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  1. snowbrd84

    No compression with rocker arms torqued

    Tried again today. If I set each at tdc to 0 lash and the 1/2 turn, all cylinders great compression and starts and runs smooth and quiet. Then half the rocker bolts start spinning out. Torquing to 40 ft lb spec leaves half the cylinders worth no compression and barely runs without giving it...
  2. snowbrd84

    Can I use slightly longer push rods than stock on 454 Gen V?

    Could you possibly point me to where you pulled that Gen V length info?
  3. snowbrd84

    No compression with rocker arms torqued

    Can anyone verify spec push rod lengths for Mark V hydraulic tappet? The ones in here are Intake: 8 1/4 Exhaust: 9 1/4
  4. snowbrd84

    No compression with rocker arms torqued

    Yes it's a marine cam. Compression all back up to 150 one those intake valves were loosened. I'm guessing retightening some of them set them too tight once lifters pumped up.
  5. snowbrd84

    No compression with rocker arms torqued

    Thought u was good but fired it up after buttoning up and lifter tick and then popping through the carb again. The cam I took out was .310 lift and this one is stock spec .286. Could that make a difference. Def not 180 out. I have put 10 hours on it before today after the cam swap. It was low...
  6. snowbrd84

    No compression with rocker arms torqued

    I'm going to buy these because torque method doesn't work. Setting valve lash the classic way worked. Just redid it and it started without any popping or other sounds. After setting lash plus 1/3 turn, some would be loose again after cranking to check compression. I basically set them again...
  7. snowbrd84

    No compression with rocker arms torqued

    All the rocker intake rods are same and all exhaust rods are some. Exhaust posts are further outbound, so longer rods I assume. Turns out it was only the intake rockers. I was able to tighten them until they lost compression, then back out a little bit and get 150psi on each cylinder. All...
  8. snowbrd84

    No compression with rocker arms torqued

    This motor is non adjustable - you are supposed to just torque the rocker arm bolts to 40 ft lbs. Intake push rods are shorter than exhaust.
  9. snowbrd84

    No compression with rocker arms torqued

    7.4 454 flat tappet hydraulic. Push rods never left the motor and were labeled by cylinder. Did not soak the lifters but did prime the motor before break in
  10. snowbrd84

    No compression with rocker arms torqued

    Recently replaced camshaft and had 135-145 psi in cylinders 1-7, 180 in number 8 before. Boat still seriously lacks power. New compression test today. 1 145 2 145 3 90 4 0 5 150 6 140 7 0 8 145 If I loosen the rocker arm bolts on a bad cylinder all the way, it goes to 145 ish psi. Tried...
  11. snowbrd84

    Throttle spring on 1981 Mercruiser 120. Courting disaster

    I wouldn't be surprised if the throttle cable has stretched, and someone rigged that up to get it to both seat against the idle screw and then pull all the way to WOT in the other direction. When the cable stretches enough, you can only achieve one of those things, and it's time for a new cable...
  12. snowbrd84

    Throttle spring on 1981 Mercruiser 120. Courting disaster

    The spring does pull forward, but its on the bottom of lever, which rotates the top back to the idle adjustment screw to close. If it is hooked up to the top and pulling away from the idle screw, then someone hooked it up wrong.
  13. snowbrd84

    7.4 carb with Thunderbolt V - Cant get into base timing

    I'll take a pic next time I am out. Need to run through the throttle cable set up adjustments, I just adjusted new one to match old one, but old one had a lot of stretch in it.
  14. snowbrd84

    7.4 carb with Thunderbolt V - Cant get into base timing

    Discovered throttle return spring wasn't connected (rebuilt the carb 2 days ago - hence the reason for adjustments - and this was first time out). Had also replaced sloppy throttle cable which I think needs a little more preload to push lever back in neutral.
  15. snowbrd84

    7.4 carb with Thunderbolt V - Cant get into base timing

    Went back out today to try and set idle. If I get the idle in hear to 650, then neutral revs up to 1200 is. Gave it gas with rmrge engine cover off and this certainly doesn't sound right. See video. Came back and puller port side exhaust elbow to find this, which looks pretty beat.
  16. snowbrd84

    7.4 carb with Thunderbolt V - Cant get into base timing

    The issue is more setting the idle speed and idle mixture on the carb. The Ignition module has to be in Base Timing Mode to disable the Idle Speed Control when doing so otherwise it constantly changes the timing to try and smooth out idle. So you can't go through the standard setup procedure.
  17. snowbrd84

    7.4 carb with Thunderbolt V - Cant get into base timing

    Voltage issue solved. New ignition switch and immediately everything at 14v immediately after start with no fluctuation. I had cleaned contacts on outside but must have been corroded or burned out inside. Still no base timing mode. I'm assuming at this point the Ignition Module is damaged. It...
  18. snowbrd84

    GM EST Distributor Kit and Mercruiser Shift Interrupt Switch

    Thanks! Do you know if that unit has a rev limiter and integrates the existing knock sensor?
  19. snowbrd84

    GM EST Distributor Kit and Mercruiser Shift Interrupt Switch

    Mind posting or pming a link to the one you bought? Pretty sure my Ignition Module is not working right and thinking HEI might be the answer.
  20. snowbrd84

    7.4 carb with Thunderbolt V - Cant get into base timing

    Did another test today, and with the knock module completely unplugged from its harness, there is still 8.5v on the purple/white wire. The merc TB V diagram shows that purple white has 3 ends, the knock module where 8-10 v outputs, the Ignition Module where that signal is received, and the...
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