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Thread: 1980 90HP Mercury Question

  1. #1
    gigamurph
    OK; settle down and let's stifle that laughter! Are there any old school mechanics or whomever that can tell me what the gear ratio is on my dinosaur? I have had no luck in my manuals or at the Merc site.

  2. #2
    Tom Brown
    I think it's 2:1 but I don't have my Mercury manuals handy. I will be able to tell you Wednesday evening if someone else doesn't give you a solid answer first.
    My inline 6 is 2:1 but it's a 1500.

  3. #3
    You Te
    Hey I know, how about turn the fly wheel by hand and do some counting?
    You Te

  4. #4
    Tom Brown
    You Te:
    Hey I know, how about turn the fly wheel by hand and do some counting?
    You Te Next you'll be telling us how you can watch one channel while taping another.

  5. #5
    gigamurph
    You Te:
    Hey I know, how about turn the fly wheel by hand and do some counting?
    You Te I was gonna say "TURN THIS!" but that would be rude! Thanx; was tryin' to do it an easier, ie: lazier, weay.
    wink

  6. #6
    gigamurph
    Thanx TB. How ya feelin'? Doin' OK?

  7. #7
    77charger
    Hey gig youtee can also make that 90 hp a 340 hp screamer.Imagine how fast you can tow my boat then

  8. #8
    You Te
    Hey Tom, I don't know if this helps but I can chew gum and walk at the same time.
    You Te

  9. #9
    sorry dog
    I can chew gum and walk at the same time. But can you shoot nitrous and walk at the same time?? I didn't think so.
    Gig - I ain't the expert but I have a 78' 900 and it is 2:1 and my 77' 1500 is the same deal. I've never heard of anyone talk about later inlines (73+) having anything other than 2:1 unless it had speedmaster or a LU from an 85 which is the same cept for having 2.3:1 gears. The 90 you got should not be dist fired like mine but probably has the same little penny sized transfer ports. I've yet to run mine as it is a project that has been shuffled to the bottom of the todo list but people tell me that power falls off after 5000 rpm so it should be Propped for that or just above at WOT.
    [ March 26, 2003, 01:57 PM: Message edited by: sorry dog ]

  10. #10
    gigamurph
    sorry dog:
    I can chew gum and walk at the same time. But can you shoot nitrous and walk at the same time?? I didn't think so.
    Gig - I ain't the expert but I have a 78' 900 and it is 2:1 and my 77' 1500 is the same deal. I've never heard of anyone talk about later inlines (73+) having anything other than 2:1 unless it had speedmaster or a LU from an 85 which is the same cept for having 2.3:1 gears. The 90 you got should not be dist fired like mine but probably has the same little penny sized transfer ports. I've yet to run mine as it is a project that has been shuffled to the bottom of the todo list but people tell me that power falls off after 5000 rpm so it should be Propped for that or just above at WOT. Thanx for the input sd. Seems to be the consensus between you and Tom Brown that it's a 2:1 gear ratio. Just tryin' to do some figurin' and couldn't find the ratio. Could have gone You Te's route but I've gotten friggin' lazy in my old age! Have been runnin' a 19" prop and can only get about 4200rpm. Picked up a 17" last year which should increase the rpm into the recommended WOT range and give me a few more mph (accordin' to thge local mechanic). If I could ever shake this lazy bug, I'd get it changed and find out! Thanx again!
    da gig

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