35hp Johnson outboard--problem

[kkahmann]

I gotta a major problem with a '98 Johnson 35 hp--long shaft--tiller. Starts easily--runs fine at all rpm for about 1/2 hour then starts sputtering, missing and dies out after running real rough for a while. Where I live this is just enough time to get into real trouble.

I changed gas tanks and gas lines, I changed plugs--I then replaced the CDI unit and then replaced the 3 coils. Next thing is the stator but they are expensive. Any of you motor heads got any idea's?

[Eric Wettschreck]

Is it running warm? Overheating???

[Cicada]

Ya, make sure it's spitting water out the back. You may need to replace the impeller.

[Outfitter17]

Cicada may be right, It may be as simple as a warn impeler or just pluged intake. Sometimes our motors act like that, when they pull up for shorelunch and pull in some sand or a small pebble.

[kkahmann]

It's not a plugged intake--the indicator water is warm but not hot. I did have to replace the high limit switch a couple of years ago cause I plugged the intake with weeds. When that blew the motor ran fine but would only idle. Saftey thing I guess to keep you from burning up the engine. The rubber impellor looks fine when I take it apart.

Thanks guys

[boatfixer]

How long does it take to restart, or what do you have to do to restart?

[kkahmann]

I have to wait for it to cool off cold to restart--that can take an hour. I'm thinking it is more an overheating problem than a spark problem--lottsa spark when she is cold.

thanks again

[boatfixer]

Are you able to turn it over? or is it locked up?

[kkahmann]

It doesn't lock-up--you can restart it sometimes it just runs really rough--no power and missing.

[boatfixer]

I guess I would check the spark immediately when it happens to start narrowing to either spark, fuel, or compression. Does sound as though it is losing spark on 1 cylinder though.

[Surface Tension]

I'd guess a coil but you replaced them. Next time it happens pull one plug and see if it smooths out. Do that with each cylinder.

[kkahmann]

It turned out to be a bad thermostat. I didn't even know it had a thermostat. Easy fix anyway--thanks guys.