Johnson 6hp quit....why?

99cyclone

Cadet
Joined
May 9, 2009
Messages
7
I got a new (to me) 1987 6hp Johnson to push my 14' aluminum fishing boat around.

This morning was its first trip on the lake. The motor started and ran beautifully, so I set out across the water. Got out to the middle (about 10-15 minutes in) and it quit.

The engine would re-start, but would not run above idle. I pulled the cover off and checked connections, all looked good. Started babying it back to the dock, having to re-start it every 30 seconds to 1 minute.

Got about half way back to shore, and it started running like normal again! So...I put the cover back on and motored around the dock area for 10 minutes or so with no more signs of trouble.

Has anyone experienced this before? It seems to be running good now (knock on wood), but I don't want to get stranded the next time out.

Any insight is much appreciated.
 

Alex1342

Cadet
Joined
May 7, 2009
Messages
18
Re: Johnson 6hp quit....why?

If it wasn't running above idle, it may have been your carb. You said this motor is new to you? Perhaps the previous owner had the motor stored without properly preparing it for storage. You just may have fixed the issue just by puttin' around cleared and burned off all that set in gunk in your carbs. Wouldn't hurt though to just take apart the carb and give it nice clean and rebuild.
 

99cyclone

Cadet
Joined
May 9, 2009
Messages
7
Re: Johnson 6hp quit....why?

The previous owner was using the motor pretty regularly, and had it on the water at least once already this season.

The gas is without a doubt from last season. I'll run some fresh gas through and keep an eye on it.

Just want to be sure this isn't a sign of some impending failure.
 

Alex1342

Cadet
Joined
May 7, 2009
Messages
18
Re: Johnson 6hp quit....why?

That is most likely at fault. The bad gas.
Gas from last season would cause that.
If there was a significant time of non-usage between the time the previous owner ran the motor and to the time of passing it off to you, bad fuel would foul up those carbs real quick. And i'm assuming he didn't run the motor dry.
Rebuild your carbs and and run fresh fuel through the system. You should be good to go.
 

Vic.S

Rear Admiral
Joined
May 4, 2004
Messages
4,690
Re: Johnson 6hp quit....why?

Just like to add that when your 6hp was new in 1987 the instructions may have been to run on 100:1 mix. That is wrong and it should be run on 50:1

Currently recommended plugs are QL77JC4 gapped at 0.030" . That may have changed from the original as well.

Agree bad fuel or dirt or water in carb could be the trouble.

Check tank is venting properly too.
 
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