www.iFourWinns.com

Hi

I have a 2003 Four Winns 268. I recently had a problem with the engine running hot, I shut it down and got a tow back to dry land.

I replaced the water pump and thermostat and backed the boat into the water and ran the engine with the boat on the trailer. Temp went up to 175 and maintained for 30 minutes. I launched and at idle within a minute of starting to motor the temperature went past 175 to 190, and I shut it down again and was towed back to dry land.

At the dock I removed the thermostat and was able to start the motor and limp onto the the trailer. The temperature did start to go down.

I removed the risers, they look pretty bad, but I can blow through the water line and the sir seems to be flowing ok. Not that I have anything to compare it with.

My next step is replacing the risers, if that fails, what else can I do to identify the problem.

When running in land with a hose connected to the outdrive, the engine also runs steady and 175.

I'd appreciate any assistance.

Thank you,

that is about all you can do is start replacing parts and that is what a marina shop will do at an ungodly price. my boat is overheating but intermettently.

are you salt water then my guess are the maniflods and risers on your boat.

my boat is fresh water and probably does not need risers, my raw water pumps was replaced 60 hrs ago and the thermostat was the same time. leaving the sensors and circulating pump, which is where i am heading.
you mentionded water pump but which s it, raw water or circulating?
hope this helps

Sounds like it could be manifolds and riser but a couple more things to note. When you replaced your impeller, were there any missing pieces? If so you might have some stuck down stream restricting flow.
Also, make sure the pickup on your outdrive is clear of anything.

_________________
--2002 3880 Regal Flybridge | Twin Merc 8.1HO **Seven**
--2003 AB 13 VST Console Inflatable | Tohatsu 40hp TLDI **Phish'n ski**
--310 Mercury Inflatable | 1982 9.9 Johnson

Ok the first thing to understand is that with a raw water cooling system, it removes heat from the engine by low pressure high volume water flow. So unlike a closed system, the engine has to have a high volume of cool water in and warmer water out. Anything that reduces the volume of flow can cause overheating. This includes:
worn impellers
Clogged raw water intakes on the outdrive (especially for boats moored or docked in brackish or salt water where marine growth is a problem). I had this issue on my Cobra and had to spilt the upper and lower gear housings to clean out the water intakes. There was a plastic screen in there that had growth on it even if I painted it with anti fouling paint so I removed the screen about 6 years ago and no more overheating.
clogged water ports in your manifolds and elbows, this keeps water from exiting the engine and will cause overheating. In salt water they have to be replaced every 5-7 years, depending on the salinity of the water.
sticking thermostats, if they do not open all the way. However, I have had more problems with thermostats that don't close all the way (running too cool) than sticking closed (running too hot).

If your elbows looked bad you probably need to replace them and the manifolds may need to be replaced as well.

Fresh water or salt?

_________________
88 Four Winns 200 Horizon
4.3 OMC Cobra-4bbl
2002 Walker Bay 10/2012 Suzuki 2.5
2008 Walker Bay 8

1998 Jeep Grand Cherokee 4.0/Selectrac
2007 Jeep Grand Cherokee 5.7 Hemi/Quadradrive II