Logo
Click for Honda Manuals, Parts and Model Guides!
Results 1 to 10 of 10
  1. #1

    Post Honda bf 40 loses power after 30 sec on plain

    Hi
    I have a 2007 honda bf 40 with carburatores
    First I had an electrical fault because the cable for the power start was rotten out in the main power connector, that took a while to find
    The engine starts exellent, runs fine on idle but once it gets to plain after aprox 30 sec it loses power and starts working on minimum but the engine starts shaking, after lowering the gas back to neutral it works fine

    it does not go into limp mode because that lowers rpm from 6000 to lets say 3000
    this is complete power loss and it allows me to get back to plain instantly and then over again

    no warning lights came on, oil pressure light is green and the overheat light stays off, I dont know if any warning sounds come on because my speaker doesnt work
    I checked thermostat, even tried without it, water on the tell - tale is normal warm, not hot
    checked fuel pressure

    I would be grateful for any advice, please help
    Last edited by MarkHonda; 09-23-2021 at 11:06 AM.

  2. #2
    Join Date
    Nov 2016
    Location
    Nottinghamshire, UK
    Posts
    35

    Default Re: Honda bf 40 loses power after 30 sec on plain

    Hi,


    Whilst I don’t have any experience specifically with the bf40 I have had many motors that have carburettors.


    The first thing I would do is take the carburettors off, strip and clean them. Specifically, the jets, I suspect you have a blockage. Clean out the jets using compressed air, don’t be tempted to poke anything through the small holes.

  3. #3

    Default Re: Honda bf 40 loses power after 30 sec on plain

    I'll try that first
    Could A dirty carb show those simptoms? It seems like clock wise precision, it seems the same every time

    I am worried that it could be maybe something electrical

  4. #4

    Default Re: Honda bf 40 loses power after 30 sec on plain

    Sounds like a fuel issue here as well, but it could be anywhere. SOMETHING is allowing air to be sucked into the system or restricting fuel flow causing the engine to starve when fuel demands are no longer met. A plugged/shut off fuel tank vent for instance, would act the same way. A tell tale there would be the primer bulb collapsed/sucked dry. When it does this, you could check that primer bulb, and if it's NOT collapsed, try pumping it to see if that improves the performance (hopefully you'll have somebody giving you a hand here!). You mentioned you "checked fuel pressure". How was that done?

  5. #5

    Default Re: Honda bf 40 loses power after 30 sec on plain

    I tried with another fuel tank that i know for sure is good and I tried pumping the primer bulb while driving, same effect
    I didn't follow up the fuel sistem up the motor
    The primer bulb had pressure but i did have to pump 2 3 Times for it to be totaly hard

    If it is an air leak somewhere these are a nightmare to find

  6. #6

    Default Re: Honda bf 40 loses power after 30 sec on plain

    RE:sucking air, generally if they are sucking air it's at either end of the fuel line, and that area will be wet with gasoline as a rule, or maybe a fresh fuel stain if it's been sitting. The other places might be a cracked/broken fuel filter, or possibly the pick up tube inside the fuel tank, but you've already eliminated that with the tank change. It's not too unusually to get 2-3 squeezes on that primer bulb when the motor is running right.

  7. #7

    Default Re: Honda bf 40 loses power after 30 sec on plain

    I'll check those places for any fuel stains/leaks
    Is there anything else I could check that could cause this issue?
    Did you ever hear about these simptoms?

  8. #8

    Default Re: Honda bf 40 loses power after 30 sec on plain

    I go with easy stuff first. If what we've already talked about doesn't produce anything, it'll be time to get into the carbs.

  9. #9

    Default Re: Honda bf 40 loses power after 30 sec on plain

    So you definetly think this is fuel related problem

  10. #10

    Default Re: Honda bf 40 loses power after 30 sec on plain

    Not a doubt in my mind....

Similar Threads

  1. Replies: 4
    Last Post: 07-24-2020, 05:43 PM
  2. Honda BF8D loses power and stalls at full throttle
    By NHfisherman in forum Honda Outboard Forum
    Replies: 6
    Last Post: 07-27-2019, 12:16 PM
  3. 2006 Honda 2 HP skips or loses power
    By Gjkelley31 in forum Honda Outboard Forum
    Replies: 4
    Last Post: 06-20-2018, 07:37 AM
  4. Replies: 3
    Last Post: 08-08-2015, 01:25 PM
  5. Volvo Penta AQ205 431 No power No plain
    By rafael_luna in forum Volvo Penta Gas Archive
    Replies: 4
    Last Post: 07-05-2009, 10:45 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •