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Thread: Crossflow build

  1. #46
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    Quote Originally Posted by Fastbass88 View Post
    stock with bathtub heads was 125lbs I'm thinking it'll be 150ish but need to install exhaust before I torque down heads which will be later this week. Running 93, maybe 95 oct for the first tank. Would like to use 91 but will see.
    use the primer when slowing down as thats when you can detonate a xflow engine thats close
    Last edited by powerabout; 06-28-2020 at 11:47 PM.

  2. #47
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    That's a good idea, was going to turn on the primer circuit manually about 50% for the first couple runs. Always start rich but I have no jets for these carbs. Think the 135 carbs have either 61 or 63c in them. Any aftermarket sources for jets?

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    Got everything installed, had the first start up on the muffs and idles well. Hesitates when you hit the throttle but will see what it does under load. My engine only has the adjustable holes for the timer base shaft, not the threaded rod like most v4's. Was on the middle hole I moved it back to the most rearward hole to take off about 4deg timing. Forgot the timing light but will do an initial timing check with the reeves method.

    Is there any other way to get more timing adjustment if needed? Only other thing I see is the eccentric screw on the linkage but I doubt that will make more then a 2deg change.

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    Can you post a photo of that arm and throttle pickup

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    Quote Originally Posted by Fastbass88 View Post
    That's a good idea, was going to turn on the primer circuit manually about 50% for the first couple runs. Always start rich but I have no jets for these carbs. Think the 135 carbs have either 61 or 63c in them. Any aftermarket sources for jets?
    What sizes are you looking for.
    LETS GO BRANDON.... LETS GO BRANDON

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  6. #51
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    Click image for larger version. 

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    I'll grab a pic next time I'm at the boat, this is what the timer base rod linkage looks like.

    I'm not sure yet, haven't taken the boat out to do plug chops and primer trick. Read some posts of carb swaps but no way of getting close to ideal range off forums with all the different year carb configs and motor mods. If anything I think it might be lean but who knows at this point.

    If you just look percentage wise of high speed jet size to venturi, current 1 3/16 have 56c so increase the throats to 1 5/16 that's 25% bigger. That math comes to 70c jets which seems to large.

  7. #52
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    The adjustment is on the thumbwheel on the curved throttle actuator
    You are looking at the throttle cable side.
    Think about when the timer base moves how does it move the carbs
    Be aware that 88 system was designed to open the carbs and run with retarded throttle for emission reasons.
    IMHO set it up so throttle closed at idle and then your idle timing is your idle speed adjustment
    Last edited by powerabout; 07-08-2020 at 09:11 PM.

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    Click image for larger version. 

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    Thats what I'm working with. Where the thumb wheel usually is I have 3 holes to choose from. Then the eccentric screw in the cam fine tunes the timeing. Am thinking of 3d printing custom blocks so I have a wider range to tune from. I can probably get down to 22-24deg total advance as it stands.
    I could back the thumb wheel off to the carbs and make the cam start earlier increasing timing but that does nothing to change my max advance. Just lowers the spread from start to finish.

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    check if your 135 parts will fit??

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    That's a good idea didnt think of that since it has the old style linkage but worth a shot. Plan was to transfer stator and rectifier from 135 since its 12amp system compared to 6 on the 88.

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    Had boat out this weekend, worked advanced timing up to approx 24deg and may increase it some more. Jetting is perfect just a tad on the rich side on the high speed but thats where I want it anyway. No problem idling around scanning areas with the sonar.

    Having problems with the tach, reads correct on the lower rpms but the higher it revs the more out of wack it is. Replaced the rectifier already didnt seem to help(old one melted itself down). Did manage the get 48mph @5000rpm which is what the 88 did stock so bit more timing should be in the cards. No sign of deto and plugs look really nice.

    Fast idle lever is useless so have to take apart control box, also won't let me shift into reverse. All in all its coming together.

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