Cool down after a run?

[Lauralex]

Someone mentioned to me that after a hop I should let the engines in my boat idle for a few minutes to "cool down." Usually once I get in we attach the lines and I cut both engines, so they are idling but only for about a minute or two. When they reach operating temp they are usually both at a little under 170 degrees according to the dash gauges. I let them idle for about 5 minutes today and the temp stayed the same. They have never run hot yet.

Should I let them idle for a few minutes longer? If so, what about when I am anchoring? Once anchored I normally just cut them and thus far everything has been fine. These motors have 460 hours on them and run flawlessly in my book. I just want to make sure I am doing everything correctly to keep them that way as long as possible. These are 350 MAGS MPFI in case that matters.

Thanks.

Brian.

 

[JV II]

Not a bad idea, but I doubt you are going from cruise RPM or WOT to tying up or anchoring within a minute or two. Idling to the dock or scoping out your anchorage counts.

 

[Our Serenity]

If you are slipped or moored in a marina, don't you have to travel a bit in a no-wake zone before you get to your spot? We have a 3 or 4 minute travel down a no-wake channel before we get to our slip in our marina.

 

[Loneranger]

I may be wrong but once the engines get to operating temperature (which will occur just at idle) then they stay at operating temperature until they are not operating. I do not see where a cool down period would make much sense from a temperature standpoint. I have never practiced this.

John

 

[Lauralex]

If you are slipped or moored in a marina, don't you have to travel a bit in a no-wake zone before you get to your spot? We have a 3 or 4 minute travel down a no-wake channel before we get to our slip in our marina.

Yes we have a breakwater on our marina that I have to go around at idle to get past, then to the slip, then putting it in the slip, so it's idling for at least 4-5 minutes each way. Also when do find a place to anchor we are puttering at idle for a good 7-10 minutes dodging other boats, etc. Guess I'm already doing it.

 

[ShamuToo]

I may be wrong but once the engines get to operating temperature (which will occur just at idle) then they stay at operating temperature until they are not operating. I do not see where a cool down period would make much sense from a temperature standpoint. I have never practiced this.

John

Exactly! That's what the thermostats are for.

 

[Lazy Daze]

I may be wrong but once the engines get to operating temperature (which will occur just at idle) then they stay at operating temperature until they are not operating. I do not see where a cool down period would make much sense from a temperature standpoint. I have never practiced this.

John

Your line of thinking is correct. But, when the engine is running hard, things do heat up. The temperature at the gauge sender may read the same, but other parts can get hotter. I think the important thing is just give it a few minutes - but, as mentioned above, rarely do you go from full out to full stop.

Now, on an engine with a turbocharger, it is more important to let it cool down since that turbo can get way over 1,000* and when the engine stops, the oil supply to the turbo stops as well.

 

[sbw1]

Now, on an engine with a turbocharger, it is more important to let it cool down since that turbo can get way over 1,000* and when the engine stops, the oil supply to the turbo stops as well.

It's important to let the oil cool down before shutting down an engine with a turbocharger. The life of the oil is shortened if the engine is shut down hot.

 

[Loneranger]

What would it cost to put a turbocharger on your boat?
On a car it runs $5000 or better. Hmm.. not that I want a turbocharger or anything; I guess I would just get a go fast boat if I did.

John

 

[PMC]

What would it cost to put a turbocharger on your boat?
On a car it runs $5000 or better. Hmm.. not that I want a turbocharger or anything; I guess I would just get a go fast boat if I did.

John

hmmmm - skip the turbo (heat problems and all:grin go with blower instead. I think this would fit?:smt043

just being a troll today :lol:

 

[midway]

The 4.3L carbed engines have to idle or they will diesel when you shut them down, there are hot spots that need to cool before you shut down, most of the time you have accomplished this with the docking, no wake time.