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1978 85Hp Johnson is hard to start cold, easy when hot.

Yes, use a screwdriver with handle of wood or plastic so you won't feel the shock.
I think you can see the key from above once the nut is removed. There may be a washer under the nut too. Some crankshafts are not mortised out for the key all the way to the top, where you can see if it's lined up with the flywheel mortise. In this case, of course, you will have to get your hands on a flywheel puller and then check the key. Pullers can be borrowed or rented from your parts retailers.
 
Hi no not yet as I don’t know which carb throat goes to which cylinder. Hopefully there’s a diagram in the workshop manual.
 
Re the screwdriver inserted in the plug socket I assume the spark must be jumping from the side of the screwdriver shaft. Thanks I’ll try that, spark off the plugs is white spark at either end but a gold colour between.
 
I’ll get new plugs over the weekend as my local auto stores are out of stock of the recommended champion plugs but will be near a further store this weekend.
 
You can check your flywheel indexing by removing plugs, inserting a pencil in each cylinder and rotate the flywheel by hand until piston is at top dead center. Timing pointer should point to that cylinders number on flywheel.
 
Ok thanks is the flywheel indexing to test if the flywheel key has sheared and timing is out? I tested the plugs again this evening using the screwdriver method and I’m not getting strong snapping blue spark as described on other threads. Leads 1-2-4 will jump a 7/16 gap but spark is thin and a gold colour. Lead no 3 is weaker and doesn’t jump the 7/16.
 
New plugs had to be ordered online they’re on their way.

Could a dud battery or starter cable continue to cause the motor to run badly once it is running? I assumed that once running the motor creates its own current for ignition.
 
Last edited:
Louie,

Yes, the pencil test is described in the factory manual as a quick test to ensure the flywheel is indexed properly. If the key gets damaged or sheared the flywheel can move on the tapered shaft.
 
Hi I tried the flywheel index test but the only cylinder that has a mark on the flywheel is no1 which lines up with a TDC mark on the flywheel, there are no marks for the other cylinders when they hit TDC. There are marks to the left of the TDC marker from 4-36 in increments of 4. I tried to upload a photo of that but didn’t work. Can I post photos from the quick reply box?
 
Squirting fuel into the top carb throat did not seem to make much change to the running, squirting into the bottom throat caused a loud cough and motor stalled.
 
I think I may have found the problem, the center of the fuel pump outer seal is missing around the small central shaft, this I think has lead to excess fuel getting into the cylinders and also running out the bottom of the air box. The plugs were constantly very wet with fuel when I checked them today after reving it and dropping back to idle. Fuel pump diaphragm looks thin and a bit perished so I’ve ordered a new Sierra pump. Will report back when it goes on with new plugs.
 
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