late 1970s model johnson 135hp v4 engine need some help

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chattanoog_josh

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never had a boat, had a jetski last year but this is different to me

so out of water it idles and will go into drive and sputter a little but rev all the way out and spin perfectly

in water itll idle ok, sometimes the N is a little wierd getting into, itll be in N and let you start but the propeller will be engaged
but one in N itll idle fine, then try Drive or Reverse it will bog and eventaully die, it sounds like maybe 100rpm above idle then bog then die
 
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chattanoog_josh

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Re: late 1970s model johnson 135hp v4 engine need some help

pulled plugs, cylinder on left side as looking from rear are wet and one on right has black around and the other looks fairly clean

all 4 plugs are pretty new

going to do compression check in the morning, didnt want to wake the neighbors up tonight
 
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levi_tsk

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Re: late 1970s model johnson 135hp v4 engine need some help

check the compression with all of the plugs out and DO NOT run the engine just roll it over with the starter until the gauge stops rising
 
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chattanoog_josh

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Re: late 1970s model johnson 135hp v4 engine need some help

compression test:

1: 143
2: 145
3: 140
4: 140


so compression seems fine to me
 
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levi_tsk

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Re: late 1970s model johnson 135hp v4 engine need some help

that looks pretty good
have you got an ajustable spark gap tester? check to make sure the spark will jump a 7/16" gap
if you dont have a tester you can get one from your local auto parts place theyre about 5 bux
 
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chattanoog_josh

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Re: late 1970s model johnson 135hp v4 engine need some help

ok ill try and get one of those

so wierd, cleaned a little today fired it up and it idled so perfect, drive and reverse with no sputter max rpm and it was perfect and sounded really good in the driveway, just like brand new

took it out to the lake and it barely idles in the water and as soon as it goes in gear it cuts off.. and when you hit the throttle its like its WAY to rich or WAY to lean like a car carb, it just shuts off when you give it any gas at all

its like night and day from out of water to in water, i cant understand this HUGE difference

ill check the spark gap tester and see how that does
 
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levi_tsk

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Re: late 1970s model johnson 135hp v4 engine need some help

yeah unfortuantely they ALWAYS do that theres no back pressure or load on the engine so the only true test is on the water in gear...
do you have a tach? whats your idle set at on the muffs? needs to be around 1100 out of the water on the muffs

dont rev it out of the water or you can get a "runaway" where the engine over revs and self distructs once it starts all you can do is RUN and hope it doesnt hit you in the back of the head with a piston
 
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chattanoog_josh

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Re: late 1970s model johnson 135hp v4 engine need some help

i dont have a tach, but where is the idle adjuster at on the carb?
 
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levi_tsk

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Re: late 1970s model johnson 135hp v4 engine need some help

its on the lever going to the throttle cable
 
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chattanoog_josh

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Re: late 1970s model johnson 135hp v4 engine need some help

im got a price for like 100$ to look at it, and itll be 2 weeks before they can

ima drop this pos off, its pissin me off

lol
 
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levi_tsk

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Re: late 1970s model johnson 135hp v4 engine need some help

alright man good luck!
 
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