1970 9.5 hp spark problems

Evinrude Boater

Evinrude Boater

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Recently purchased this engine after having saw it run. It was difficult to start and didn't run again after it stalled. I cleaned the fuel system since this engine has been in storage for a few years. Using light-up spark testers I verified last night that there was spark but tonight there's nothing. Used an adjustable gap spark tester as well. Are there any safety switches that might prevent it from starting such as a neutral safety? I unplugged the kill switch wires. Should there be continuity between those two wires when the switch is disconnected or is that normal?
It's getting fresh fuel, it's in the test barrel water.
Spark plugs cleaned and gapped
Compression is about 60 psi
 
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Beek14

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Re: 1970 9.5 hp spark problems

Well if you checked the spark with a tester and it shows nothing, pull the flywheel and check the plate. Probably could use a tune up kit. It's possible points could have burned or become worn just from that last run. That compression is pretty low... Even with good spark, that's only going to move so well with 60 psi, plus idle might be rough if it runs at all...
 
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Rick.

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Re: 1970 9.5 hp spark problems

The stop button is normally open so yes there would be continuity between the wires to the engine, not the switch. No other safety switches. I would not be alarmed about the compression. Hopefully it might improve with some use or a decarb. They are a low compression engine. Weird that you would have spark one night and not the next. I agree with above you need to pull the flywheel and check under there. Best of luck. Rick.
 
Evinrude Boater

Evinrude Boater

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Re: 1970 9.5 hp spark problems

Points look old and tired and the coils are original and cracked. One has an arc burn hole through the bottom into the armature plate. Sounds like a good place to start.
 
iwombat

iwombat

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Re: 1970 9.5 hp spark problems

60 psi is a fine reading for any rope-start motor and that one in particular. The important thing is that they're even.

Those 70s (and previous) coils were never built to last into the 90s and beyond. I've yet to see a good set.
 
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Rick.

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Re: 1970 9.5 hp spark problems

New coils, points, condensers and plug wires would be a wise start. A new impeller also if it's more than a couple of years old. Even a different gauge will probably yield different compression numbers. Points gap is .020 and they need to be very clean. Rick.
 
Evinrude Boater

Evinrude Boater

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Re: 1970 9.5 hp spark problems

iwombat said:
Those 70s (and previous) coils were never built to last into the 90s and beyond. I've yet to see a good set.
Click to expand...

They're not like the coil in my 1964 Speedifour which is still going to this day.
 
Evinrude Boater

Evinrude Boater

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Re: 1970 9.5 hp spark problems

New coils, points and condensors and it started and ran when testing for spark. I didn't even have the fuel line on it yet.
 
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Rick.

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Re: 1970 9.5 hp spark problems

Now that's the kind of news we all like to hear. Imagine what it will do when it's hooked up to a fuel line! LOL. Rick.
 
Evinrude Boater

Evinrude Boater

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Re: 1970 9.5 hp spark problems

When I had the magnito plate out the throttle linkage was disturbed and the engagement with the gear on the tiller handle shaft was changed. Can anyone describe how to re-engage it properly with the rack and link? I was just turning the handle until it extended all the way then engaged it and turned it back in.
 
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