Bringing Max IV back to life- lack of power issue

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Thread: Bringing Max IV back to life- lack of power issue

  1. #11
    Toys4Me's Avatar
    Toys4Me is offline Master Mudder Toys4Me is on a distinguished road
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    Something I've found especially with the Briggs on climbs. The fuel pickup in the bowl is in the front and if you get enough angle you cant pickup anymore fuel. Your right its not a good feeling when it dies and you have no option but to roll back down. As for bogging down I've found switching to a red secondary spring greatly helps this. What size tires are you running on your Max IV as this can effect the bogging down.

  2. #12
    Noel Woods is offline Master Mudder Noel Woods is on a distinguished road
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    This sounds like the perpetual issue with cheap mechanical fuel pumps when you also factor in fuel lines going above the fuel tank especially when going up hill. I would try a low pressure electric fuel pump (1-3 psi) which are relatively inexpensive. Tie it into the ignition switch so that it only works when the ignition is on. It won't hurt to also keep the mechanical fuel pump connected. Between the mechanical and the electric pump you should have a good supply of fuel.

    I did the above trick on an old classic vehicle and the truck runs so well now it almost seems like it is fuel injected.

    What's the compression on the cylinders? The little B&S motors will sometimes wear themselves out quickly when they are abused, and that may have been caused by the prior owner's lack on maintenance.

  3. #13
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    I have the small 21" tires to fit the tracks that are not installed. Haven't done a compression test yet. I'll grab a low pressure fuel pump and see if that happens. I've heard lots of talk about the red spring. I'll get that ordered.
    To have adventures, you must go places where adventures can happen.

  4. #14
    Noel Woods is offline Master Mudder Noel Woods is on a distinguished road
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    I have the red spring kit on all my t20 equipped machines, its the best way to keep the machine in the low power band, you will lose some on the top speed though but it's marginal.
    Your machine should run well with the small tires and 18hp motor. The 18 is as small an engine that should be in a Max 4 though. If you upgrade ever, I would switch to a Kohler.

  5. #15
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    Where's the best place to get a red spring?
    To have adventures, you must go places where adventures can happen.

  6. #16
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    Just ordered a red spring from max6x6
    To have adventures, you must go places where adventures can happen.

  7. #17
    hipowerone's Avatar
    hipowerone is offline Master Mudder hipowerone is an unknown quantity at this point
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    Verify that you have spark to both plugs

  8. #18
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    Spent some time today, before eating too much, and found the drive belt was pretty loose (two inches of movement) so I shimmed the engine and brought it to an inch of deflection. What's the proper belt width? This one looks skinny, (measured just over an inch wide)like has some room on each side of the top clutch when engine is off. I reduced the droop in the fuel line and then was messing with the plugs to see if they were both working as suggested and the rear hood shocked me then I noticed is was cracked pretty bad. I fixed that and it seems to be running much smoother now. Taking it hunting tomorrow and that will be the test if I've actually made some headway. Fingers crossed!
    To have adventures, you must go places where adventures can happen.

  9. #19
    hipowerone's Avatar
    hipowerone is offline Master Mudder hipowerone is an unknown quantity at this point
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    Your issue with "running fine" on level ground but no power up hill sounded like my recent problem where I discovered one plug wire was "burnt" and no spark. Also could be the belt as well. I am not sure on the MAX IV, but on the MAX II, the belt should be 1 3/16 in wide. Please note, I have spoken with a MAX technician and he states that while the specs call for 1 3/16" width, most belts shipped are undersized, closer 1 2/16". But 1" does sound way too narrow. Hopefully someone with a MAX IV will chime in with correct belt replacement number and correct width.

  10. #20
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    Great input and yes the belt size and part number for the proper one would be great as I'd like to have a spare handy.
    To have adventures, you must go places where adventures can happen.

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