Heated my Johnny 115 yesterday

[Cricket Too]

Please don't yell at me, haha, I had this in the non-repair forum, but this forum gets a lot more traffic, so I figured I'd try for some more opinions/answers here. Thanks.

I ran through some weeds yesterday with my 1997 Johnson 115 and didn't realize they were blocking my water intake screens on my LU, so when I opened it up to get on plane, my overheat alarm went off about 30 seconds later and my Hot light came on.

I instantly slowed down and shut it off, lifted the motor out and saw all the weeds, cleaned them all off, but the LU was really hot. I put it back in the water and let it sit for about 5 minutes, and then started it again and let it idle to get some water moving through it. The light and alarm were still on for about another minute while idling and then both went off.

I let it idle for another 5 minutes or so and then went on my way, and it ran perfect for the rest of the day.

So I guess my question is, could I have done any damage, or does the overheat alarm come on before you get hot enough to do any real damage?

Also what temp does it usually come on at?


Thanks.

 

[tashasdaddy]

Re: Heated my Johnny 115 yesterday

i answered your other post.

 

[Cricket Too]

Re: Heated my Johnny 115 yesterday

Hey TD, yeah I saw that, I just figured I'd throw it over here, since it seems there are way more eyes over on this forum.

I just put a new water pump in it about 3 weeks ago, and it's still spitting hard and far out of the exhaust pressure relief holes in neutral, so I'm pretty sure my impeller is still good. It was so quick that I doubt I did any damage, and I got it running and cooled off in about 5 minutes anyway, just figured I'd see what people say.

I have never overheated an engine before, so I wasn't sure if the warning comes on before any damage occurs, or if you should be concerned anytime you heat one.

Thanks.

 

[iwombat]

Re: Heated my Johnny 115 yesterday

At the very least, you want to retorque your head bolts. If any are real loose, you'll need to inspect the head for warping and replace the gasket.

 

[Cricket Too]

Re: Heated my Johnny 115 yesterday

Does the overheat alarm generally come on before you reach a high enough temp to do any real damage?

Somebody else mentioned it comes on at 240 degrees, now that's about 100 degrees higher than the engine is supposed to run, so it seems to me that's too high to be a warning, and at that point it could already be too hot, in which case the alarm makes no sense to me.

From the time the alarm went off to when I shut it down was about 10-20 seconds, I pulled the throttle back and shut the key down right away. Then it sat for about 5 minutes until I started it back up.

 

[slimdaddy45]

Re: Heated my Johnny 115 yesterday

Does the overheat alarm generally come on before you reach a high enough temp to do any real damage?

Somebody else mentioned it comes on at 240 degrees, now that's about 100 degrees higher than the engine is supposed to run, so it seems to me that's too high to be a warning, and at that point it could already be too hot, in which case the alarm makes no sense to me.

From the time the alarm went off to when I shut it down was about 10-20 seconds, I pulled the throttle back and shut the key down right away. Then it sat for about 5 minutes until I started it back up.

I talk to a boat shop today about a problem he told me that the alarm goes off at 180 on a 85 hp probaly yours is the same

 

[iwombat]

Re: Heated my Johnny 115 yesterday

They do come on right at the hairy edge of when damage can occur. If you shut it off right then and there you'll probably end up with minimal issues.