Topic: 1969 Evinrude / 1971 Johnson 9.5 Runs Poor – Antique Outboard Motor Club,Inc

This topic has 21 replies, 6 voices, and was last updated 1 year, 6 months ago by Buccaneer.

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May 27, 2023 at 9:42 pm #276504
Buccaneer
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US Member
First time I had this one on the boat. Went thru carb, ignition, etc. It’s a 69 Evinrude powerhead in a 71 Johnson.
Sometimes it runs great wide open, other times it won’t quite wind out. Runs rough at slow speeds. “Shaky”
and somewhat noisy, even though I checked out all the rubber motor mounts and added the vibration dampers
to each side of the powerhead. The “carb to mag” syncing procedure in the manual didn’t work out with the marks
I found, but it started on first pull. I removed the hood while running just in case it was choking on it’s own exhaust
but that didn’t seem to make a difference. Back to the drawing board?
Any ideas? First one of these I’ve ever worked on.

https://youtu.be/LxuKI9zggXQ

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May 28, 2023 at 12:34 am #276511
jeff-register
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US Member - 2 Years
Maybe top crank seal blowing fuel on the magneto?
May 28, 2023 at 5:58 am #276516
billw
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US Member
How’s the side-to-side play between the mag plate and the crank case? I’m also having a weeping fuel pump diaphragm come up in my noggin…?

Long live American manufacturing!
May 28, 2023 at 9:32 am #276518
Buccaneer
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US Member
Thanks for the ideas gentlemen. When I originally took the
flywheel off, it had no appearance of every being “oily”.

The fuel pump diaphragms are original, so there could be
some issues, but it seem to be getting plenty fuel.
I haven’t explored if there’s a pump kit available for these yet.

I don’t remember there being any excess play in the mag plate,
but that’s something to explore.

So far I’ve put a new impeller in it. I was going to see if the motor
was viable before I dumped more money into a motor I’ll probably
never use. I do like to try to solve mysteries though, so I may
go back to the basics. I’m not even sure if I put new condensers
in it when I had it apart.

One thing that bugged me, I never was able to sync the mag to carb per instructions
in the manual. The assumed mark I found never lined up with the throttle roller,
or something to that effect.

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May 28, 2023 at 9:52 pm #276542
fleetwin
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US Member - 2 Years
Well, I think the sync might be your issue. There are a few different linkage pieces here that are easy to mix up and not get installed properly. I wish I could be more explicit in my guess, but I remember having this same issue that last time I looked at one of these issues many years ago. The key here is that you can’t get the sync to line up according to manual instructions. If those linkage pieces are not assembled correctly, the throttle plate will be held open and the engine will sneeze/pop at low speeds. And yes, I did hear the somewhat rich condition at high speeds, but let’s try to get the sync right which might solve that issue as well.
May 28, 2023 at 10:20 pm #276543
Buccaneer
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US Member
Thanks Fleetwin, I will concentrate on the sync when I get back to it.
Perhaps some of the 71 and 69 parts got mixed, and aren’t
playing well together?

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June 2, 2023 at 7:56 am #276676
crosbyman
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Canada Member - 2 Years
i believe a square fuel pump will directly replace the current one for a test ..anyway

have you done a total carb job as per Leroy’s intruction incl. ? the LS circuit (see UTUBEs on part 1&2 for the 9.5)

have you seen the UTBE where the owner shows that using the link/synk notch on the cam wasn’t exactly the right spot ?

old plug wires not arcing or open in a bend around the mag plate ????

kill wires not frayed and grounding ??

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June 2, 2023 at 9:00 am #276678
Buccaneer
Participant
US Member
Crosbyman, Thanks for the input!

Regarding the fuel pump, are you talking about an OMC pump,
B&S, or ?

I have not watched the Leroy YouTube video on the carb, nor
can I remember much about the carb when I worked on the motor,
but I seem to remember it seemed very clean inside.

I’ll have to revisit several things you mentioned! Thanks.

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June 2, 2023 at 9:24 am #276679
Buccaneer
Participant
US Member
Looked at Youtube for 1/2 hour, and did not find any “Leroy” carb and sync videos.
Tons of videos on cleaning the 9.5 hp carbs, but did not find one on syncing.

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June 2, 2023 at 11:24 am #276687
crosbyman
Participant
Canada Member - 2 Years
Leeroy’Sis just an article on the MQ version not utube… sorry for any confusion part1-2 alluded to specific videos see below

the link sync process is posted above I did see a video about a guy who said the “notch position” was not the perfect place for the cam follower . he adjusted a bit more to the right side of it—>

try the conventional way…. adjust cam follower to just start to open the plate at START when the cam touches it….

small square pump omc ……… fits perfect over the pulse hole if I recall

9.5 Hp Johnson Evinrude Outboard Carburetor Rebuild – 1of2 – YouTube

(125) 9.5 Hp Johnson Evinrude Outboard Carburetor Rebuild – 2of2 – YouTube

Johnson (leeroysramblings.com)

….. There is no aftermarket carburetor kit available for these motors. The BRP part # is 0382048, which includes the float. Available for $30.96 as of 5-2013. I am disappointed in this kit. It comes with, (like most) repair parts for both the early and late carbs but does not come with everything. On this carburetor, there is a 1/2″ core plug on the outer part of the carb that is inline with 3 small holes in the carb throat. These holes had to be drilled through the access hole this core plug covers up. However INSIDE and under the core plug is a plastic filler plug #0312909 that is not included. On the one I repaired, it would be impossible to remove this plastic plug without destroying it. Oh yes, this kit also included a old style fuel pump cover gasket and filter screen.

adjust the side knob … for good idle speed

goind off line for a good while… good luck

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