Page 1 of 2 12 LastLast
Results 1 to 10 of 15

Thread: Daycruiser motor help

  1. #1
    Just bought a v-drive daycruiser and took it out for the weekend. Everything ran outstanding and we put at least 80 miles on the boat. The one and only problem I am having is a stumble when getting off an idle. The motor runs strong at all ranges, it just stumbles after the velvet drive is shifted into gear and the accelerator is slightly moved forward. I just pump the throttle once up and back then up again and it takes off great. I would rather not have to do this. The motor is a recently rebuilt BBC mildly hopped-up. A new MSD distributor, 6al box and blaster 2 coil. Also has a new double pumper Demon carb on it. I timed it at 32 degrees.
    I havent yet looked into it closely, and just thought I would see if anyone here has ran into the same problem before...maybe it would narrow my search. I'm suspecting the problem is somewhere in the accelerator pump set-up. Although it works just fine, it may be too much or too little. Also, is there some vacuum type connection between the velvet drive and the motor? I've built a few motors along with my race motors myself and havent encountered this problem since they are set-up from the start. But since I dont know whats in the motor its going to be a little of a guessing game till I get it figured out.

  2. #2
    spectras only
    Kurtis , if you have your Demon's primary bowl towards the stern [v-drive setups are diff from jets], I would install the jet extensions [available at any speedshop that sells holley carbs] and make sure you have 30cc primary ,50cc acc pump on the secondary bowl.I think the demon carbs are the same as holleys other than the bowl shape .Demon's bowls were exactly the same as holleys originally and they had to change them to avoid lawsuits ,I think.

  3. #3
    I had thought of that, but the carbs are full to the levels with fuel. They have a sight glass on the side and stay up even when it stumbles. It does this on the slightest or hardest acceleration.

  4. #4
    Senior Member
    Join Date
    Jun 2009
    Sounds like an accelerator pump issue to me. Is the primary acc pump squirting properly?

  5. #5
    What size Demon do you have? If it is an 850, make sure that it has annular boosters. If not, send it to Demon and they will change them for you at a reasonable price. The demon carbs flow high numbers. A 750 might be a better application for your engine/appication. I experienced what you are going
    through. Hope this info helps.

  6. #6
    Got to agree with Rexone, check accelerator pumps, may need to go up one size!.

  7. #7
    Will check those. I believe they are the 30cc pumps.
    What still seems to confuse me is that I can shift it into gear and just tap the throttle forward a little. It will then stumble unless I accelerate above the rpm range that is just above the idle.
    Is there any kind of link between the velvet drive and the motor at all?

  8. #8
    Terminal Velocity
    Check out this at Holley. May be a Demon but the principal is the same...
    Sounds to me like maybe a change in the squirter may be in order.

  9. #9
    Rex and Gofast are on the right track. I have a Hallett v-drive cruiser with a 850 Holley. We tuned it on a dyno etc. but in the boat it would stumble a little on take off. I just started increasing the accellerator pump nozzles a couple of sizes at a time. With a lot of early morning river time and a pad of paper I got the boat to leave from a dead start without a problem.

  10. #10
    I have noticed a delay in the accelerator pump when the throttle is touched. This is where I suspected the problem is, though I havent looked into it yet. Will look at that first on Thursday when we take it out.
    Always pays to ask first. Thanks SK48, I figured others had the same problem with the same set-up before.

Page 1 of 2 12 LastLast

Similar Threads

  1. Looking for Daycruiser
    By NautiII in forum Jet Boats
    Replies: 0
    Last Post: 02-06-2007, 02:50 PM
  2. Replies: 1
    Last Post: 06-13-2005, 03:18 PM
  3. Daycruiser....?
    By Kindsvater Flat in forum V-Drives
    Replies: 17
    Last Post: 06-03-2005, 06:52 AM
  4. looking for a daycruiser 21-24
    By jstwkd in forum Jet Boats
    Replies: 26
    Last Post: 09-12-2004, 07:33 PM
  5. 21-24 daycruiser
    By jstwkd in forum V-Drives
    Replies: 11
    Last Post: 09-07-2004, 10:02 AM

Posting Permissions

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