Mercuiser 140 cooling system

[jamesr1]

The temp on my motor is getting to about 185 after running for 30 minutes. Water is circulating though the motor, but I dont think enough water. The hoses on the motor do not feel full or presurized while running. Could this be the impeller that I have heard about? I keep wanting to think getting it in the water will allow a better supply of water to the motor.

 

[rabidfish]

Re: Mercuiser 140 cooling system

If you are runnning it on flush muffs. I would try it in the water first. How long ago was it changed? Shouldn't go more than 3-5 years absolute tops.

 

[jamesr1]

Re: Mercuiser 140 cooling system

It is probably due. I just bought it.

 

[DHPMARINE]

Re: Mercuiser 140 cooling system

Since the boat is new to you,do the water pump job.Then you can diagnos if you have further problems.If you came into my shop tomorrow,that's where we'd have to start.You have to know it's good.<br /><br />DHP

 

[rabidfish]

Re: Mercuiser 140 cooling system

I agree...

 

[fireship1]

Re: Mercuiser 140 cooling system

Hello, Replace the impeller with a full kit. Don't try to save money by just changing the impeller. Pull the exhaust riser and check for clogging. The riser and exhaust manifolds will clog up with rust and will not last forever. Salt water boating will speed up the process. The thermostat will also need to be replaced from time to time. DON'T run the engine without the thermostat. Make sure that it is in place in the housing and replaced with the correct temp stat. This pritty much covers all of the basics of the cooling system. Post back if you need more help.

 

[jamesr1]

Re: Mercuiser 140 cooling system

I did put it in the water this morning, and the temp still got up there, so I will be changing the impeller/thermostat. The boat needs more work than I thought. It seems as though the shift linkage may need adjustment. It was rough in and out of gears. It also falls on its face under a load. I have checked the cylinder presure( changed piston recently ) and think I will rebuild the carb as well. Lots of good advice here on iboats, thanks to all...

 

[Don S]

Re: Mercuiser 140 cooling system

Shift cables don't just "Go Out of Adjustment" when they get old and corroded and worn inside, they bind and need replaced or you have shift problems and the engine will die when you shift out of gear.<br />Boats (especially old boats) always takes more work ($$$$$$) than you think...... that's probably why the previous owner got rid of it.<br />Just like the old saying, the 2 happiest days of a boater life are the day he buys the boat and the day he sells it.

 

[jamesr1]

Re: Mercuiser 140 cooling system

Don,<br /> That being the case I will look at new cables. I have been considering a hot foot accelerator. This would be the time to do it. Are they easy to replace/install?

 

[Don S]

Re: Mercuiser 140 cooling system

The cable I was referring to was the cable from the drive to the engine, not the one to the control.<br /><br /> http://www.mercstuff.com/shiftcable1.htm

 

[jamesr1]

Re: Mercuiser 140 cooling system

Yes, I figured that out. Thanks for the link.

 

[jamesr1]

Re: Mercuiser 140 cooling system

I think this may be due to my thermostat. If I let the motor run for 30-40 minutes it overheats, but after the motor is cool and I remove the drain plug I noticed that the block is full of water. If the block is getting full, then the impeller is delievering the water. right?

 

[Don S]

Re: Mercuiser 140 cooling system

Wrong, it could be filling up with water, but not circulating due to a plugged or partially plugged exhaust riser or manifold or ...... Is your engine raw water cooled or does it have a closed cooling system with a heat exchanger?

 

[jamesr1]

Re: Mercuiser 140 cooling system

Raw water cooled. The hose from the thermostat housing to the water pump does not seemed to get much water flow. If the themostat is sticking or not opening properly wouldn't that limit the amount of water to the water pump,( limiting circulation )?<br /> The thermostat looked like the original, lots of sediment. I have also purchased the impeller rebuild kit and will change that out as well. I had the exhaust and elbow off and did not see any clogged ports. If the block is empty and I hook the muffs up, start the motor, if the block fills with water quickly, wouldn't that indicate the impeller is working? <br /><br /> Don, I am not opposed to tearing the motor down if need be, but I would rather change the impellar and thermostat first. You make me remember and old saying: "Expect the worst, you wont be disappointed." lol