Low Power Question - Johnson 60hp

[mhenchen44]

I've inherited a 15 footer with a 1983 Johnson 60hp outboard. It starts up and idles great but has very little power on the water. I've replaced the impeller for good measure and just recently cleaned and rebuilt the carbs (per a previous suggestion from this board). When I tested it out on the water the same thing happened. As the engine was running, I pulled the top plug wire and the engine kept running the same way. Replaced the top and pulled the bottom wire and I got zapped and the boat quit instantly.
The top plug wire does have a bit of wear and abrasion marks on the elbow connecting to the plug.
I'm thinking about taking the engine into the shop, because the shop mechanic told me that I'd have to purchase special tools in order to diagnose the problem correctly.
Is this correct? Also does anybody know if I can switch the top wire for the bottom one to see if the wire is bad? Is there another way I can test the wire (continuity on a regular tester perhaps?)
Finally, and most importantly, does anybody know some simple tests I might do to diagnose my problem without having to go to the shop.
Any help would be appreciated. Thanks in advance!

p.s. after realizing the problem, I headed back to shore. On my way in, at near full throttle, the engine started to pick up power slowly on its own. Thought this may help with diagnosis.

 

[tashasdaddy]

Re: Low Power Question - Johnson 60hp

ok you need to do a couple of things, like start with the basics, there was no difference in the running of the motor when the top plug wire was pulled. thus saying it's not running on the top plug. you can completely swap positions with the coils, including the position, and connections in the power pack. draw a diagram where the wires go. screw that up and more problems. move bottom coil to top cylinder, and top to bottom.. now when you pull the plug wire, if the top stops the motor you know that coil is good, if there is no difference when you pull the bottom plug wire. replace the bottom coil. this lets you know if the coil is the problem, or the powerpack. if it says the same and the top makes no difference, and the bottom stops the motor, then we check for poor compression or no fuel getting to top cylinder. totally confused?

 

[mhenchen44]

Re: Low Power Question - Johnson 60hp

Initially confused, but I think I got it. Thanks so much.

One other question though. Is there an easy way to tell if its my powerpack or my coil that is the problem (assuming it's an ignition issue)?

Thanks again.

 

[HighTrim]

Re: Low Power Question - Johnson 60hp

First of all, have you checked spark? Lide TD's said, start with the basics of spark and compression. A cheap spark tester can be bought for about 10 bucks or you can even make one out of a board and nails, search this forum for ideas. Your spark should jump 7/16 of an inch with a strong blue ZAP! To determine accurately the condition of components of the ignition system, an ignition tester should be used. Without the use of test equipment, coils may be replaced needlessly. A wide variety of ignition testers are available from various manufacturers. If you do make sure you remove the coil from the power head and perform all tests on a wooden or insulated bench top to prevent leakage or shock hazards. If you can get a hold of a tester, i can tell you the steps. Visually look at the coils for cracks? To check the diode in the power pack use an ohmmeter set to high ohms scale. Disconnect the leads from Power Pack terminals and connect the ohmmeter leads between, noting reading. Reverse the ohmmeter leads and note reading. An infinite or very high reading in both directions indicates the diode is open. A low ohms reading in both directions (approx 100 ohms) indicates a shorted diode. A normal diode will read resistance in one direction and infinite reading in the other direction. If the diode is defective, replace power pack.

Check compression and spark first though. If you get a strong and steady firing one coil at a time on all cylinders across a 7/16 spark gap, i think your ignition system is ok, but others on here may have better advice.

 

[Dennisanoka]

Re: Low Power Question - Johnson 60hp

If you move the spark plug wire and the problem follows it, it's the wire. If you move the coil and the problem follows it, it's the coil. If the problem doesn't move we need to move on to other possiblities. Try those two first.

 

[johnmodic]

Re: Low Power Question - Johnson 60hp

I just signed up. How did you input your question?

 

[HighTrim]

Re: Low Power Question - Johnson 60hp

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