Home Forums TaG Rotax Max Rotax EVO parts failing?

This topic contains 53 replies, has 21 voices, and was last updated by  Eric Alexander 2 years, 11 months ago.

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  • #47032

    Michael Cohen
    Participant

    Well a frustrating weekend of racing…..
    So just asking…have any other people that have upgraded to RVO had parts failing?

    After getting the upgrade we had difficulty’s getting RPM’s from my son’s Junior motor. The following week two days ago Saturday we practiced and occasionally seemed like the motor was missing.

    Then race Sunday my son told me that the motor was shutting off during qualifying. We checked what we could and it seemed ok. Then in the pre-main after the warm up lap the kart died and he was pushed off the track and he missed the race.

    I checked everything again, and I swapped everything I could. The bummer is it seemed to be intermittent. When it happened we had no spark. Of course when switching everything we could not replicate the problem…… Finally after trying everything over and over hoping to at least be able to race the main, I swapped out the Electronic Box (some might call it an ECU) and when I put mine back in it died after about we restarted it. So finally we found the bad part….(I hope..).

    That box is a sealed box, I would not think it would be intermittent, rather it work work or not. That made me think it was in the harness. But the new box did fix the problem. I checked the wiring and the plug a number of times….. Has anyone else had a problem with the box? I found two other people at the track that had problems with the Electronic box. I did call MAX SPEED and they said they have not heard of those failing and I was the first they heard of that…….

    Also two people at the track burnt up the new wiring harnesses, one apparently burn itself while the other one was user error, as the metal on the top of the cover shorted it out.

  • #47094

    Mark Traylor
    Participant

    I have heard from one dealer that I wont name that he has had a bad harness and a couple of the 25 pin connectors tot he ecu go bad.   So I don’ believe they have heard of no issues.  This dealer has been working on getting parts replaced for a while now.

  • #47096

    Brett Clatt
    Participant

    Michael,
    What kind of RPM’s were you trying to get out of the Junior motor?
    You’ll definately want to stress relief the connectors. I’ve heard a complaint about the electric power valve on the EVO senior/DD2 motor, but nothing negitive about the junior upgrade.

  • #47116

    Scottie Melancon
    Participant

    Are you grounding to the correct location? The EVO requires the ground to be installed on the left rear cylinder head bolt. We had a few folks at our track that had similar issues. They attached the ground to the proper location identified in the installation manual and it fixed the issue.

  • #47136

    Michael Cohen
    Participant

    Mark:

    As I was ordering parts yesterday the supplier told me he has seen a number of them fail…So I agree with you.  Its just strange to me that as a sealed unit it was intermittent..?

     

    Brett;

    At one point we were having a hard time getting over 12,500 RPM, then without much change it seemed to get better. I hate to assume anything with ROTAX, but after having the problem with it cutting out etc I assume it was the ECU as that seemed to make run way better.

     

    Scottie: Yes I do have it grounded to the head bolt, as well as another ground strap to the cases. I have heard this from others to use the head bolt so I am, I’m not sure why that would make a difference… Aren’t you grounding metal to metal why would the head bolt be different than a bolt on the cases?

    Thanks everyone for the input…..

     

    Michael

     

     

  • #47239

    Eric Jacky
    Participant

    Well, you just described our weekend to a tee.  Our Evo failed seven times over a double header weekend.  Practice, qualy, Premain, main events, completely random, never permanent, my little guy  fought to keep it alive.  We bought a new battery, we swapped the layout of the battery box so the kill switch is now in the back.  I didn’t give a thought to it being the harness/ecu until I just saw your post.  Def sounds like there may be a bigger issue.  We have our ground on the correct cylinder head bolt, so we don’t think that it is.

  • #47242

    Michael Cohen
    Participant

    @ Eric; Did you solve the problem? Did you swap the ECU?

    • #47252

      Eric Jacky
      Participant

      We don’t know for sure.  He stayed alive during the final on Sunday after we spent all weekend chasing it, but when I watched the video last night, I’m pretty sure it was cutting out.  After I saw your post about your issues, I sent an email to a Rotax rep who helped us with other issues and let him know.  We only have a week to next race at Ocala, so hopefully can get it sorted by then.  Hoping they can send a new one that we can try.  When it runs it runs brilliant.  Unfortunately, it is not 100%.

  • #47284

    Luis Soto
    Participant

    We are seeing a similar issue on my son’s Junior Rotax: There’s a huge delay, or lag between throttle application and engine response. If you basically “stand on it,” there’s almost a full second delay before the engine responds. Coming out of the corners, my son says he has to “roll” onto the throttle much more than before the upgrade, and then there’s “a lot of popping” 3/4 down the main straight at his home track – like he’s topping out. This is not how I understand the Evo is supposed to work (?). We have tried with the supplied 130 jet, 128, 122, 125 and 118, which is what’s in the carb now. His coach/mechanic is sure he grounded the wire in question as per the instructions. I thought the problem might be a faulty ignition coil, but some people I’ve talked to say it’s carburation. Any thoughts?
    Thanks in advance…

  • #47344

    Eric Jacky
    Participant

    Luis, they definitely like to be rolled on vs stomped on.  We’ve noticed that as well.  I’m no jetting expert by any means, but I’ve traditionally heard “popping” is associated with being too lean.  We’ve been running best at 115 in high humidity for our micromax, but the junior may want a little more. 118 may simply be too lean for your conditions.  I’ve reached out to Rotax about the coil question and so far have not heard anything back.  After spending a nightmare month chasing this EVO, I’m two seconds from getting an LO206 and being done with this Rotax stuff.  Lots of frustrated folks down here in FL.  We’ve at least had ours for a month, most people are just getting their kits this week.  Plus they are saying the kit is now including a throttle slide stop which it didn’t before, which tells me they realize there are problems and are trying to do something about it.

    • #47346

      Luis Soto
      Participant

      Thanks for the response!
      We’ll be back in a week to test again – my son has plenty of experience with the “prevo” Rotax throttle, but to be honest, the amount of rolling the throttle he is doing is ridiculous: way, way more than before the kit. After what you wrote, I’m of a mind to start again with 130-125 jet and go from there. Our coach/mechanic also changed the needle position in the carb, to chase the lag. I’ve also been trying to get a hold of another carburetor, to be able to rule that out.

      Maxspeed did suggest to check the battery amps and voltage – to try that first before the carb. I’m obviously not an engine tuner, but the three reputable ones that I’ve talked to seem convinced it’s a carburation issue. I’m challenged that we don’t have access to the kart until the testing day, so pretty much we only have that one day to sort it out before the next race…:S

  • #47347

    Eric Jacky
    Participant

    just got this from my Rotax contact. They are aware of the issue, and they believe it is not electronic, but rather not enough RPMs on the low end, and the engine is just choking off.

    “We have come up with a solution to this problem, but many times the problem was one of the engine not rising up in RPM’s. We had a special sleeve made for the carburetor. It is CNC’d, and is 33mm long to put inside the cap of the carburetor.”

    They shipped a bunch to Maxspeed, but I’m guessing its not going to be cut and dried getting one.  I’ve reached out to our dealer (who learned about it from we, the customers) as MS has apparently not sent out info.  She is going to try and get me one, but not making promises.

    this jives with what I’m seeing the last couple days with others in our class getting their kits with a mysterious new piece for the carb that wasn’t there in our kit.  So hoping that helps, now its a matter of getting one!

  • #47349

    Vincent Ciolino
    Participant

    Aww now we know the reason for the mysterious piece.  A bulletin will be coming out shortly to address this.

  • #47624

    Michael Cohen
    Participant

    Well after thinking we solved the problem, thinking the ECU failed…..it appears the its the connection. I had it zip tied so it would not vibrate etc…. but strange enough it started cutting out again after a full day of running great. I pushed a little on the wires that go into the connection and the motor rev’ed up? I’m not sure if I get another wiring harness or try to take apart the one I have and see if I can make the connections better. After removing the zip ties and unplugging it, I found what looked like arching around the connector holes……

  • #47689

    Mark Traylor
    Participant

    Michael,

    Which connector?  I have heard of bad harnesses.   cant miss the giant “made in China” tag.

  • #47702

    Michael Cohen
    Participant

    The plug / connector that the ECU plugs into. Even with zip ties holding it together there still was what looked like arching around the female connector holes…..

  • #47712

    Adrian Baran
    Participant

    Considering the quality of the harness I won’t be surprised if some of the problems are originating there. It just screams quality…

  • #47713

    Jerry Brown
    Participant

     

    e.

  • #47781

    Mark Traylor
    Participant

    maybe a little appilcation of dielectric grease on the connector would help?

  • #48204

    Luis Soto
    Participant

    Nothing apparently related to electronics, but we had a nasty throttle response issue with our Junior upgraded engine (as per my previous post). Maxspeed was kind enough to send me a new carb and sure enough, as soon as we swapped carbs, the issue was gone immediately. No other changes made, and Maxspeed is taking the defective piece as a warranty return. So something else to consider.

    What’s more, the famous ground wire is not even connected to where it’s supposed to (top of cylinder head). Driver coach/mechanic doesn’t seem convinced this ever had an effect on anything (because there doesn’t seem to be any popping, etc. now)…

    Luis

  • #48335

    Chris Pacitto
    Participant

    We just had our day ruined by this same issue.  Intermittent loss of spark.  Each time I thought I had it corrected it simply recurred again the next session.  Has anyone definitively figured out what is causing it yet?

    We have a micro Prevo motor with the Evo kit installed.

  • #48366

    Christian Sarnecki
    Participant

    I’ve been having a problem with my Evo kit also, I own a junior kart that just received the upgrade. To my surprise when I went out for practice the kart would not exceed 10,000 RPM’s. I’ve changed about 8 jets all without results and the motor pops until it hits 10,000, then the motor bogs down rendering my straight line speed close to none. The fuel pump, clutch and more internals have been changed with no change at all. I am now contemplating on whether I should send my kit back of put the older carb on.

  • #48713

    Michael Cohen
    Participant

    Hey Chris P;

    Sounds like we have the same issue….. Did you solve the problem? At this point I’m thinking it must be the wiring harness, likely something in the plug / connector to the ECU.  I’m going to try to find another one to swap out for this weekend…… Hoping that solves the issue.

  • #48817

    Christian Sarnecki
    Participant

    From all I have researched I think I might have found a solution. I bought my EVO kit for my older motor a long time before my racing season started so I could get an advantage on time. After a side by side with another kart who bought their kit later than mine (2 weeks  before the season to be exact) I found out that their kit had some components (possibly wiring) that my kit was lacking. Later in the day another driver who purchased the kit around the same time I did experienced extreme RPM loss and ended up having the same problem. I then came to the conclusion that the “older” EVO kits are failing and need to be replaced. I am currently in the process of getting a new kit and will post again if the problems do not show themselves again.

  • #48823

    Chris Pacitto
    Participant

    No, I did not solve the problem.  I did find that there was slight tension on the harness going into the ECU.  I rerouted the wires to relieve any tension.  It has been starting fine every time I try, but we have not been back to the track to test yet.  It was an intermittent issue, so I’m not at all convinced we have it fixed.   Should be able to test it out next Saturday….

  • #48863

    Michael Cohen
    Participant

    Ok so this weekend we did NOT have loss of spark….. I’m convinced its in the wiring harness plug…..

    I loaded the plug with Dieletric grease, zip tied the plug and as Christian stated above I found out that the newer upgrade kit also included two rubber mounts for the coil and ECU…my kit only had one so I added one..now both my coil and ECU are rubber mounted.

    My concern is that the connection will fail again. As I’m hearing about this from more than one person, I’m hoping that Rotax upgrades the harness to have a better connector….

  • #49135

    mark sawatsky
    Participant

    Today I was in 2nd place in the pre-final within sight of the checkered flag and my engine died and I finished third-the ground wire on the EVO harness broke off at the head. Then in the Final race, I was in 2nd place again and the ground wire of the driver in front of me broke and he was out of the race and I won. I lost one position today and gained one position because of broken ground wire on the EVO. Let this be a warning.

  • #49621

    Ed Portz
    Participant

     

    just some of the fun things I’ve seen over the past couple months–

     

    1. bad connections

    2. motors not running out of timing. (you have to put 2 gaskets behind LOWER TIMING magnet to make your upgrade work… but only on some motors! I own one.   WOW THATS LEGAL! of course officials allow it.)

    3. no upgrade kits available.

    4. connectors breaking.

    5. OLD PIPES? NEW PIPES? NEW PIPES W/ OLD BAFFLES? new pipes w/ new baffles = a $$$$$ dyno time

    6. wire harness caught on fire also

    7. officials doing away w/ a bunch of rotax max rules to handle all the issues w/ these POS EVO kits.

    8. rotax series w/ world tickets running non evo and evo together w/ both being scored separate. So you could be 5th but the first non evo and be 1st in points after round 1.

     

    • #49786

      Ed Portz
      Participant

      Imagine that 3 days after my last post they “officially” changed all the rules to cover all the problems i stated. lololololol

  • #49795

    Ray Chiappe
    Participant

    Ed Portz, that’s the funniest thing I have ever seen as applies to Karting!! Especially since I run a Rotax. I’m still laughing!!! LOL doesn’t quite cut it right now!!

  • #50047

    Andy Rylance
    Participant

    We also had electrical issues with our Evo this weekend. We thought initially it was the ECU, but swapping did not help, no spark. We then swapped the coil and the engine fired ok. However the kart never even made the first turn before the engine failed again. After playing with the connectors while cranking the engine, we discovered it was a poor contact of the low voltage connector to the coil. Push it in, the engine fired, release it, and it died.

    In my opinion, the harness looks to be of good quality, but it is too stiff, this is placing undue strain on the wires inside the connectors. Also some of the materials used in the connectors appear to be low quality (dull silver color) rather than gold plated which is standard in higher quality connectors.

    I hope that Rotax admit these issues and address urgently. Spending hundreds if not thousands of dollars on a race meet only to have a harness failure and not even race is going to go down well amongst racers.

  • #50050

    Michael Cohen
    Participant

    Last weekend at our track, we had a number of karts fail due to electrical problems. It really is a bummer to take all the time and efforts not to be able to race….. I would hope Rotax is at least listening and hopefully testing and retesting the wiring and connectors.

  • #50059

    Matt Clark
    Participant

    Just got called to order my kit today…fingers and toes crossed the delay was due to them sorting out these issues :(

  • #51564

    Roman Alekseenkov
    Participant

    Had an issue last weekend.

    5 minutes before the heat race, all of a sudden kart wouldn’t start on a stand. Quickly changed e-box and coil, it fired, got it out on a track.

    Two laps into the heat race, engine stopped revving past 9,000-10,000 RPM. Couldn’t start it after the heat.

    Tried electrical degrease on wiring harness connectors and it didn’t help. Installed a new wiring harness and it’s all good.

  • #51568

    Michael Cohen
    Participant

    Bummer about failing in the heat race, but at least you had the spare parts to get going again. I really feel as if it must be in the harness’s plug…. I hope Rotax is aware of the problem….

  • #51570

    Roman Alekseenkov
    Participant

    Will be sending a warranty claim to Rotax…

  • #51572

    Matt Clark
    Participant

    I’ll consider myself lucky, two races so far and not a problem with my kit…

  • #51997

    Roman Alekseenkov
    Participant
  • #52963

    Roman Alekseenkov
    Participant

    Another harness failed for me just last Saturday. All of a sudden, power valve stopped working and it would stay open all the time. We were chasing it down for several hours, finally replaced harness after replacing everything else and it started working.

    I guess I’m that unlucky that I hit EVO crank sensor issue on two different engines and two EVO harnesses failed for me. Even engine starter failed last week also.

     

  • #53006

    Roman Alekseenkov
    Participant

    Yep. The problem looks exactly the same. Awesome description on the forum!

  • #53034

    Nigel Baines
    Participant

    Thanks!

    Well, it turns out we had another member with the failure of the PV staying open at the club tonight. This time we were able to locate this problem to the Orange/Green wire from the Ignition connector to the PV Solenoid connector, however, the issue was with the connection on the Ignition connector this time! New harness required however.

    It has also come to light at the club that anyone who still has their PV solenoid hard mounted to the new EVO bracket can experience issues with the high RPM. Some karts would top out at 13800-14400 before the end of the straight, but once the rubber stand-off was installed, this problem was also resolved and the karts would rev freely to 14900. I believe the rubber stand-offs came in the later release of the EVO PV kit too. We think this may only become an issue once the engine is producing these high RPM’s due to the vibrations/resonance on the solenoid.

    Nige.

  • #53112

    Ambrose Buldo
    Participant

    Thanks for the link. I will read it tonight. We’ve been experinging a problem with our Upgraded Rotax Evo Max were the engine would just rev limit at 12,400 RPM. The more we ran the kart the more often it would occur. If I ran 8 sessions of 10 laps each. First few sessions engine reved to 13,900-14.300 no problems. Later in the day every few laps it would rev limit at 12,400 RPM. For example, mid-day sessions, about half the laps would be rev limited. it would be fine, then not, then fine again. No pattern. By the end of the day, most of the laps would be rev limited. The isse clearly shows itself in the AIM data. Going down the straight the revs flatten out like a table top when the issues occurs. it has been a challange for the shop (Who installed the kit) as the problem is inconsistant. If they take the kart out to test it for a couple laps it may be fine, however if I run mutliple sessions over the course of the day, I have the issue.

    Are these parts covered under warrantee? For how long?

  • #53148

    Michael Cohen
    Participant

    @ Ambrose – Have your read the tech bulletin re the gasket on the coil pick up? Might that be your problem? I understand some people were having issues with limiting RPM’s due to this?

    Also we have have a few people at out track have the “Ring” wire connector crack and break that attaches to the ground on the head, as well as breaking on the one next to the battery…….

    Its also funny how many of the RED covers are missing on the starter switch’s as the seem to fly off.

     

  • #53405

    Nigel Baines
    Participant

    @Ambrose – 12,400rpm is basically all the engine will rev to if the Power Valve is closed.  Are you running your Power Valve on the original Vacuum set-up, or have you upgraded to the Pressure set-up?

    You could put your PREVO Power Valve/RAVE back on to narrow down your problem too.

    Cheers,

    Nige

  • #53442

    Eric Alexander
    Participant

    @Ambrose – also be sure you have the isolated spacer between the black EVO mounting bracket and the E-RAVE solenoid.  Without the isolator, the motor vibrations will override the solenoid and close the power valve around 12,000 rpm.

  • #53494

    Ambrose Buldo
    Participant

    Thanks for the feedback guys. Not been able to get to the track for a few weeks.

    To Michael’s point: I did not have the gasket installed. I installed one. It did nto solve the problem. I then installed 2 gaskets and engine would not start so I went back to one gasket. I will check the ring connectors, but I dout it is the issue.

    To Nigel: I did not istall the upgrade, the Rotax shop did, I did not get the installation guide. Kart has the new style Electronic power valve assambly so I assume this means it is the upgraded to the Pressure set-up? Is this correct?

    To Eric: I am pretty sure all parts are hung off the bracket with rubber isolators. If it is the coil or the Selenoid, or both, I don’t know by memory. I have to see the Engine and take a picture.

    In a link in previous post I saw someone shooting video of power valve opening and closing. Maybe I should do the same. At least I can confirm to the shop that cause is the power valve not operating properly.

    • #53499

      Blake Newson
      Participant

      Hi Ambrose, those are my YT videos of the power valve. If you really want to see if your power valve is not functioning properly at the high RPM range, there is a very simple test. Disconnect your air line that goes into the power valve. Take apart your power valve and place the spring on the INSIDE of the bellows and put it back together. (leave the air line disconnected) This will force the PV to stay open all the time. Take it out for a spin and see if the engine works any better at high RPM’s. It will be sluggish out of slow corners, but that is fine for the test.

      If you now have the expected high RPM performance, then you know you have a PV control issue. If it makes no difference at high RPM’s then you need to look elsewhere.

      Perhaps an even easier option is to leave the PV as is. remove the air line that feeds it from the solenoid. Blow into the line and you will see the PV open. Without letting any air out, block off the air line, so the bellows stay full of air and therefore stay open for a couple of laps while you do your test. A couple of small zip ties, will pinch off the air line nicely.

      You could also try installing your old PV if you have one, but that is more work than either of the suggestions above.

      Good luck.

      Blake

  • #53603

    Roman Alekseenkov
    Participant

    Is the consensus here that pretty much everything should be rubber mounted, i.e. Coil, Ebox, and PV solenoid? 1 rubber standoff for coil, 1 for ebox, 2 for PV solenoid?

    • #53629

      Blake Newson
      Participant

      Yes. Rotax provides isolators for all three. I use two on the solenoid but most are just using one. It seems like either will work.

  • #53630

    Roman Alekseenkov
    Participant

    Ok. Thanks, Blake

  • #53631

    Eric Alexander
    Participant

    Yes.  Every electronic box should attach to the bracket with a rubber isolator.  The E-RAVE solenoid only uses one rubber isolator as opposed to two.  All wire looms should be folded back and secured to their respective box with a zip-tie to remove strain from the connector.

  • #53973

    Ambrose Buldo
    Participant

    I took a look at the engine over the weekend. Based on the feedback here, I notices two things:

    1. The PV seloniod was hard mounted with two bolts to the bracket. Not having access to purchase an isolator until I get to the track, I mounted it loosly to the bracket making using a two stacked fawcet washers to create a home made isolator. I used two bolts.

    2. I also noticed that the when hitting a big bump the coil would hit the side of the seat. You can actually see by looking at the coil and the seat where there would be contact. Hanging off the isolators these parts move around allot. The video posted in this thread illistrate that effectively.

    Hopefully, these two fixes should address the RPM limiting issue. I won’t be able to hit the track for a couple weeks to test it out.

    I think the issue is vibration caused. I looked at the data and notices an intresting trend. When hustling to get a fast lap, it would rev limit at 12,400 down the straight. If I would take it easy during the lap (Let’s say stuck behind slower traffic or I was catching a breather) it would pull all the way to 14,300. At OVRP you need to use the curbs quite a bit, so I think the extra movement and banging during a fast lap overwhelmed the components.

    If these adjustments adress the issue great. However I an disappointed at the the experiance and the design. I can’t see the plastic tabs holding these commpnents lasting very long. The coil and hte e-box are fairly heavy. This movement not only stresses the mounting points but also the wires and hoses. In a year, I am sure you’ll hear about these tabs breaking and replacements being needed.

  • #53990

    Eric Alexander
    Participant

    BINGO!  Isolate that E-RAVE and you should be good to go.

    I agree the design is lacking.  I think I will purchase a 2nd isolation mount so I can use two on the E-RAVE like Blake is doing.  Its clear the solenoid was designed to hard mount with two screws and using a single iso just seems asking for a tab failure down the road.  And that’s been the problem the whole time with this EVO update.  Its poor engineering making up for prior poor engineering.  I admit the engine runs like a scalded dog now.  I’m thoroughly impressed with its performance.  But you’d think they’d have designed this stuff right the first time to deal with the vibrations.  And having the need to iso the solenoid should ultimately cause a redesign of the solenoid housing to better fit the new mounting method.

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