Need help with 1968 1.5 HP Johnson model SC-10S

[racerone]

Looks normal to me.

 

[Crosbyman]

great.... I guess some are just more pointy or blunt see pict.

what about the plugs do they look wet or dry when it dies ?
inlet needle doing the job ? bulb get hard ??

 

[racerone]

There is only 1 cylinder.----There is no primer bulb on this motor !

 

[Crosbyman]

There is only 1 cylinder.----There is no primer bulb on this motor !

dang... morning cobwebs :-(

Andrei... sell it !

 

[racerone]

Some simple trouble shooting should be done.----Run with timing light to determine if it is a---" loss of spark issue"----- or a fuel issue !!

 

[andreipou]

How do I do timing light on this motor?
It is so primitive , it has no design for that.

 

[racerone]

Trouble shooting means ---" gathering the facts " ---about the motor.-----The approach of " the neighbor says this " or " it must be this " ----Or making assumptions does not work.

 

[racerone]

You are saying it can't be done ???-----Wait wait.----Get the battery from your riding lawn mower.----Hook up the timing light.-----Observe the flashing of the light .----And you can find the timing mark on the magneto plate as well.-----Should fire between those 2 vertical lines all the time.-----These things are elegantly simple.----Sorry if it sounds like a broken record to you.

 

[andreipou]

dang... morning cobwebs :-(

Andrei... sell it !

My wife says that I am old stubborn nutcase...
I am not a mechanic , but I was able to revive motors that are "spaceships" comparing to this motor that is simple like a rock.
I will not be in peace with myself if I give up now...

 

[Plankwalker]

I have noticed over-revving on my older 2hp when I turned the high speed needle in a bit too far. Double check all timing issues; point gap, when the speed handle engages the butterfly valve (at SLOW, it should just touch the arm), and your spark plug gap. I found that the only way to properly adjust the slow speed needle was out on the water. Once the engine is warmed up and running at high speed, I turned it in until the engine stalled. That would be my LEAN setting. Half a turn out would be my RICH setting.

 

[racerone]

You set the HIGH speed mixture at full throttle.-----Then slow the motor to idle for setting the low speed mixture.

 

[andreipou]

You are saying it can't be done ???-----Wait wait.----Get the battery from your riding lawn mower.----Hook up the timing light.-----Observe the flashing of the light .----And you can find the timing mark on the magneto plate as well.-----Should fire between those 2 vertical lines all the time.-----These things are elegantly simple.----Sorry if it sounds like a broken record to you.

This motor does not have timing marks. Also, original service manual for this model does not mention them either.

 

[racerone]

It does have timing marks.----You are stubborn and don't want to look for them -----On the magplate and one notch on the flywheel !

 

[Crosbyman]

poke a shiskabob stick in the cyl and find the high spot of the cyl. => TDC

measure the points with a ohmeter and confirm the points just open at TDC . turn the fw and set the points at .020

recheck that points open at TDC with the stick ... you will feel the high point of the cyl.

that should help you going... you can fine tune later

btw your coil does measure 4-7Kohms with ground ?

 

[racerone]

I think I see the 2 timing marks on the magplate in the middle picture.-----Hint, the timing narks do not look like what you find on a 57 chevy like grandpa had.

 

[andreipou]

You are right , I got my glasses on and found 3 tiny bumps.
But, the little guy strikes back.
After another disassembly\assembly it does not start anymore. Not even sneeze.
It means one thing: I am doing something wrong.
I know that the best solution for this is to stop, take a step back and think.
This is what I will do for now and spend some time getting ready for bear season opening on Saturday.
Meanwhile, one thought - I always try to order original OMC parts , but for this motor dealer did not have points , only aftermarket. So, I got points and coil and condenser aftermarket.
Now, I found original points on Ebay (NOS) and ordered OMC coil and condenser. Just to be sure.
I will get back to this motor after I get them.
Will keep you posted...

 

[Plankwalker]

I have noticed over-revving on my older 2hp when I turned the high speed needle in a bit too far. Double check all timing issues; point gap, when the speed handle engages the butterfly valve (at SLOW, it should just touch the arm), and your spark plug gap. I found that the only way to properly adjust the slow speed needle was out on the water. Once the engine is warmed up and running at high speed, I turned it in until the engine stalled. That would be my LEAN setting. Half a turn out would be my RICH setting.

Darn it, I meant the high speed needle. Shoot.

 

[andreipou]

I am back to this little guy.
Got new OMC coil, points and condenser.
Put them in and got strong spark on 1/4'' gap tester.
Disassembled and cleaned carb one more time.
Motor starts and runs fine about 600 rpms with timing mark right in the middle of 2 bars. So, aftermarket ignition parts did add to the issue(s).
I can increase speed about up to 1/3 turn (pic 1) from START to FAST position (pic 2) . It runs fine.
If I turn further it stalls.
I unplugged fuel line from tank valve and connected 6 gallons external tank raised it high thinking that maybe it is not enough fuel flow pressure from internal tank, but it it did not help.
Paying with needles does not help. The most stable run is at recommended 1/2 HS turn and 1&1/4 LS turn.

What else can I try?

 

[Crosbyman]

compression # = ???

1.5hp so it does not burn rubber but isn't just for trolling ?

will it speed up if you spray fuel in the carb face ? yes .. then it is a fuel issue or low vacum in the crankcase . jmho

 

[racerone]

Perhaps test / replace magneto ground wire.