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New Savage Octane Owner - Issues

Discussion in 'HPI Savage Octane' started by ChairmanOfTheBored, Nov 12, 2017.

  1. ChairmanOfTheBored

    ChairmanOfTheBored Member

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    Dear Savage Forum,

    This is my first thread, so please be nice :). I have had some Nitro experience when I was a kid; now 20 years later with kids on my own, I bought a slightly used Octane (muffler still in shiny black - about two tanks in, according to the previous owner).

    After running it for about 6 more tanks on my own, I still face an annoying issue:

    I run the truck for about 5 minutes and it goes great - wheelies, spins, etc. Then it slows down and does not react to any throttle movements. It clearly sounds it is about to die momentarily and guess what - it does. Getting it going again directly after is impossible, it just won't start - regardless how many pulls or choke position. I have to wait about 5 more minutes to get it going again; only to see it stalling again after a couple of minutes.
    It appears to be a heat issue but the heatsink is not really hot: I can still touch it with my bare hands.

    Of course, I read many threads on this and other forums and here is what I've tried so far:
    • Replaced CDI system
    • Replaced Spark Plug
    • Fresh fuel
    • Cleaned Air Filter
    • Reset Carb to factory settings
    Has anyone had similar issues with their truck (starts fairly easy, runs 3-5 minutes then dies, won't start again when warm).

    Thanks guys, I deeply appreciate your thoughts on this :).

    Cheers!
     
  2. thesmilingpirate

    thesmilingpirate Well-Known Member

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  3. ChairmanOfTheBored

    ChairmanOfTheBored Member

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    Thanks much for your reply!
    As a matter of fact, I've read this thread more than once before.
    As far as I understand it, I have similar issues; however, the difference is mainly that mine is not starting again for a couple of minutes once it stalls.
    Also, I have already tried everything stipulated in this thread: New CDI, new batteries, tweaking both LS and HS needles, ...

    I'm close to dissecting the engine and look for wear and tear - despite its low "mileage".

    Appreciate any suggestions :).
     
  4. thesmilingpirate

    thesmilingpirate Well-Known Member

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    Hey @ChairmanOfTheBored, I found some more information that may be helpful to you to get your Octane going. If you’ve got 11 tanks through it, you may need to break in the engine more. It's still breaking in even after 20+ tanks. You also mentioned adjusting the needle settings but they recommend that you should “never” touch the low end needle. Hard to believe, but maybe at least until you get the truck to run continuously.

    Also, check the gap on your spark plug. It should be between 0.3mm and 0.4mm.

    How’s your battery? Could your ignition system be draining it?

    Lastly, here’s a video I came across for additional information.


    I don’t have an Octane to help you further, but good luck with these tips. Hopefully you get it running properly soon.
    TSP
     
    Last edited: Nov 14, 2017
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  5. ChairmanOfTheBored

    ChairmanOfTheBored Member

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    Thanks, pal :). I guess this truck is finally teaching me some patience..

    With regard to the needles, all I did was set them back to factory defaults in the beginning. With increasing frustration, I tried leaning or riching both of them - without much success. All back to factory setting now.

    I'll check the engine tonight and let you guys know if I found anything. I'm committed to solve this one for good.
    And maybe you are right: It just needs some more tanks to break in. Stopping and not going again is just a little odd, that's all.
    Stay tuned for my report from taking the engine apart :).
     
  6. ChairmanOfTheBored

    ChairmanOfTheBored Member

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    Alright, I took apart the engine and there was no visible wear or anything along those lines - coming from a layman's view.
    The hall sensor at the crank shaft looked really dirty and gooey - my surprise in general was that the bottom of the engine as well as muffler and engine exhaust outlet were covered in a deep black oily goo. Would that be a sign for a too rich setting on the low and high speed needle?

    I cleaned everything and put it back together and went for a spin today. To my deep frustration, this mofo runs worse than before - it is hard to start and stalls after a couple of seconds. I guess the good news is that the issue as mentioned before went away... hahahaha :mad:

    Maybe it was the batteries this time - haven't charged them for a couple of days. I also suspect the new (!) CDI not working correctly as the spark seemed awfully dim.

    Maybe I should just get a new engine...
     
  7. thesmilingpirate

    thesmilingpirate Well-Known Member

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    I'm assuming you read through this guide.
    https://www.hpiracing.com/assets/documents/updates/octane_running_tips.pdf
    If not, take a look at the Ignition System Testing section and run through the steps.

    It could also be the plug. I know you said you replaced it but you can go through several plugs during "break in".
    A fouled plug is common during "break in" of an engine.

    I would get a new spark plug, even if the one you have only ran a tank or so. Also, make sure the plug you have is clean. Take a wire brush and clean it good.

    Not sure what type of battery you are using but maybe use a higher voltage battery for the CDI.
    If you're using 7.2V NiMH, maybe use a 7.4V LiPo.

    Sorry if some of this is remedial but hope it helps.
     
    Last edited: Nov 16, 2017
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  8. ChairmanOfTheBored

    ChairmanOfTheBored Member

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    Thanks much for the tips. I know this guide from HPI and have checked my CDI in the past, following these steps.
    I will do it again and just ordered three new spark plugs online.

    I use two new 6V hump packs with 1,700mAh each. Is it recommendable to switch to LiPo batteries with higher voltage?
     
  9. thesmilingpirate

    thesmilingpirate Well-Known Member

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  10. ChairmanOfTheBored

    ChairmanOfTheBored Member

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    Great! Once I have this truck running, I will convert it to LiPo. Organizing two batteries plus CDI in that battery box is a pain in the rear!
    Do you recommend using the voltage regulator to get down to 6V (as per manufacturer's specs) or keep it at 7.4V?

    I'm charging my batteries now and I hope to give it another try soon. I'll keep you guys posted.
     
  11. thesmilingpirate

    thesmilingpirate Well-Known Member

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    From what I’ve read, those who’ve done the battery mod used the voltage regulator. Just do a search for HPI Octane battery mod for clarification.

    Good luck with the next run.
     
  12. ChairmanOfTheBored

    ChairmanOfTheBored Member

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    Huh... I did test my CDI again and I noticed something not quite right. Last time I performed the steps as per HPI's running tips it was still light outside and I came to the conclusion that all is fine with my CDI.
    Now it is already dark here in Germany and I did this in with dim lights in my "man cave" and I definintely saw sparks in the silicone isolation of the spark plug when pulling the cord without having a spar plug in it. This is the relevant part from the manual:

    Step 2 – Testing Spark Plug Cap Insulation 1. Remove the spark plug from the spark plug cap. 2. Slowly pull the starter cord and observe the interior of the spark plug cap carefully. If you see a spark arcing through the silicone boot to the metal shell of the cap, the Ignition System needs to be replaced.


    I guess I need some help interpreting this. I did saw really small sparks in a dark environment in about every second pull. But here is the thing: HPI states the following:

    If there is no visible spark but you hear a snap/crack, proceed to Step 3


    Doesn't this mean that there has to be a spark somewhere in the cap and I just see it since it is so dark here? Can maybe someone with a well functioning Savage Octane check whether they see sparks in a dark environment?

    Thanks again, your content and moral support means much to me :)
     
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  13. thesmilingpirate

    thesmilingpirate Well-Known Member

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  14. ChairmanOfTheBored

    ChairmanOfTheBored Member

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  15. ChairmanOfTheBored

    ChairmanOfTheBored Member

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    Alright, the new CDI has arrived. Since it is a bit bigger than the original CDI, I cannot confirm that it fits just yet. I tried hard to rearrange the two battery packs but no luck.
    I hope nothingbetr2do checks this old thread and shares his approach to make this fit.
    If I cannot make it fit, I’ll just strap it at the back of the truck to test if the engine runs better. I hope to have some time during the weekend.
     
  16. ChairmanOfTheBored

    ChairmanOfTheBored Member

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    Alright, another afternoon run - another frustration.
    I have mounted the new CDI with a zip tie on the back of the truck (since I had a hard time fitting it in the box) and connected the wires to the battery box.
    All batteries were fully charged, I used a brand new spark plug. No luck.

    It showed the same odd behavior: It starts okay (after a couple of pulls with Choke closed, I open the Choke valve and it starts). It goes for a couple of minutes and dies without being able to fire up afterwards.
    It appears to be running too rich: a lot of smoke is coming from the exhaust and an oily goo is dripping from the pipe.
    Of course, I've tried to carefully lean it out but could not observe any difference.

    In order to fix this running issues, I've sank already a couple of hundred Euros in this truck after purchasing - this is really irritating...

    Don't get me wrong - I really love this truck. It looks really mean and the few times it was running well, it put a big smile on my face.
    As a matter of fact, I've already upgraded a lot of parts: Double Integy shocks with piggyback on each wheel, new LRP/Mielke exhaust (the stocker is way too loud for my taste), Integy aluminum C hubs, 24mm hubs from HPI Baja, new rims and tires (Proline Bow Tie 40s on Wabash rims) and some other smaller things.
    Now I just need to fix these running issues...

    Unfortunately, with young kids and a job that involves some travel, I really lack time to consistently follow-up on this. I'm really close to just replacing the engine to solve this once and for all.

    Since I can rule out batteries, CDI, exhaust and drive train... I'm not left with many options to troubleshoot. I'm thinking the hall sensor could cause the odd running behavior; I'm going to replace it as a last (almost hopeless) attempt to fix this engine...

    I appreciate any hints or tricks (did I miss any potential culprit here?) or just some moral support :).
    Thanks much, guys!
     
  17. thesmilingpirate

    thesmilingpirate Well-Known Member

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  18. ChairmanOfTheBored

    ChairmanOfTheBored Member

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    Hey man, I haven't had the time to check. Maybe I manage to replace the hall sensor and cable tonight - I will definitely post the progress once I manage to continue my work on it.
    I'm committed to solve this for once, no matter what :)
     
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  19. ChairmanOfTheBored

    ChairmanOfTheBored Member

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    Hey guys, I think I have made SIGNIFICANT progress. As I mentioned before, I swapped out the hall sensor with a generic one that came with the HobbyKing CDI that I purchased (in vain). I had to extent the screw holes with a file to make it fit to the Octane engine block. Once installed, I connected it to the original CDI from HPI (that one I had replaced already).
    I only filled the tank half full and loaded the truck in the trunk of my car, headed for the next stripmall parking space.

    It started after a handful pulls with choke open and ran amazing once it heated up a bit. I had like half an inch of snow here and this beast really drifted and turned - it had way too much power for the grip it got on the thin layer of snow.
    The half tank gave me about 10 minutes run time - or a big fat grin on my face for that matter.

    Once it died, I thought the tank was completely run dry but there was still some gas in it - roughly at the level of fuel filter - I reckon this is pretty normal, isn't it.

    I hope to find some more time this week to verify these results. Today, my patience and perseverance have been rewarded greatly! Exchanging the CDI's hall sensor really did the trick, apparently.

    I'm super happy today - I just hope this progress is sustainable :)
     
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