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Johnson 9.5hp sportwin stuttering problems

alekap

New member
Hello everyone, i'm new here. I've got and 1972 johnson evinrude sportwin 9.5hp
When i got it it was having a hard time starting and it was stuttering like in the video below (keep in mind this isn't my engine in the video, i will post a video of mine as soon as i record it). So first i thought it was an ignition problem so i changed the ignition coils since they were cracked, cleaned the points set the gap to 0.020" changed the cables a put in new plugs. I also pulled off the carburetor cleaned it, and blown it out, i didn't rebuild it since it's not that easy for me to get parts since i'm not from the states, and nothing has changed. The engine still starts hard and stutters, and wont stay running at low rpm, at high rpm it runs a little bit better, also the also the idle adjustment knob does nothing. So i'm stuck now and any help would be really appreciated. I really want to get this engine running since i was planning to restore it completely, but i want to get it running smoothly first.

video i mentioned: https://www.youtube.com/watch?v=VL3v3zqqPo0
 
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The high speed jet ( AKA orifice ) is in the bottom of the float bowl.----Did you take it out for cleaning , yes or no ?----All the fuel goes through the high speed jet.----The low speed jet doing nothing would point to a blockage in the carburetor.----Or the sneeze is caused by throttle plate opening too soon.
 
Does removing the cover help??? These motors are known to develop under the cover exhaust leaks which can affect running performance.
 
Hi again, and thanks for all the replies.

First off i did the compression test today it's around 60psi on both cylinders, also i get a blue spark that jumps around 1/5 of an inch.
Last time i tried cleaning it i didn't take the high speed jet off located on the bottom of the float bowl. Why would the throttle plate open too soon and how would i adjust it properly? If it is the carburetor is there a way to clean it at least partially to get any results other than rebuilding it since i can't get a hold of the rebuild kit at the moment?
Also i run it without the cover for all the testing.
 
???----If the arm above the carburetor and the follower on the cam is not adjusted properly the carburetor will be open too soon !!----For proper idle the throttle plate must be closed.-----Cleaning the carburetor normally does not require the kit.---And that high speed orifice must be clean.---Even fuel for idle goes through it.
 
okay i will clean the high speed jet, and try to adjust the throttle plate. But how would i go about cleaning the low speed circuit, any suggestions?
 
Your next step now is to find the adjusting screw for the throttle cam follower .---It is item # 40 on this site for the carburetor parts.-----Find the mark on the throttle cam.---Throttle should just start tom OPEN when mark on the cam touches the follower.-----Test run the motor.
 
Hi again.

You were totally right about the throttle plate it was half way open on idle, and it should be totally closed, i have adjusted it, i'm gonna clean the carb one more time tomorrow and try it out. Fingers crossed ;)
It was a nice call, i would have never remembered to check that. Thanks!:D
I'll report back as soon as i test run it with the results.
 
You may need to do a bit of adjusting on the low speed needle now.-----Obviously it has had idle issues for a while and who knows what was attempted to correct it.
 
I have tried it out today and it runs like a dream. I still have to take it out on the water i'll post the results of that as soon as i try it out. Finally some good news. Tank you so much.
Also i have another one it think its 68 9.5 its the white one. I'll try to get that one runninh aswell since i want ti restore both of them. So i'll post back here if i run into any trouble with it.
 
Sorry,-----They were white in 64 / 65 with cowling release knob on the cover for those 2 years and 66 was the last year for an all white 9.5 hp motor.
 
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yeah it's the one with the cowling release knob on the cover. so its 65/64 then. :D Anyway while we are on the topic. im missing that knob on that engine, does someone has a closeup picture of it so i can maybe remake it since i doubt i will be able to find and buy it.
 
huh, could you give me a link, because i was looking for it and couldn't find it. I'm still not so good at navigating this website. :D
--->Edit: Never mind i found it. Thanks!

Anyway now i have been thinking about it, the reason i thought it was 68, is because the link for the slow speed needle on the carb is flexible like on my 72 sportwin. and i know those things started at around 68, before they were solid rods. So someone must have changed the the whole slow adjust assembly or the whole carb.
 
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So i have tried it out on water today, and i have a new issue. The engine runs great revs up great. But it just wont push the boat it's like the proppeler isnt turning as fast as thr engine or is "slipping" for some reason. Do you guys have any idea what could it be? Thanks
 
Many folks do not know how to identify the year of motors of that era !!!------Try another prop as the rubber hub may be slipping !
 
I have checked the prop it' good and the prop isn't slipping, but i can turn the flywheel with my hands while in gear while holding the shaft at the bottom whit almost no resistance. Does that mean the lu is bad?
 
Okay, so i took the lu apart and it turns out it is in pristine condition, so i took another look at the prop and you were right it was the rubber part slipping inside the prop.
so i took it out, here is the picIMG_20180318_193121-min (1)-min.jpg

So my question is: Is that thing supposed to slip inside the prop, just not that much, or is it not supposed to slip at all?
 
I will try another prop, because i luckily have another one, but is there anything i can do to this one so it doesn't slip so much?
 
Hi Guys,

I am having exactly the same problem as alekap, the only difference is my throttle plate is closed. I have cleaned the carb twice, honed the cylinders, replaced the head gasket, adjusted the points and adjusted fuel air mixture screw. There is lots of spark, compression is 70 psi in both cylinders and yet it will sputter and stall when I roll back on the throttle to idle position. Runs great at faster rpms. I checked the reed valves and they look fine. I'm not sure what else it could be. Any suggestions would be greatly appreciated.
 
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