70 Johnson 9.5 points?

U

ugmold

Petty Officer 2nd Class
Joined
Jun 2, 2008
Messages
132
Hi folks,
Last year my 1970 Johnson 9.5 which has been trouble free for 6 years or so started feeling like it was mis-firing when I pulled started it, slight kickback.
So this year I figured I better check the points. I took off the flywheel, set the point cam at the little arrow lined up to where the point arm contacts and found the points to be adjusted way smaller than the .020 spec. I did not measure this but proceeded to run an emory/sandpaper then a dollar bill to clean off any residue and set them at .020. I have spark, but no power. Took a bunch of pulls, where last year 1 or 2 usually did it and it ran good.

Yes the points/condensers are old. But I do have a good spark.
 
R

racerone

Supreme Mariner
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Dec 28, 2013
Messages
38,426
Real spark on these jumps a gap of 1/4" or more.----How dooes your ignition perform on that test.-----Compression test needs to be done.
 
C

Crosbyman

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Messages
5,651
could be just dirty carb now....

unscrew the bottom front bolt on the carb and the LS needle give it a shot of carb cleaner to clear any crud build up and reinstall. if it does not work service the crab

see Leroys... these 9.5 must be 100 % clean to run good
This carburetor must be absolutely, positively, SQUEAKY CLEAN. And it is very easily clogged, so may need to be checked often if there is a possibility of dirty fuel.

Leeroy's Ramblngs is coming soon

We are doing some maintenance on our site. Please come back later.
www.leeroysramblings.com www.leeroysramblings.com
 
U

ugmold

Petty Officer 2nd Class
Joined
Jun 2, 2008
Messages
132
racerone said:
Real spark on these jumps a gap of 1/4" or more.----How dooes your ignition perform on that test.-----Compression test needs to be done.
Click to expand...
Looks like only the bottom cylinder can achieve that kind of spark. I assume that would be the mag/points towards the back of the motor.
 
U

ugmold

Petty Officer 2nd Class
Joined
Jun 2, 2008
Messages
132
Crosbyman said:
could be just dirty carb now....

unscrew the bottom front bolt on the carb and the LS needle give it a shot of carb cleaner to clear any crud build up and reinstall. if it does not work service the crab

see Leroys... these 9.5 must be 100 % clean to run good
This carburetor must be absolutely, positively, SQUEAKY CLEAN. And it is very easily clogged, so may need to be checked often if there is a possibility of dirty fuel.

Leeroy's Ramblngs is coming soon

We are doing some maintenance on our site. Please come back later.
www.leeroysramblings.com www.leeroysramblings.com
Click to expand...
I always drain it at the end of the season and run a bit of marvel mystery oil in it, but indeed I will clean the LS needle.
 
U

ugmold

Petty Officer 2nd Class
Joined
Jun 2, 2008
Messages
132
racerone said:
Real spark on these jumps a gap of 1/4" or more.----How dooes your ignition perform on that test.-----Compression test needs to be done.
Click to expand...
Compression around 62 each, I know that is low, but have heard not for 9.5
 
C

Crosbyman

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Joined
Nov 5, 2006
Messages
5,651
according to Leroy'S these 9.5 are low comp. engine.

if it works don't fix it

I never had much over 70 on half a dozen 9.5s !

Leroy's ...
Compression : Compression on these motors may seem lower than some of the others. Displacement of the these 9.5 hp motors is 15.2 Cubic Inches with a Wide Open Throttle of 4500 RPMs. Where the later 9.9/15 HP motors utilized 13.2 CI at 5000/6000 RPM, where higher RPM increases the HP. A normal compression reading of 65# to 75# appears to be fine for this motor.
 
U

ugmold

Petty Officer 2nd Class
Joined
Jun 2, 2008
Messages
132
Crosbyman said:
according to Leroy'S these 9.5 are low comp. engine.

if it works don't fix it

I never had much over 70 on half a dozen 9.5s !

Leroy's ...
Compression : Compression on these motors may seem lower than some of the others. Displacement of the these 9.5 hp motors is 15.2 Cubic Inches with a Wide Open Throttle of 4500 RPMs. Where the later 9.9/15 HP motors utilized 13.2 CI at 5000/6000 RPM, where higher RPM increases the HP. A normal compression reading of 65# to 75# appears to be fine for this motor.
Click to expand...
Who is this Leroy guy? Website?
 
G

ghostgixxer

Cadet
Joined
Jun 24, 2020
Messages
13
ugmold said:
Hi folks,
Last year my 1970 Johnson 9.5 which has been trouble free for 6 years or so started feeling like it was mis-firing when I pulled started it, slight kickback.
So this year I figured I better check the points. I took off the flywheel, set the point cam at the little arrow lined up to where the point arm contacts and found the points to be adjusted way smaller than the .020 spec. I did not measure this but proceeded to run an emory/sandpaper then a dollar bill to clean off any residue and set them at .020. I have spark, but no power. Took a bunch of pulls, where last year 1 or 2 usually did it and it ran good.

Yes the points/condensers are old. But I do have a good spark.
Click to expand...
Points gap is very important, but what you’re describing @ kickback might be bad timing, look at points set position first... most systems uses the same principles, they must be set @ top of timing cam lobe when piston(s) is top dead center (TDC) . Kickback will mostly happens when one of the points is off timing, the other one(s) setted right will make the engine firing up when you crank pull it but the bad one will mostly pre ignite and stop/reverse the rotation cycle (kickback) , start with that !! If everything’s right then remove your carbs , inspect intake gaskets or intake boots depending on your engine, if ok then open up the carbs and look for clogged jets/obstructed circuits, also inspect your reed valves for proper sealing/seating or damages (broken or cracked) , but usually when you have major kickback issues it’s related to timing! Keep us updated !!

Chris
 
oldboat1

oldboat1

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9,612
similar kickback with a lawnmower a couple of years ago -- turned out to be a sheared flywheel key, throwing off the timing. New key, and it fired up perfectly.
 
R

racerone

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Dec 28, 2013
Messages
38,426
A sheared flywheel key on a breaker point / magneto engine means that there will be no spark.
 
oldboat1

oldboat1

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(unlike my old lawnmower, I guess.) The key broke off and jammed the flywheel. My Dad used to talk about kickback when hand cranking a model - T. I was getting something like that.
 
U

ugmold

Petty Officer 2nd Class
Joined
Jun 2, 2008
Messages
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This morning I decided to take the suspicious points out and have a better look. OMG, worst looking points I have ever seen. One side is a deep pit and the other a size DD. picts don't do them justice.
 

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C

Crosbyman

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the job of the condenser is to protect the points from arcing to much...!

time for new condensers ! and points :)
 
U

ugmold

Petty Officer 2nd Class
Joined
Jun 2, 2008
Messages
132
You're right Crosbyman. I filled down the bump and pitted sides and tried it out. Ran great! But new points/condensers are most certainly in need and on order.
Thanks for the support, good motivator.
 
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