Boat Engine Overheating

I own a 1999 Sea Ray I/O 18'. The steering got tight so I took it to local boat shop. My son and I put the boat in the water after the repair and it immediately started smoking when running. The smoking got worse and the engine overheated and locked up. A rubber coupling that looks like it is part of a water cooling intake caught fire, melted and water began pouring into the boat. What could the mechanic have done to cause this problem? Thanks

Man I hate to hear about that. I totally understand what you're saying.

Here's a few things that cause overheat:
1. water pump failure due to lack of regular maintenance.
2. water pump failure due to running the engine without supplying water to the lower unit (there's not a marine tech in the world that would ever do that to a customer's boat -- any who did would be out of business already, it's just one of the cardinal rules).
3. friction caused by inadequate oiling due to broke-down oil pump or forgetting to add oil to the gasoline or to the oil reservoir.
4. lean mixure due to lack of carburetor maintenance.

I'm sure there's a few more, that's all I can think of right off-hand.

But what causes the damage you described is the failure to shut the engine off at the first sound of the overtemp alarm. Or the first sighting of smoke.

To get some satisfaction from your mechanic (unless he just owns up to forgetting some crucial bit of wrenching that I don't know about), you'll probably need some science -- it's highly likely that a good qualified marine tech with expertise in your particular brand of motor/outdrive combo will be able to pinpoint a cause of death. Highly recommend you prepare yourself for the conclusion that it's unrelated to the recent shop visit.

Good luck.

2009-04-22 18:38:28 by SoccerSammie

MUSTAD MARINE: Oct. 2009 - During a yacht delivery between San Francisco and San Diego one of the two Cummins Diesels overheats on a 50-footer ...

I changed head gaskets, both water pumps, and thermostat. The hoses look ok and are not leaking. The belts are tight and no slipping that i can see. It is getting plenty of water flow to the engine. I removed a plug on the side of the water pump to check! all fluid levels are full.
the thermostat was removed and water jacket was cleaned very good and rinsed out when the gasket were changed.
this a fresh water cooled engine. i am getting plenty of flow, and exhaust water is coming out ok. maybe this will help??????????
it was overheating before the gaskets were changed. agian the thermostat was removed and still overheating!!!!!!!!!!!
my dad said that a high output water pump may help?????????

Sounds like a possible thermostat issue! Take it out and test it. Make sure it opens as you heat a pan of water with the thermostat submerged. Even a new one can be faulty!

2006-06-26 02:46:06 by rhimes2220

Price: $19.99 $19.99

NPT standard threads
Essential to protect engines from overheating
Solid brass

Boats are not like cars, where traction is close to absolute. Just wondering, if I was towing an ocean liner with a 5HP boat, would my engine overheat at all, or would it simply keep churning out water at the end and we wouldn't really go anywhere anytime soon?

No question, you can put an overload on your engine. The propeller (propulsion train) is designed for a nominal load. Ever notice how people do not drive their boats at "full throttle" all the time.

PS what you do is "heat" the water with your screw. The turbulence is where the energy goes. So when I tie you to the ocean liner and ask you to swim, you will tire quickly and not move an inch.

PPS and then there was "action equals reaction". The force which you exert on the ocean liner does not do much to accelerate its giant mass visibly (and this also against the friction of the water)

2007-05-21 14:57:12 by Chaco-Yekke Downyonder

Price: $400.00 $358.95

Automatic thermostat turns heater on at 40°F and off at 52°F
350 Cubic Feet
Dimensions: 8'' x 4'' x 5-1/8''

The chevy 305 engine on my boat is overheating. I suspect it is the head gasket. Here are the compression results on each cylinder:

1 = 115
2 = 130
3 = 146
4 = 135
5 = 146
6 = 149
7 = 146
8 = 150

There is also a lot of what looks like steam coming from the crank case.

My other thought is that it is a bad water pump.

My thought is I would do a cylinder leakdown of that #1 Cly. I would pull the heads and look for a failed gasket, cracked calender wall, cracked head. To perform a CLT you will need to bring the engine
up to TDC apply compressed air, 50-100 psi should do it. and observe
where the compression is going. If you have a bad water pump you would not have any flow out of you lower unit. IB or OB? you never said. The impeller in the lower unit is pumping isn't it? If it is allowed to run dry it will burn up in minutes.

2008-08-22 17:28:43 by hardyz fan

i have a 1982 searay sundancer. i just had a new engine installed new water pump new pump in the outdrive. the manifold and risers are about 2 years old. the engine overheats in the water and with earmuffs. with the boat in a boat slip i puller the water hose near the transoms and the outdrive is pushing water through it. I took the thermostat out and it still overheats. the gauge is fine. Is there a diagram that shows the water flow? so i can check the water flow.

Ive had alot of experience with that particilar motor and had a strage problem with one side overheating, problem was that one of the manifolds had a leak in the water jacket. Check your manifolds and risers. Theyve got the flow diagrams in mercruiser manuals, goto a dealer and see if theyll let you see one.

2009-07-08 17:00:55 by tony45power