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  1. #1

    Default 85 Mercruiser 140 fuel issue! Need some help

    Hey guys I am new to the forums. and I am in need of some help. I have a mercruiser 140 I have been having issues with. A few weeks ago I was on the lake and boat died and wouldnt start was not getting any fuel to the carb. Naturally I thought the fuel pump went out. I got my new fuel pump in on friday and installed it sat. after priming the system boat started right up and run for a hour hooked up on the muffs. I took the boat out today and ran great for 3 straight hours. We stopped the boat and anchored out in a cove for some swimming. after about a hour of sitting we started the boat it idled for about a minute and died. It would not start again. checked fuel line and no fuel to carb. checked the fuel filter on the pump it was clean. Im tired of getting stranded!

    My wife is ready to kill me. I know its gotta be something simple but i have no idea yet. Any and all help would be greatly appreciated.

    Also I was checking my prop and i found a little bit of slop not up down but in and out on the prop shaft. is this normal slop or should i be looking at new bearings in my lower unit soon? The slop is about 1/16th to a 1/8th of a inch in and out.

  2. #2
    Cadet
    Join Date
    Jul 2011
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    Detroit
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    Default Re: 85 Mercruiser 140 fuel issue! Need some help

    How did you prime your fuel pump?

  3. #3

    Default Re: 85 Mercruiser 140 fuel issue! Need some help

    added fuel to the carb and to get it fire. So not really priming the pump just getting motor to start to get the pump to build enough pressure to prime the system. much easier to do than crank crank crank crank and burning up the starter. i did pour a small amount of gas in the fitting on the pump that goes from the pump to the carb.

  4. #4

    Default Re: 85 Mercruiser 140 fuel issue! Need some help

    I checked the check ball in the fitting on the tank and it looked good and seemed to be working the way it should. also checked the filter going down into the tank it was clean, Anyone Please Help point me in a direction I am at a loss here.

    I also found a forum post about the slop in the prop and seems normal. Now if I can just get some help with my fuel issue.

  5. #5
    Captain
    Join Date
    Mar 2009
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    Central CAL
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    3,711

    Default Re: 85 Mercruiser 140 fuel issue! Need some help

    Is there fuel in the tank?
    When will people learn that impellers require regular
    replacement and are not drive it till it pukes items?

    1984 Regal Medallion 195
    3.8 V-6 with the dreaded
    OMC Stringer Drive.
    2003 Avalanche w/Hypertech

    If it ain't fixable - don't break it!

  6. #6
    Petty Officer 1st Class reddogg's Avatar
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    Default Re: 85 Mercruiser 140 fuel issue! Need some help

    Is your tank vented properly? Maybe trash in the tank?

    Red
    Honor, Courage, Commitment.

  7. #7
    Petty Officer 1st Class
    Join Date
    Oct 2010
    Location
    Florida
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    302

    Default Re: 85 Mercruiser 140 fuel issue! Need some help

    You need to find out where the problem is originating. When you can't get fuel to the carb, take the line off of the pump at the "in" fitting and attach a primer bulb - see if any fuel will come out. If it isn't coming out then take the hose off at the next fitting and keep trying with the bulb. This happened to me while I was underway and it was a jammed check ball, slammed it down to loosen it and it was fine. You may have some junk in your tank that is getting sucked into the intake line and when your engine dies-it falls back into the tank.

    If you take the line off the pump and it is fine, then it is your fuel pump forward you need to worry about.

    Also, have you checked your float level in the carb???

  8. #8
    Chief Petty Officer
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    Ontario, Canada
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    Default Re: 85 Mercruiser 140 fuel issue! Need some help

    i had the same problem i had to pour fuel down carb to start i got to the point and put a primer ball on and still could not get fuel i checked the anti syphon valve and it seemed to work fine put the primer ball right at the antisyphon valve and still could not get fuel replaced valve and all worked good. start from the beginning clean tank replace inline filter if you have one replace antisyphon valve change fuel filter and make sure you have no water in the fuel do you have a fuel/water seperator also make sure your fuel line is not cracked

  9. #9

    Default Re: 85 Mercruiser 140 fuel issue! Need some help

    yes there is fuel in the tank.
    When this happened to me at the lake I removed the line to the fuel In fitting on the fuel pump and it was dry. I removed fuel pump and manually activated the pump and the remaining fuel sprayed out of the "out" fitting. I did notice that my clear tube running to the carb is partway clogged but i can still blow through it. The check ball responded well and when i blew through it it made a fluttering sound like I was blowing in spurts. this kinda concerned me a little.

    dn010 If it was junk in the tank wouldnt it stall out while driving ? It only does this after it sits for a while. And if it pumps fine with a bulb down by the tank and i get fuel out the in fitting. what could it be from the pump upwards that would make the pump loose prime?

    is there any larger ports to inspect the tank through other than the sender? its about a 2.5" whole.

    I will be replacing the fuel line on fri and trying the primer bulb. the bad thing is is this seems to only happen when the motor is under a load for a period of time. I could not dublicate this problem while hooked up to the muffs. So I may be conducting diagnostics at the lake. I will build up my rowing arm!
    I appreciate all the input guys atleast I now have a direction to go in.

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