Tell it to me straight

[rdwsdw1]

I have a 1990 Johnson 150 (TJ150SLESB) motor that was having some problems that I thought was fuel related. The motor would run fine sometimes (WOT around 5K RPM's) but sometimes it would not go above 4K and refuse to go on plane. I replaced all fuel lines including primer bulb, rebuilt carbs, replaced the VRO with a fuel pump (VRO had a crack in the housing) and the problem didnt go away but didnt get worse either. Tuesday I did a compression test (all were between 89 and 91), a link/sync, and a spark test on all cylindars. The spark was red in color on the tester but I don't know if that was normal or not.

Wed morning the wife and I go to the lake and I try to start the motor. It was a bit hard to start and idled rough but this had been normal lately. Got about a half mile to a mile out and the motor quit and was smoking. I pulled the cover off and the voltage regulator was white hot and starting to catch fire. Long story short we got towed back to the dock, the fire didnt spread much stayed mostly around the voltage regulator.

What I am looking for is could the voltage regulator have been causing the stalling problem, and how bad could this be? I am figuring at the least I have to replace the voltage regulator, stator, wiring harness, and power pack. Anything I might have missed? How difficult could replacing these parts be? I have a seloc manual but if I attempt this myself Ill definitely be looking for the manufacturers service manual.

 

[jonesg]

Re: Tell it to me straight

OK so the regulator is kinda shot ,

but what about that spark test you did, is it a spark GAP tester?
Go to auto store and buy a cheap adjustable gap tester for around $10.

Spark should jump 7/16th inch gap and be a blue snap, you might as well go ahead and replace the burnt part for now and make sure you use a gap tester.

I wouldn't run the boat until this is sorted out, the stator will be next if its not already melted.

You should get the factory service book written for your engine,

www.outboardbooks.com

 

[rdwsdw1]

Re: Tell it to me straight

I should probably be a little more clear about the fire. It didnt smother when the cowl was put back on, it got worse and even melted the top of the cowl so I am figuring the stator along with the wiring harness and obviously the voltage regulator are toast. I wont know for sure until I pull the flywheel and test it but if the fire got hot enough to melt the cowl....... As far as I can tell it stayed just in that area though.

 

[jonesg]

Re: Tell it to me straight

Molded resin does burn quite well, I've seen that before, sometimes the only thing left is the glass fiber.
oh well, investigate, look at the power pack too.

 

[ezeke]

Re: Tell it to me straight

Regulated rectifiers sometimes burn when the wiring in the potting fuses. It may or may not damage other components, but the stator is the ignition component that usually goes first if the battery voltage reaches the ignition due to the fused wiring in the rectifier.

At any rate, if you have not done so, map the rectifier wiring and cut all of the rectifier wires until you can replace it. The engine can run without the rectifier.

In addition to all of the normal reasons for the regulated rectifier to go bad like loose battery cables, not getting enough cooling water will also do it.