Thread: Vmax surging

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  1. #1
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    Vmax surging

    Just replaced fuel pumps, plugs, water/fuel separator on my 2008 150 V150TLR. The other fuel filter looked pretty good so I left it in there. Took it out today again and still having issue with engine either not getting full rpm and speed or when it does it cuts out and drops dramatically. Idling and accelerating is fine, only having the issue when I’m trying to open it up.

    One other thing I’m having an issue with is my throttle handle doesn’t want to stay down, it slowly creeps back to the neutral position when I let go of it.

    Any advice would be greatly appreciated. Hard to find many people that know a lot about these motors.

  2. Member cwilt's Avatar
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    #2
    How is the condition of the fuel line. Do you have a filter on your fuel pickup in the tank? Also look at the fuel bulb. I had an issue on a different motor that the bulb would collapse and starve the motor, it would shutdown (but not surge). When was the last time the carbs were rebuilt? Might need a float adjustment.

    Also from your other post, if your plugs are all sooted up, you need the check your oil pump adjustment. What oil are you using. I run the yamalube 2m, which is known to cause some carbon buildup. I also run the ring free which seems to help.

    As far as the throttle goes, there is an adjustment screw at the base of the throttle. I dont think its supposed to stay at wot without being held there. Do you have an owners manual? I think the directions for the adjustment of it is in the manual. If you need some pics of the maintenance manual, DM me and i will send them to you.
    Last edited by cwilt; 12-26-2021 at 11:12 PM. Reason: Add info.
    2008 Ranger 178VX
    150 Yamaha V-max

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    #3
    Quote Originally Posted by cwilt View Post
    How is the condition of the fuel line. Do you have a filter on your fuel pickup in the tank? Also look at the fuel bulb. I had an issue on a different motor that the bulb would collapse and starve the motor, it would shutdown (but not surge). When was the last time the carbs were rebuilt? Might need a float adjustment.

    Also from your other post, if your plugs are all sooted up, you need the check your oil pump adjustment. What oil are you using. I run the yamalube 2m, which is known to cause some carbon buildup. I also run the ring free which seems to help.

    As far as the throttle goes, there is an adjustment screw at the base of the throttle. I dont think its supposed to stay at wot without being held there. Do you have an owners manual? I think the directions for the adjustment of it is in the manual. If you need some pics of the maintenance manual, DM me and i will send them to you.
    The previous owner said he went over the carbs this past summer. Now did he do something to them wrong I don’t know. He was running the yamaha 2m oil, with ring free. Will say when I replaced the plugs the other ones were sooted up pretty good. There’s no other filters is see except for the fuel/water separator and the in-line fuel filter. I will say when I took apart one of the old fuel pumps I did see a little piece of plastic up in there from the inner lining of a fuel line.

    Although I replaced a lot of this stuff I’m still having the same issue. And when I poured the gas from the canister filter into a glass jar it looked fine to me, no water inclusion or sediment. I know some one that said they had an issue with the anti siphon valve causing this issue.

    The weird thing is I’ll have some times where it would open up properly but most times not. Also, I just performed a compression check and all the cylinders look good (112-115 range).
    Last edited by bigfoot17; 12-27-2021 at 07:07 AM.

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    #4
    So I ran the boat today with a portable gas tank to try and eliminate some of my problems. The engine ran like a top! Didn’t miss a beat. Now I know it gotta be coming from the the gas tank and the fuel line coming from it. At least I know it’s not the carburetor.
    Last edited by bigfoot17; 12-29-2021 at 08:23 AM.

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    #5
    Quote Originally Posted by bigfoot17 View Post
    So I ran the boat today with a portable gas tank to try and eliminate some of my problems. The engine ran like a top! Didn’t miss a beat. Now I know it gotta be coming from the the gas tank and the fuel line coming from it. At least I know it’s not the carburet.
    That's cool! Let us know what the final gif was.. thanks!

  6. Member cwilt's Avatar
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    #6
    Quote Originally Posted by bigfoot17 View Post
    So I ran the boat today with a portable gas tank to try and eliminate some of my problems. The engine ran like a top! Didn’t miss a beat. Now I know it gotta be coming from the the gas tank and the fuel line coming from it. At least I know it’s not the carburetor.
    2008 Ranger 178VX
    150 Yamaha V-max

    GO Fins!!!

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    #7
    Well I made a mistake saying the engine was running good off the portable tank. First time I tested it I didn’t have a strap to the portable tank so it was a little difficult with my setup. I didn’t really run the engine that long and in the time I did it seemed good but i had to test it one more time with the test tank and I unfortunately ran into the same issue. So I’m guessing the problem is from the bulb up. The only thing I didn’t change out on the test was the line coming from the bulb to the motor.

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    #8
    Water Separator Filter
    If you pump the primer bulb does it stay firm or goes flat? I had replaced my water-fuel separator with a new filter empty of gas installed it back onto the separator housing. I then primed the bulb and it would not stay full of gas. Took to the lake it would idle fine. When trying to get on plane it would stall and pumping bulb helped to get on plane but then would fall flat. Now when i replace the filter i fill the new filter with filtered-fresh gas half full and screw back on.

    VST Tank filter (inside vst silver tank)

    Has that filter been replaced? If so did you make sure the small o-ring is still between the new filter and underside of the tank housing? Make sure the small pin for the float is centered and also the float moves freely up and down inside the vst tank before reassembly.

  9. Member bassinman215's Avatar
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    #9
    Your motor doesn't have a VST, as it's carbed.

    Almost wondering if there may be an issue with the floats in the carburetors. Bowls running empty and not being able to keep up because of a sticking needle. Others that are smarter than me - does that make sense? I've been PM'ing back and forth with the poster on this boat and it's throwing me for a loop as well.

    Do any of the plugs look different from each other - may help to diagnose which carb, if any, is acting funny.
    Wishing I was Fishing

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    #10
    Quote Originally Posted by bassinman215 View Post
    Your motor doesn't have a VST, as it's carbed.

    Almost wondering if there may be an issue with the floats in the carburetors. Bowls running empty and not being able to keep up because of a sticking needle. Others that are smarter than me - does that make sense? I've been PM'ing back and forth with the poster on this boat and it's throwing me for a loop as well.

    Do any of the plugs look different from each other - may help to diagnose which carb, if any, is acting funny.
    Gonna take a look at the sparks next time I get a chance. Bassinman, you have been very helpful so far. I know I PMed you about this but might as well post what I did notice for others.

    So I looked at the same exact year and model motor a friend of mine has. Notice that mine has a non-OEM fuel line coming off the VERY FIRST ‘T’ fitting after the small fuel filter. Not the one come from the filter to the first T fitting but the the hose downstream of that fitting goin to the bottom fuel pump. The hose is just a normal black fuel line hose that’s at least 8” long, it’s only supposed to be a short piece about 3” at best. Not sure why it’s set up like that but wonder if that would cause issues.

    Also noticed a tiny bit of gas that may be leaking from one of the carbs when my motor is trimmed up and not in use.

  11. Member bassinman215's Avatar
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    #11
    I can't see little differences in fuel plumbing causing your issues. As long as it has enough fuel going to the pumps and from the pumps, it shouldn't matter.

    On the gas dripping - does it get worse if you use the bulb primer? One of the symptoms of a carb needle/float system not sealing properly is that it will leak gas. The gas leak wouldn't cause your wide open issue, but if it's starving for gas and running dry at high demand, that could. Pay extra attention to what the plugs look like on the leaking carb.

    I'm convinced your issue is fuel related. You've eliminated just about everything boat side, now its a matter of troubleshooting motorside.

    If it makes you feel better, when I had my issue a few years ago, I started motorside and ended up fixing it boatside...
    Wishing I was Fishing

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    #12
    So, I have a 99 P200 TLRX. It had a "hard surge" issue and lack of power at certain RPM, but idled like a charm. I originally thought it was fuel related, pulled plugs, checked compression, resynced carbs, fuel pumps, fuel/water filter, engine filter and yes, even the ball valve..... All helped, but in the end it was a cracked reed valve that caused the problem. Bought the motor on auction for a steal, was shipped from FL and the lowest intake reed block was starting to rust (probably salt water left in shipment horizontally), also where the cracked reed plate was. I replaced with Chris Carson reeds and stuffers and she runs 150X better...
    One trick you can try is with the breather off, use your hand to cover the face of each carb one at a time, slightly rev up the motor, then take your hand off. Three things you should notice: Significant suction, residual fuel on your hand and often, if there is some blockage in the high speed jets, it can free this up. This can be repeated several times if necessary, just try to get a good seal on the carbs. In addition, with the breather off, it's worth spraying some carb cleaner while she's running.... If you get to the point nothing else is working, taking the carbs off gets a view into the intake and the reeds (with a flashlight). Best of luck man.

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    #13
    Quote Originally Posted by Smallie_Hawgin View Post
    So, I have a 99 P200 TLRX. It had a "hard surge" issue and lack of power at certain RPM, but idled like a charm. I originally thought it was fuel related, pulled plugs, checked compression, resynced carbs, fuel pumps, fuel/water filter, engine filter and yes, even the ball valve..... All helped, but in the end it was a cracked reed valve that caused the problem. Bought the motor on auction for a steal, was shipped from FL and the lowest intake reed block was starting to rust (probably salt water left in shipment horizontally), also where the cracked reed plate was. I replaced with Chris Carson reeds and stuffers and she runs 150X better...
    One trick you can try is with the breather off, use your hand to cover the face of each carb one at a time, slightly rev up the motor, then take your hand off. Three things you should notice: Significant suction, residual fuel on your hand and often, if there is some blockage in the high speed jets, it can free this up. This can be repeated several times if necessary, just try to get a good seal on the carbs. In addition, with the breather off, it's worth spraying some carb cleaner while she's running.... If you get to the point nothing else is working, taking the carbs off gets a view into the intake and the reeds (with a flashlight). Best of luck man.
    I really appreciate your feedback. You gave me another issue that it could be that I really never thought.

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    #14
    I had something like this happen when I had a 08 zx190. It had me and the local mechanic stumped, it took us months to figure it out. I'm not saying this is your problem but mine was in the primer bulb. I changed it out and never had an issue again

    For no more than what they cost I'd start there and hope for the best. If thats not it I would check the fuel lines

    Good luck

  15. Member cwilt's Avatar
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    #15
    Did you get it figured out?
    2008 Ranger 178VX
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    GO Fins!!!

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    #16
    Quote Originally Posted by cwilt View Post
    Did you get it figured out?
    Due to the weather and being able to get it into the garage to work on it I haven’t had the chance but I’m itching bad to pull the carbs and start cleaning them up. Seems a lot of people like using the ultrasonic cleaners for this part. I do have a factory service manual for this particular outboard so hopefully that proves to be helpful. Not sure if there anything in particular I should know before I start. I will definitely post as I try to figure it out.

    I did see the one gentleman suggested inspecting the reeds valves too. That’s something else to look over too.

  17. Member cwilt's Avatar
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    #17
    Couple tips for ya, make 100% sure you set the float hight correct. I messed up one and when i pumped the fuel bulb, fuel leaked from the middle carb. I used carb and choke cleaner when i rebuilt mine. I rebuilt mine with all new parts, floats, needle valves, and gaskets. So no cleaner touched any plastic or rubber parts. Carb cleaner has a tendency to dry out rubber (tip of needle valves).
    Good call on reeds. Yamaha uses metal reeds. They can crack. I am fortunate to only be a couple miles from chris carson marine. I installed his fiberglass reeds. 3 years so far and no issues yet. You can also pick them up at hydrotec marine. If a metal reed goes it could cause some damage. Thats the only reason i went with fiberglass reeds. Your also going to want to use locktite when you assemble the reed cages, dont want screws coming loose. Make sure you have all the gaskets for the intake. Another thing that helped was i took alot of pictures. Lots of oil lines and vacuum lines feeding the carbs and the sides of the block/intake manifold. The pics helped alot.
    All in all, it was not that hard of a job. The reward was the best part...its been running like a champ! Good luck and if you need any help you can find me here.
    2008 Ranger 178VX
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    GO Fins!!!

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    #18
    Change all your fuel line. From the inlet under the hood to the tank. I had a similar issue. Turned out to be a couple soft spots in the fuel line. When I would give it the gas kinda hard the soft fuel line would collapse then open cause a short fuel starvation.

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    #19
    Going to be starting to work on this again soon, now the weather is starting to warm up a bit. By chance is there anyway this can be an electrical problem? Don't think it is but never know. Like maybe a bad coil or something.

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    #20
    Quote Originally Posted by cwilt View Post
    Couple tips for ya, make 100% sure you set the float hight correct. I messed up one and when i pumped the fuel bulb, fuel leaked from the middle carb. I used carb and choke cleaner when i rebuilt mine. I rebuilt mine with all new parts, floats, needle valves, and gaskets. So no cleaner touched any plastic or rubber parts. Carb cleaner has a tendency to dry out rubber (tip of needle valves).
    Good call on reeds. Yamaha uses metal reeds. They can crack. I am fortunate to only be a couple miles from chris carson marine. I installed his fiberglass reeds. 3 years so far and no issues yet. You can also pick them up at hydrotec marine. If a metal reed goes it could cause some damage. Thats the only reason i went with fiberglass reeds. Your also going to want to use locktite when you assemble the reed cages, dont want screws coming loose. Make sure you have all the gaskets for the intake. Another thing that helped was i took alot of pictures. Lots of oil lines and vacuum lines feeding the carbs and the sides of the block/intake manifold. The pics helped alot.
    All in all, it was not that hard of a job. The reward was the best part...its been running like a champ! Good luck and if you need any help you can find me here.
    How was the job of replacing the reeds? How long did it take you?

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