175 Johnson runs great...for 10 minutes!!

apsjls

Cadet
Joined
Oct 2, 2009
Messages
6
Boat is a 93 Stratos with a 175 Johnson Faststrike. Trip to the lake 3 weeks ago had us walking the dog for 10-12 minutes (all the way to the other side of the lake) - then it just died. Will restart immediately with no problems, but you give it throttle and it dies. Idled all the way back. Took the boat out of the water - put it back in 2 hours later to test it again - did the exact same thing - ran great for 10-12 minutes then died. Did this a 3rd time with the exact same results. I just put an impeller in it and took it to the lake yesterday to test. Ran great for 15 minutes (again - bonehead took it all the way across the lake) and it died. Idled back for 2.5 hours...good stuff.

What's wrong with it???

My shadetree (non-outboard) engine experience tells me it's something electrical - potentially overheating - any guesses???

Thanks in advance.
 

Joe Reeves

Supreme Mariner
Joined
Feb 24, 2002
Messages
13,262
Re: 175 Johnson runs great...for 10 minutes!!

Does your warning horn beep (self test) when you first turn the key to the ON position?

Do you receive any warning horn signals?
 

apsjls

Cadet
Joined
Oct 2, 2009
Messages
6
Re: 175 Johnson runs great...for 10 minutes!!

No audibles at all. Not 100% sure they are hooked up.?

I installed 2 jumper wires today between the rectifier and stator to test voltage on the stator - @ idle, it was between 16-18 Volts. As throttle increases, voltage increases all the way up to 50. Does anyone know if this is normal? Should it go all the way up to 50 volts? Also - if normal, does this rule out the stator?

Thanks
 

apsjls

Cadet
Joined
Oct 2, 2009
Messages
6
Re: 175 Johnson runs great...for 10 minutes!!

Now that I think about it - there is one audible when the key is initially turned to on position. But that's it.
 

blue_streak

Cadet
Joined
Aug 22, 2008
Messages
14
Re: 175 Johnson runs great...for 10 minutes!!

others on here have suggested if it dies suddenly, it's electrical. if it dies gradually, it's fuel related. what ya got for us to work with?
 

mikesea

Lieutenant Commander
Joined
Oct 1, 2006
Messages
1,830
Re: 175 Johnson runs great...for 10 minutes!!

Try running with your fuel cap loosened,you may have a venting problem,does the squeeze ball get sucked and collapse,if you squeeze it as the problem happens ,will it get better,have you tried choking as it begins to shut down.The fact it lets you idle ,leads me to fuel
 

apsjls

Cadet
Joined
Oct 2, 2009
Messages
6
Re: 175 Johnson runs great...for 10 minutes!!

I initially thought fuel also, but the fuel bulb doesn't loose pressure, like it's a fuel problem. Plus after I took it out of the water the first time, then put it back in a couple of hours later, it ran perfect for 10-12 minutes again. I would think if it was fuel related, after it messed up the first time, it would stay messed up.??

I would call it dying suddenly - it's not a gradual shutdown - it's immediate.

With all the people I've talked to - 8 of 9 mechanics who would actually talk to me said it was electrical. The one that didn't thought it might be the impeller - since the old man has had the boat for several years now and hasn't put an impeller in it, I went ahead and did it.

Is there a way to test the powerpack?

Also - a could be critical note - the rectifier has gotten sooo hot at some point in the past, that the wax has boiled up and splattered. None of the mechanics say that the rectifier would be causing this type of issue though.
 

jonesg

Admiral
Joined
Feb 22, 2008
Messages
7,174
Re: 175 Johnson runs great...for 10 minutes!!

Its an optical ignition,
when it dies disconnect the rectifier and see if spark returns, if it does replace the rectifier.
Engines can run without a rectifier but a bad rectifier can shut the ignition down.
 

apsjls

Cadet
Joined
Oct 2, 2009
Messages
6
Re: 175 Johnson runs great...for 10 minutes!!

OK - So I am on the fence about buying coils and powerpack...somebody push me over the edge.

Has any ever replaced coils only? Would it benefit me to only change coils first? If it's in fact the powerpack, and I change the coils, can I damage the new coils?

It's only money right? haha - I guess if it was simple, they wouldn't call it a problem.

Thanks to all the replies so far - regardless of dollars spent, I'll post what the end fix was...even if I'm cussing when I type it. :)
 

apsjls

Cadet
Joined
Oct 2, 2009
Messages
6
The Solution

The Solution

Installed new CDI coils this week and took the boat to the lake today for a test run. It ran like a scalded dog! I ran it for 30-35 minutes and it ran great the whole time!

New impeller kit - $45
New coils - $100
Boat fixed - PRICELESS

Thanks for everybody's input!
 
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