Zuma 125 difficult starting?

Discussion in 'Battle Scooters' started by longhaul747, May 15, 2014.

  1. k-moe

    k-moe Long timer

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    Jerry, I have had the original fuel pump from my scooter in my hand, and had it apart. The problem has nothing to do with ethanol, or any other fuel. It's a clearance issue between the impeller and the pump housing. Please quit talking out of your anus. :deal

    When the first 2009's had trouble we were told the replacement pumps were of a new design, yet they had the same part number (no revision number). My replacement pump failed the next summer (same symptoms; pump failure when hot, ran fine below 90ºF ambient), which is why I replaced it with an aftermarket pump from a different supplier. I hope that Yamaha remedies the problem in a more permanant fashion then they did in 2010.
    #21
  2. longhaul747

    longhaul747 Been here awhile

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    I had the replacement pump changed out this morning. It took the shop about an hour and a half to replace but I think a lot of that was paper work. Scoot runs fine with the new pump and I don't notice any difference other then the new pump sounds a bit more course.

    Interestingly the problem I was originally having has not returned since the ECU reset. So I am kind of thinking nothing was wrong with my original fuel pump but Yamaha insisted it was and wanted to replace it. The repair ticket is still open just in case the problem returns and it was not the fuel pump.

    One thing is even though the weather has been nice the past few weeks it has not gotten extremely warm. Maybe low 70's with a hint of low 80's on a few days. The acid test will be 90F + and lots of humidity.

    Hopefully if it was in fact the fuel pump the latest design will cure the starting issue. Seems kind of odd that such a simple and benign part is giving Yamaha and is customers such grief.
    #22
  3. k-moe

    k-moe Long timer

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    The Zuma ECU is a simple beast. the only thing the reset does is make the ECU clear values for the oxygen sensor and temp sensor. The fuel maps are fixed, so there is no "re-learning" that occurs. I tried resetting mine a dozen times before replacing the fuel pump the first time.

    I do hope the new pump is better for you. If that one craps out I'd be looking at a aftermarket pump, and asking Yamaha (nicely) to pay for a portion of it (never hurts to ask).
    #23
  4. acejones

    acejones Long timer

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    Those pics of deposits in a Carb don't prove ethanol issues. I've seen carbs with deposits like that long before we had ethanol in fuel.
    #24
  5. longhaul747

    longhaul747 Been here awhile

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    So far no more issues with the fuel pump and it has been pretty hot and humid.

    However a new issue came up yesterday that is making me go hmm!

    Started it in the morning and it turned over just fine and fired right up. Road for about 10 miles checking on my folks place while they are out of town. Got back on the Zuma about 15 minutes later. It turned over with authority for about 2 seconds and then the starter stopped spinning the motor for a second then it spun slowly and fired up.

    I kind of thought that was odd and my first thought was. Is the battery going bad? Its only 14 months old and has been tendered when not in use.

    Thinking it was just an anomaly I parked it for the day without much further thought. This morning it did the same thing and again when I left work. It turns over just fine and then its as if the starter does not have the power to turn over but eventually it finds away and it starts.

    So my first guess is the original battery even though its only 14 months old and well cared for is starting to go.

    Other less likely possibilities is the starter is weak or some issue with the compression release if it actually has one.

    Its also possible that the battery is still good but is of minimum spec and now that its slightly aged it has a bit of a hard time providing the necessary cranking amps but will continue to operate this way for some time (perhaps years) before one day it just can't turn it over any longer.

    I think I am going to live with it a bit and see how things progress. If it becomes a bit more of a problem I may replace the battery hoping its just that. If its something else I am a bit more lost on what it could be.

    I do welcome comments from other Zuma 125 owners if they have experienced something similar.

    Oh I did check the battery terminals for cleanliness and tightness. Both clean and tight so it was not that.
    #25
  6. Chillis

    Chillis Land Barge Pilot

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    Is it a sealed battery? If not, check water level. Does sound battery related if it cranks quickly and then goes difficult. Or something somehow spiking your compression.

    Checked oil level to make sure fuel is not bypassing fuel system?
    #26
  7. gec343

    gec343 Been here awhile

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    Yesterday, while getting a new tire mounted on my Gold Wing, I took a new Zuma 125 for a test ride. I want one for running around my property, short runs, etc.

    Anyway, the thing quit a mile from the dealership, totally dead. I pushed it back, and the saleman believed it was a dead battery.

    In researching the Zuma 125, ut seems I remember an issue with them not starting after being run in hot weather, then having to let them sit for 15 minutes or so.

    Just went back and read the other posts, so looks like the "not starting" issue has already been addressed.
    #27
  8. topless

    topless Been here awhile

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    There was a recall on fuel pumps for Zuma125s. The symptom of the defective fuel pump is quit running when hot, restart when it cools off. I owned 2 of them one failed at 600 miles the other went at 3600. It happens sooner or later.
    #28
  9. longhaul747

    longhaul747 Been here awhile

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    The Zuma 125 uses a sealed AGM Maintenance Free battery. Usually these hold up pretty well. In fact its not uncommon for people to let these sit all winter and still have juice in the Spring for a solid start. Religious use of a battery tender for these types of batteries is questionable. However it does not hurt and any battery that sits not being tendered will not last as long. A tendered battery could last up to 10 years or longer assuming the charging system on the bike is clean.

    I checked the oil level yesterday and its good and the oil is still nice and clean. So its likely not any sort of hydro lock issue going on.

    I am still kind of going with battery. It no longer puts out enough amperage to turn the motor over during a compression stroke is my guess.

    Thanks for the link!

    A lot of simple tips in that video I have experience with. One of the first things you can do is simply take your Battery Tender and see how it behaves. If it takes a very long time or never reaches a full charge that is a tall tale sign the battery is not healthy. If it reaches a full charge but then goes back to a charging state shortly afterwords that is another sign the battery has issues.

    I do have multimeter and the static voltage should read between 13 and 14 volts if memory serves (I don't check them often). If its much below 13 that is a sign of a weak battery. The best test is to crank it with the multimeter hooked up. If the voltage takes a massive nose dive and obviously fails to start the motor that pretty much guarantees a bad battery. I have had a few batteries over the years that read good voltage but then drop to zero the second you hit the starter button.

    I have yet to fully test my Zuma 125 but might later today. I am naturally thinking since the battery is 14 months old its not the battery but sometimes they fail for whatever reason. The most common is from improper prep at the dealer. Some bikes just eat batteries. Likely inadequate (or over adequate) and/or dirty charging system puts strain on the batteries and maybe a dirty or inadequate ground has something to do with it. I just finished browsing the Zuma forums and it seams fairly common for people to drop a new battery in between new and 2 years old on the Zuma 125. Usually though they are dead completely and not slow to crank. Its possible mine is in the early stages of failure and any day now it will just give up.
    #29
  10. JerryH

    JerryH Banned

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    I rode my Zuma 125 this morning. It was in the mid '90s with 63% humidity. Ran just fine. My problem with all this is that if I am 200-300 or more miles from home and the pump fails, I'm stranded, because of a defective Yamaha part. The scooter is out of warranty, and even if it wasn't, Yamaha does not provide road service. I'm already carrying tools and a spare belt, flat tire fixing stuff, and usually extra gas along with me. Now I need a spare fuel pump too?
    #30
  11. Chillis

    Chillis Land Barge Pilot

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    I bet you could fix the defective fuel pumps by disassembling them and verifying the connection to the electric motor stays constant.

    The Zuma pump issue sounds the same as my Aprilia SR50 R was. Once fixed you have a lifetime of trouble free usage if you don't let fuel go bad in it.
    #31
  12. topless

    topless Been here awhile

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    It was a recall on the fuel pump. Warranty doesn't matter. Give the vin to a Yamaha dealer and see if the recall applies, if it does, they will install the new pump free of charge and it's a new design that doesn't vaporlock.
    #32
  13. longhaul747

    longhaul747 Been here awhile

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    So far I have not had a chance to test the battery. The first test I am doing is called the 48 hour test. That is let it sit for a few days and see what happens when you try and start it.
    #33
  14. k-moe

    k-moe Long timer

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    Be sure to test the voltage regulator as well. Mine failed with just over 1,000 miles on the scooter. The stock regulator does not get much airflow, does not have many cooling fins, and is painted instead of being bare aluminum. In short (lol) it gets a bit too hot, stops regulating, and overcharges the battery.
    #34
  15. longhaul747

    longhaul747 Been here awhile

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    I will check the voltage regulator as well. I just pulled the Zuma out of the garage and tested the static voltage after 48 hours. Static voltage does not tell you much other then the battery is holding a charge. A really bad battery will not hold a charge. The reading I got was 12.94 volts witch is right where it should be.

    Next I will test cranking volts and then test the voltage regulator while my multimeter is hooked up.
    #35
  16. longhaul747

    longhaul747 Been here awhile

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    I did some more testing and from the looks of it the battery and the voltage regulator are very healthy. Cranking voltage never drops below 12 even when the starter hanged for a second. The regulator at idle shows 13.2 volts and never peaked above 14.3 volts. Middle of the road rpm showed about 13.7 volts.

    Only wild card is after the regulator gets hot witch I have not had the opportunity to test yet but on cold start charging voltages look good.

    Interestingly the starter still hangs for a second during a compression stroke but once it gets over it the engine fires right up. Still a small chance it could be the battery but its looking like something with the engine or the starter is a tad weak. Could be connections to the starter as well!

    Asked the service tech at the local Yamaha dealer earlier today. He said everything on the Zuma is marginal and his first thought was the battery. He has never had to replace a starter on a Zuma or anything related in the engine. Its always the battery with those things. Is honest and worth 1 cent opinion was as long as it still starts I would not worry about it. However I should be prepared to replace the battery at some point down the road.
    #36
  17. k-moe

    k-moe Long timer

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    I don't think the regulator will do anything different once it's warm, but it won't hurt to check. If you have a hairdryer you can use that to help it warm up. Getting it too hot will cook the thing, and it won't work correctly even when cold (this is what happened to mine, under normal operating conditions). Since your battery is holding charge, and the regulator output is within specs I think it's time to move on to other things.

    It is possible that the starter clutch is causing the starter to hang up (though not likely). The starter clutch is exposed to belt dust, and can get coated enough that the rollers won't engage properly. That might be worth checking out, but you'll have to pull the variator to get to it.

    Have you checked how much current the starter is drawing while engaged?

    I wouldn't trust the comments that the service tech made. Some things on the Zuma 125 are marginal, but the starter isn't one of those things. A healthy factory starter was truning over my scoot perfectly fine, and I had a higher compression 155cc kit.
    #37
  18. longhaul747

    longhaul747 Been here awhile

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    I have not tested amp draw on the starter yet?

    Any suggestions on how to do this? Would I simply set my multimeter to amps and test at the battery or should I try and go direct off the starter?

    I am currently riding the Zuma on some errands and then over to a friends house for dinner. So far it has started every time except at the peak of compression it almost stops but so far always gets over it and starts.

    Sort of a thump, thump, thump, thuuuuuuuuuuuuuuumm(stop)p, Thump Thump then starts every time. For whatever reason that compression stroke is causing grief.

    I have heard of a few cases when the voltage regulator tested fine when cold but went out of spec when hot. I doubt its the case here though but would be worth checking. I am not planning on heating the rectifier. Just test it after a lengthy ride and see how it reads? Should read much the same.

    The service writer did mention that he has never replaced a starter on a Zuma and highly doubts it was the problem. Pretty much the same thing said here. Its a robust piece apparently. Probably won't bother with the starter clutch until I get a no start situation. Hopefully that happens at home and not in the urban jungle.
    #38
  19. longhaul747

    longhaul747 Been here awhile

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    Yeah its entirely possible. Over at the Zuma forums I found one thread of a person having somewhat similar issues and cleaning the starter connections fixed the issue they were having.

    It is pretty humid here however my scoots are stored in doors. I also don't ride them in the rain if I can help it. So corrosion seems a little less likely in my case but you never know. It really does not take much for it to cause enough resistance to cause starting issues. Sometimes something as simple as removing the connections and re seating them will correct the problem. Now that I know the battery is good its one of the things I plan to check when I have the time.

    Another thing to check now that you mentioned it is the negative ground. Sometimes corrosion here can cause odd problems. Something as simple as loosening the connection and scraping a bit of the bare metal off will solve an issue if this was it.
    #39