'71 50hp johnson timing and carbs

T

todster

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I have a elctro-hyd shift large gearbox johnson 1971 50hp.
Am trying to set throttle ,idle mix and timing. What is correct procedure? right now at idle timing is at about 2 deg after atdc. not sure on max as still want rest right before that. Throttle set to line and butterfly just starting to move. the link to cam is adjustable-- what should length be? ie... should idle be at the line on cam with roller lined up or will roller not be touching. Manual doesn't state such just says line up at marks so butterfly is just moving but doesn't say if this is idle position.
Thanks
 
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todster

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Re: '71 50hp johnson timing and carbs

I have max timing set at 19 deg btc. to maintain idle it falls right at the alignment mark for throttle /cam or just slightly past. should idle be just timing then as advance throttle, plates start to open or are plates slightly opened at idle?
 
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todster

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Re: '71 50hp johnson timing and carbs

Was looking at plug chart link posted in forum and see that boatsetup.com says motor takes l77jc4 plugs at .030 and motor has l78v S.G. plugs and cowl decal calls for l77v S.G. Does a 1980 cowl fit the 71's or is chart wrong. And from experience would the plugs make a difference at idle. It runs great once of idle circuit. Rebuild kits (carb, Sierra) from napa will be here tomorrow as well as plugs indicated on cowl. Any takes on the plugs?
 
larky

larky

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Re: '71 50hp johnson timing and carbs

todster
i have the same motor and would like to know the same things your asking. my responce will bump the thread to the top of the list again.
what manual do you have? it doesnt sound like it explains things well and I would like to avoid buying the manual that you have if its not informative enough.
as for the plugs, L77JC4 is what i have read on other posts to be the correct plug with a gap of .030, and QL77JC4 at the same gap for less electrical interference (recalling the electrical interference part from memory so i could be wrong).
good luck with your motor
 
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todster

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Re: '71 50hp johnson timing and carbs

I bought a manual on ebay~ original johnson for $25. Haven't received it yet though. Creek_side_manuals is the seller. I also found a torrent with the seloc manual and downloaded the pdf.
 
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todster

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Re: '71 50hp johnson timing and carbs

Larky, my motor has l78v plugs in it. Just put rebuilt carbs back on it and new plugs that champion book says go in it ql77... I'll send you these plugs if you want (only have less than 2 minutes on them), I'm sticking with the surface gap plugs like cowl says it takes. About 4 turns more on screw to make it idle with the ql plugs at .030. The champion book is wrong, I think.
 
larky

larky

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Re: '71 50hp johnson timing and carbs

thanks for the offer on the plugs but i have napa a few minutes down the road that always has them, but thanks anyway, a very kind offer. I was looking at my outboard and was wondering how the relationship between the throttle cam and the timer base should be set, because my idle adjustment has to be screwed almost all the way in to obtain the correct idle rpms

tonight i'm putting the old girl back together after replacing the powerhead to exhaust adapter gasket, because of a leak that would fill the engine cowl and choke out the engine. can't wait to see how she pushes my boat, just bought the motor a few weeks ago:)
 
T

todster

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Re: '71 50hp johnson timing and carbs

I finally bought a set of carbs on ebay for $20 after shipping. Must have been something amiss with the others in the idle passages. This baby idles beautiful now.
 
tashasdaddy

tashasdaddy

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Re: '71 50hp johnson timing and carbs

took you a while. glad to hear it's working.
 
Benny1963

Benny1963

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Re: '71 50hp johnson timing and carbs

hey whats up people .just checking out your post,
had the 72 50 johnson hydro elec shift.
it was a good motor recently sold it .i did the carbs powerpack waterpump on it then .if i remember correctly .it took some tuneing .but once i had it tuned it ran and started well.there good motors ,there are some post on here for the carbs .adjustments,theres a good carb building sticky on here .also try to get factory manual.i gave mine to the guy that bought the motor.
i have some electronics. powerpack / couple of coils /timer base and stator
starter ,maybe a set of controls /if yall need something.
bennyb
 
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