Mercruiser Cooling Question

[rhrose]

I have a 99 Wellcraft with Mercruiser 5.0. This past Sat went out skiing with some friends. On the trip in I heard a brief noise, but boat kept running fine. The next morning, my girlfriend and I went out early to take advantage of the calm water. After about 15 min of iding and 30 - 40 min of skiing, I shut the engine down to pick her up and it wouldn't start back. Went to diagnose the problem and realized the serpentine belt had been thrown off. I immediately turned the key back on and the temp gauge only showed about 160-170. Between her pulling me and me watching her, I don't ever remember paying attention to the temp and I know she didn't look at at. I figure we had run approx 45 min - hour without serpentine belt and was really worried about the water pump cooling the engine, probably spent 5 min off before I checked temp at about 160-170. Would there be enough flow somehow to keep engine cool? I got towed in, got new belt, ran boat for about 15 min and seemed to be fine as usual. Does the engine get water flow by other than the water pump? Do you think I have hurt anything? Thanks.

 

[Haut Medoc]

Re: Mercruiser Cooling Question

Welcome to iboats.......
The raw water impeller should have kept enough water pushing through to prevent damage......
If you have not suffered any loss of performance, I would say you are OK.....
Ya might want to keep an eye on the oil & pull the spark plugs after a few hours & inspect their condition.....
A 'steamed clean' plug would indicate a blown head gasket.....​

 

[Don S]

Re: Mercruiser Cooling Question

On a raw water cooled engine the raw water pump can keep it cool. Partially. It may not circulate the water around the back of the engine as well as the circ pump but it will keep it cool.
The 99 engine SHOULD have an overtemp alarm.

 

[achris]

Re: Mercruiser Cooling Question

First off, I assume you had an obsever in the boat while you and her were skiing... Bit silly (and very illegal) if you didn't...

There is a water pump in the stern drive leg (I am assuming it's a stern drive) that will have kept water up to the engine.. If it's in good condition you may have got lucky (very lucky). In theory it could supply enough water to keep the engine from overheating. There is also an audible alarm system that would have sounded if the engine did overheat. you do check each morning that you use the boat that the alarm is working, don,t you? The alarm system monitors engine oil pressure, engine temperature and stern drive unit oil level. It should sound when you go to start the engine because there is no oil pressure at that point. I know you didn't check your oil level and give the engine a visual check that morning because you would have found the belt to be off from the day before....

If the alarm is working and it didn't sounds on overheat, then you have probably dogded the bullet.... Lucky you.... You may remember to do your daily checks in future....

Chris...........

 

[rhrose]

Re: Mercruiser Cooling Question

Thanks for your reponses.

Your right - no visual that morning - I did previous day when putting in, but none that morning.

Alarm - I've only had boat few months and never noticed an alarm. I'm familiar with outboard alarms that sound before starting, but this one doesn't do that. Should this one have a similar one? Any other way to check.

We were skiing without an observer that morning, which is why I don't feel that I was paying much attention to the gauges. However, had been pulled over for that before, but was informed that it was legal with the use of a wide angle viewing mirror.

Again thanks for the replies.

Rob

 

[Haut Medoc]

Re: Mercruiser Cooling Question

Thanks for your reponses.

Your right - no visual that morning - I did previous day when putting in, but none that morning.

Alarm - I've only had boat few months and never noticed an alarm. I'm familiar with outboard alarms that sound before starting, but this one doesn't do that. Should this one have a similar one? Any other way to check.

We were skiing without an observer that morning, which is why I don't feel that I was paying much attention to the gauges. However, had been pulled over for that before, but was informed that it was legal with the use of a wide angle viewing mirror.

Again thanks for the replies.

Rob

What state is that?.......

 

[rhrose]

Re: Mercruiser Cooling Question

KY

It is illegal for a vessel to tow a person(s) on water-skis, a surfboard, or any other device unless:
A person at least 12 years old, in addition to the vessel operator, is on board observing the towed person(s) or ...
The vessel has a wide-angle (160 degree field of vision) rearview mirror mounted such that the operator can observe the towed person(s) at all times

 

[Dakota47]

Re: Mercruiser Cooling Question

yep, same law in Wyoming, (no observer needed) just a rear view mirror.

 

[Haut Medoc]

Re: Mercruiser Cooling Question

Wow!.....​

 

[Ranger2050]

Re: Mercruiser Cooling Question

Same in Tennessee, too.

 

[88wellcraft]

Re: Mercruiser Cooling Question

Time to move Haut?

 

[Haut Medoc]

Re: Mercruiser Cooling Question

Time to move Haut?

Move, nah!....
Though in my younger years I did ski on the Hudson River at night under the Newburgh Bridge after having a few at Gully's, with just me & another person driving.....
I can see the wisdom of having a third party observing.....
However, I do like the freedom to be able to choose.....
Kinda like nanny seat belt laws.....​