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  1. #1

    Ultra 150 max rpm 5500

    Rebuilt pump, installed new eye glass seal, having the same problem. Just realized that the middle vacuum valve is not sliding at all. #1 and #3 work fine. Will a simple rebuild fix this? Sorry if this has been discussed before but i couldn't find a similar thread. Also, if i run it like that will i cause any damage? would like to use it this weekend and don't think I’ll get parts in on time.

  2. #2
    btldigger's Avatar
    Join Date
    Feb 2007
    lebanon tn.
    Make sure the f/a adapter ring on the top of the carb is turned right. The slot in it goes up or toward the cylinders. Next try moving the slide up by hand to be sure its not stuck. Next remove the 4 screws that hold the cover over the diaphram. Inspect the diaphram for holes or tears. Be sure the edge is back in its grove so it seals. That should give you some place to start.

  3. #3
    All move freely by hand. although the one that im having problems with sounds a bit differnt when moved by hand. Going to swap around the diaphrams to see if its going bad.

  4. #4
    All move freely by hand and when i blow a bit of air in them. Now i know what you mean by the slot on the adapter ring. I had the slot pointed down...Weird though that's the way i mounted them last year and it worked. I'm going to install carbs today after work and see if that was my problem. Thanks for your help.

  5. #5


    Have you had the plastic cap off the carbs holding the slide assembly? I doubt the problem is the slot. It would still pull a vacuum even turned around. Most, myself included will line them up with the carb but if not they will still work. I would be more inclined to believe you dont have a good seal with the rubber diapragm under the plastic cap. Take the 4 screws off holding the cap and check the o-ring to see if its seated correctly.

  6. #6
    Working like a champ now! Turned the rings with the slots towards the cylinders and all three move together now. I did remove the cap to inspect the diaphram and it looked good, made sure when I reinstalled it that it sat and sealed properly. Thanks for all the help! Because of you guys I had a blast on my ultra this holiday weekend.

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