheelie again. A while later, again right out of the blue, it made another wheelie, almost flipping over.
At the end of the tank it began running quite poorly and ended with the start/stall issues. I will clean my spark plugs and continue the break in. my car is beginning to come alive, that is for sure :)
 
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