1986 Johnson 150 GT - Power pack? Cold on one side.

SheldonWare

Recruit
Joined
Apr 6, 2012
Messages
2
Okay, Here it goes.... I am working with a `86 Johnson 150 GT with VRO. We noticed the engine running a tad bit rough, Loss of power/speed, Like it were missing a cylinder or two, and decided to do a few tests. My first assumption is this is an ignition problem because the starboard 3 cylinders are A LOT more cooler than portside cyls. when I run the engine for a few minutes(and I am assuming they are getting little fire) I used a large capacitor and absorbed the spark from each cylinder. When I absorbed the spark from the top port side cylinder coil and the engine started running smooth. I came to the middle starboard coil, and when I absorbed it's spark, The engine RPMS didn't drop, or no fluctuation in sound, or anything else noticable. I have did resistance test in the sensor coil, charge coil, stator, and all that checks out fine. I checked the kill-wire to the power packs, and those are fine. I am not sure what else it could be.

ALso, Keeping in mind that I do not have a DVA Adapter, and can't measure the primary line, or the high tension line on the coils. If I had the correct equipment, there's more I can check, but keep in mind that I do not. I've just been doing all the workarounds I can do. :-/
 

SheldonWare

Recruit
Joined
Apr 6, 2012
Messages
2
Re: 1986 Johnson 150 GT - Power pack? Cold on one side.

Also, The other 4 cyls. that I absorbed the spark from, There was a drop in RPMs like you'd normally see. The capacitor is just like pulling the plug wire off the plug, just a little safer and less stressful on the coilpack.

Okay, Here it goes.... I am working with a `86 Johnson 150 GT with VRO. We noticed the engine running a tad bit rough, Loss of power/speed, Like it were missing a cylinder or two, and decided to do a few tests. My first assumption is this is an ignition problem because the starboard 3 cylinders are A LOT more cooler than portside cyls. when I run the engine for a few minutes(and I am assuming they are getting little fire) I used a large capacitor and absorbed the spark from each cylinder. When I absorbed the spark from the top port side cylinder coil and the engine started running smooth. I came to the middle starboard coil, and when I absorbed it's spark, The engine RPMS didn't drop, or no fluctuation in sound, or anything else noticable. I have did resistance test in the sensor coil, charge coil, stator, and all that checks out fine. I checked the kill-wire to the power packs, and those are fine. I am not sure what else it could be.

ALso, Keeping in mind that I do not have a DVA Adapter, and can't measure the primary line, or the high tension line on the coils. If I had the correct equipment, there's more I can check, but keep in mind that I do not. I've just been doing all the workarounds I can do. :-/
 

emdsapmgr

Supreme Mariner
Joined
Dec 9, 2005
Messages
11,551
Re: 1986 Johnson 150 GT - Power pack? Cold on one side.

You can perform some simple tests on your own. While the engine is running, use some insulated pliers to pull one spark plug lead off one plug. Note if the engine rpm's drop or not. Push that wire back on, and check the next one. Etc. An rpm drop will indicate that the plug is firing properly. (An inductive timing light will also show the quality of spark on each plugwire.) Once you have an idea which plug may be misfiring, you can perform an other simple test: that engine has two identical power packs-each controls the spark to one head. Swap the packs and see if any firing problems on one head-transfer to the other head. If so, you have a bad power pack. You can also swap identical spark plug coils for testing purposes.
 
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