www.iFourWinns.com

Hello,
I'm still new and learning with boats. I have the above OB on my 180 F&S. Last weekend out on the lake it started acting up. At speed the temp would drop rapidly and the engine alarm would sound. Once dropped back to idle the to would rise and alarm would stop. Does anyone have any idea what would cause this? I an thinking there may be an impeller issue. I don't know the last time it was changed I bough the boat this year. Other than that it is in great shape and runs smooth. If it is the impeller how do I change it?

Or temp sensor. (Most likely in my opinion) if so, where can I get one and where is it on the engine? I'm good with cars so it will be an easy change for me.

for the impeller change: youtube "outboard water pump" or something of the like and there is some nice fella who walks you through changing the water pump. you'll only be doing the impeller, but the process should be the same.

I would say your temp sender is grounding out or losing it's ground while your at speed (moving more) check those wires to see if there's anything up.

Thanks for the info. By chance can you point me in the direction of where it is on the motor? Is it the lone wire going into the brass sensor on the port side of the motor?

Sorry, but I'm new to boat motors.

Sounds to me like an electrical problem, not a water pump since the temp drops. You have 2 temperature switches, one on each head, on yours I think they are between the top 2 cylinders on each side. Id check for a broken or bare wire to start with.

_________________
Brian Borchik
The Winds of Cold Springs Harbor Marina
Baldwinsville, NY

^^ This

you can't quite see the senders as there is a black cover holding them on. Facing from the outside of the boat, the right side should have one wire coming out, left side has 2. The black covers come of pretty easy, and only go back in a 1/4 turn past hand tight.

My temp gauge isn't working now, so i'm trouble shooting as well. Be sure to post up if you find anything.

Ever figure out the issue? I pulled my sensors and both looked good. The only issue was a wire pinched woen the line. I removed the crimp did a back flush, and hit the lake. Ran like a champ all day pulling a tube. the coolest it went was @ 130 at WOT, but surface temps were also @ 60 deg.

i'm still without a temp gauge. i'm begining to think it's the actual gauge itself or the connectors too it. My senders look good (though not really sure what a bad one would look like), and all the wires are tight.

No offense to the guys here (as they are awesome!) but if you have quesions with the outboard you may want to find your way over to http://www.thehulltruth.com and http://forums.iboats.com/forumdisplay.php?f=24 for all your Johnson OB questions.

Glad you're up and running!