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  1. #1
    Petty Officer 2nd Class
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    Default Unable to prime-bulb won't firm up

    I am not able to get the primer bulb to firm up. I pump and pump and I hear noise like squeaking or bubbles in it. The bulb almost feels like its having a lot of trouble filling up, as if the fuel line is constricted. Also, after a squeeze, it returns to the original shape very, very slowly.

    Troubleshooting:
    I've installed a new complete fuel line assembly with a new bulb and have the same problem. Then I disconnected the line from the tank outlet and connected same to an external tank. Same problem.

    Next I thought I'd look at the line to motor connector, but I'm not sure what else to look at from here.

    Engine: 1986 I6 115
    Tank: Kracor tank, Model 6-7015, 24 Gal
    Fuel line assembly from Bass Pro, Tempo Brand, (I think, but not sure, cause I'm at work and this has been bugging me enough to post now and not wait until I get home later)
    Full tank of gas


    Please let me know what else I can provide.

  2. #2
    Petty Officer 2nd Class MIKEY*2007's Avatar
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    Default Re: Unable to prime-bulb won't firm up

    I know this sounds dumb but know a bloke that did, on the bulb there should be a arrow this should go in direction of motor not tank, fuel only pumps one way try blowing air in fuel pickup on tank with cap off there might be a blockage also make sure bulb is closer to tank then motor .

  3. #3
    Lieutenant Junior Grade hkeiner's Avatar
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    Default Re: Unable to prime-bulb won't firm up

    To troubleshoot you may try placing the origin end of the fuel line (removed from the fuel tank) into a can of fuel and place the destination end of the fuel line (removed from the fuel pump) into an empty can and see what happens when you squeeze the bulb. Don't include any quick connects/connectors/fittings/thru-hull fittings/etc. in this setup. If the squeeze bulb does not work OK this way, get another fuel line/bulb assembly. If the bulb works ok, then reconnect one end or the other end of the fuel line to see which end is causing the problem and troubleshoot from there. Temporarily installing a vacuum gauge (using a T-connector) at various positons in the fuel line may also help isolate the problem.

    I do not have personal experience with the Tempo brand fuel line/bulb, but I have seen it often strongly suggested by others on this forum that only a Mercury brand fuel line/bulb should be used and that other brands may be #####.
    Attached Images Attached Images
    1996 Mercury 150HP V6 carbed outboard motor and Maxum 1900XR bowrider boat

  4. #4
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    Default Re: Unable to prime-bulb won't firm up

    Thank you for all the great suggestions and the TSB and diagnostic pages. I'll post the results/questions as I test.

  5. #5
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    Default Strange result

    OK, so today when I got home from work I decided to perform some initial investigation and here's the steps I took and the results:

    1. I disconnected the fuel line fitting at the engine. The fuel line was attached to an external 3 gallon tank that is from another boat.
    2. I depressed the center ball inside the fitting and pumped the primer bulb.
    3. Fuel freely pumped into the bulb, through the line and out the fitting. I stopped pumping.
    4. I reconnected the fuel line fitting to the engine.
    5. I pumped the bulb and with the motor cover off, could hear air/noise with each pump. The bulb inflated very slowly as before.
    6. I rotate the engine with the steering wheel so I could listen from the port side this time.
    7. I pumped some more, same result, same noise.
    8. I lifted the 3 gallon tank and placed it in the transom and pumped some more and then the fuel flowed freely and the bulb firmed up.

    I have no idea and I'm not sure anything is really solved. I still plan to perform the diagnostics described above but wonder if anyone had any thoughts about this sequence of events.

    Also, I'm going to inspect the fuel pick-up in the tank to make sure its not leaking anywhere as I read a thread about that being an issue with 1/4 tank of fuel and unable to prime/stalling.

    Have a great weekend everyone!!

  6. #6
    Lieutenant Junior Grade hkeiner's Avatar
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    Default Re: Unable to prime-bulb won't firm up

    I lifted the 3 gallon tank and placed it in the transom and pumped some more and then the fuel flowed freely and the bulb firmed up.

    Are you using a quick-connect fitting or similar when you are switching between the temporary 3 gallon tank and the tank on the boat? Since the problem occurs witht the 3 gallon tank too, the problem may be caused by something common to both setups. Air entering into the fuel line at a quick connect upstream of the fuel bulb is a possibility and the air/noise sound may be an indication of this. This might also explain why the bulb firms up when the tank is higher than the bulb, as the fuel flows downward into the bull and it fills with fuel, the bulb is no longer pumping any air.

    Keep in mind that I am only guessing at this and I not quite sure what you meant when you said "I disconnected the fuel line fitting at the engine. The fuel line was attached to an external 3 gallon tank that is from another boat."

    On my boat, I do not use any quick connects. The fuel hose assembly slips onto the fittings at the tank and the fuel pump without anything in between, other than the bulb and a fuel/water separator filter. I secure the hoses to all the fittings with doubled up Murcury tie-straps. The reduces the risk of air leaks in the fuel line.
    1996 Mercury 150HP V6 carbed outboard motor and Maxum 1900XR bowrider boat

  7. #7
    Admiral j_martin's Avatar
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    Default Re: Unable to prime-bulb won't firm up

    Get a Mercury fuel line and bulb. That thing you have don't have the nads to pull fuel against 1 lb of suction needed to lift it out of the bilge.

    hope it helps
    John

  8. #8
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    Default Re: Unable to prime-bulb won't firm up

    I was looking for the Mercury hose kit and didn't see one at the iboats store or a few competing vendors. Is it pretty much only available from Parts Express online?

    Also, the fittings: When the fuel hose is installed in the boat, there are two screw clamps securing the hose to the out of the water separator, and the only quick connect fitting is the engine connector. However, when connecting to the three gallon tank, I did insert a quick-connect fitting temporarily.

    I'll be at Cabelas this weekend as well, and will look for the Mercury hose.

  9. #9
    Captain mthieme's Avatar
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    Default Re: Unable to prime-bulb won't firm up

    DH - Does the motor not run?
    If it does, any performance issues?

    Mercs are notorious for the fuel pump diaphrams which will cause this, but you should have some other symptoms too...lack of rpm, etc.
    I have the same issue with my Merc 35 but everything -EVERYTHING- has been replaced or rebuilt this season...runs fine so I don't worry about it.

    Nothing is so broken that Government can't make it worse.

  10. #10
    Admiral j_martin's Avatar
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    Default Re: Unable to prime-bulb won't firm up

    Quote Originally Posted by mthieme View Post
    DH - Does the motor not run?
    If it does, any performance issues?

    Mercs are notorious for the fuel pump diaphrams which will cause this, but you should have some other symptoms too...lack of rpm, etc.
    I have the same issue with my Merc 35 but everything -EVERYTHING- has been replaced or rebuilt this season...runs fine so I don't worry about it.
    The primer bulb will not inflate. Either the suction line or screen is plugged, or the primer bulb itself is wimpy.

    He stated that under some conditions, it seems fine, therefore I came to the conclusion that the primer bulb itself was wimpy.

    I almost burned down a nice XR4 with a perfectly good AttWood primer bulb and line. My mechanic wised me up. I'm thankful for him.

    hope it helps
    John

  11. #11
    Captain mthieme's Avatar
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    Default Re: Unable to prime-bulb won't firm up

    It could very well be the bulb.
    Sounds like it's too early in the troubleshooting process to tell for sure.
    He stated "it returns to the original shape very, very slowly".
    His issue sounds exactly like mine earlier this season.
    ...just giving him something else to check...
    Hopefully he'll keep us abreast of what occurs.

    Nothing is so broken that Government can't make it worse.

  12. #12
    Petty Officer 2nd Class
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    Default Re: Unable to prime-bulb won't firm up

    DH - Does the motor not run?
    If it does, any performance issues?


    The motor runs and runs well. I had rebuilt the carbs last season, link and sync, and all was good. Last time out, once the motor was going, it seemed to have a hard time getting to the proper RPMs, but finally, when adjusting the trim, I got going nicely.

  13. #13
    Captain mthieme's Avatar
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    Default Re: Unable to prime-bulb won't firm up

    I assume she starts good too (?).
    Sounds like you're only issue then is a soft primer bulb?
    The one on my 35 never gets hard, but starts and runs great.

    Nothing is so broken that Government can't make it worse.

  14. #14
    Lieutenant Junior Grade hkeiner's Avatar
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    Default Re: Unable to prime-bulb won't firm up

    If air is getting sucked into the fuel line, you have to determine this soon and fix it before running the motor at high RPMs. This type condition will cause lean running of the motor, which may damage the motor at high RPMs. Inserting a short piece of clear hose inline (near the fuel pump and/or near the fuel tank) will let you monitor for air bubbles in the fuel at it passes through the fuel line. If you see no air bubbles, then you can consider other causes, such as a weak bulb as others have already wisely suggested.

    Also, don't overlook the option of using a vacuum gauge to troubleshoot/test the fuel delivery system. These type tests provide more objective information on what is working and what is not working OK. Sometimes a mix of problems makes it difficult to interpret the many and various symptoms, such as what you have described so far, and guess at the exact cause(s).

    Just my thoughts...
    1996 Mercury 150HP V6 carbed outboard motor and Maxum 1900XR bowrider boat

  15. #15
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    Default Re: Unable to prime-bulb won't firm up

    No, no no no...

    Starting is VERY VERY difficult. I got a blister on my thumb from holding and turning the starter key so much!!

    Here's the starting procedure I've used:
    1. Prime until hard
    2. Hold key in, in on position, so enricher can enrich, count of 8 seconds on watch.
    3. In fast idle, crank, crank crank...didn't start
    4. Primer bulb was not hard, pumped it again, tried as best i could to firm it up.
    5. Tried above again and again. Seems that I was able to start by increasing the fast idle to full as the motor was catching. After 40 minutes of trying, finally, the motor started, first very slowly, then it got to 1500 rpm and I warmed up at 1200.

  16. #16
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    Default Re: Unable to prime-bulb won't firm up

    Results of second investigation:

    I found some fuel leaking on the hoses from the fuel pump and both sides of the little inline filter there under the cowl. There are plastic ties on the hoses and I'm thinking I should cut all those off and replace with those tiny 'radiator clamp' screw down style.

    Please let me know if that is the approach I should take. I do think I may have replaced some of these hoses and used the plastic clamps as I think there used to be plastic clamps.

    Would this condition lead to the problems I experiencing?

  17. #17
    Captain mthieme's Avatar
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    Default Re: Unable to prime-bulb won't firm up

    You haven't mentioned the choke. I assume they are functioning properly?
    It's possible that the leaky lines could cause your problem, but I would think it would have to be more severe. I assume you're talking a little wetness as opposed to a steady noticeable leak.
    I'm still thinking fuel pump at this juncture.
    This is a cheap easy thing.

    Nothing is so broken that Government can't make it worse.

  18. #18
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    Default Re: Unable to prime-bulb won't firm up

    Well, I did rebuild the fuel pump during the middle of this year and it was my first one, so maybe I goofed? I have no problem ordering a new rebuild kit and doing it again and maybe that would be a good idea regardless.

    The choke should be working ok and due to operator error, I actually broke a part of the system and had to replace it, so the enricher mechanism is new and the wires are securely attached. I did verify that.

    But, now that you mention it, when I am trying to start, the motor behaves differently if I try to start without pushing in the key vs pushing in the key, so I wonder if I should perform choke/enricher diagnostics?

  19. #19
    Captain mthieme's Avatar
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    Default Re: Unable to prime-bulb won't firm up

    That would explain your starting issue if you found something.

    The fuel pump is pretty simple. I assume you're no stranger to wrenches (?).
    It would be pretty hard to muff up. Although I had some rubber parts last two days in mine - replacement parts were teflon (ethanol ?).

    Like I was saying about my bulb, it's soft but everything is okay: starting, running, etc.

    Nothing is so broken that Government can't make it worse.

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