2005 280 T4.3L MPI starboard runs 10 degrees hotter the port.

T

threejays

Member
Aug 16, 2014
81
Macomb
Boat Info
2000 310 Searay Sundancer
Engines
Twin 7.4 MPI's
I need some advice from the Experts J I’m in the process of buying a 2005 280 Searay Sundance with 227 hours on it. The mechanic that takes care of the maintenance told me that the starboard side engine runs hotter (10 degree’s ) then the portside, He told me this is normal because of the hot water tank being in line. Does this sound right?



Thanks,

Jonathan
 
Hope your getting it surveyed.
The surveyor can read the engines ECM with a scan tool to verify operating temperature of both motors.
That doesn't sound right to me. It's taking the water that already went thru the engine to cool it to the hot water heater to heat the cold water in the heat exchanger.
Unless there's a restriction preventing the water from exiting fast enough (heat exchanger in water heater clogged or a restriction in a line)
That would raise a flag to me.
 
Yes I'm having a survey done along with a sea trial. I question it too and I think the easiest why to prove it is disconnect the hot water tank and see if the temp comes down. I knew the impellers haven't been replaced since the seller has owned the boat, I think it would run real hot if that was failing. I'm going to call mercruiser and see what they say?
 
Salt or fresh water? If manifolds and risers haven't been done and it's in salt water then they are due and the parts alone are very expensive. Also def replace the impellers. That's easy to do
 
let the surveyor do his inspection and write his report.
It's up to the seller if he is going to repair the problems that arise or take money off the selling price.
Pay the extra money and have oil samples taken on both engines after the sea trial.
 
threejays said:
Yes I'm having a survey done along with a sea trial. I question it too and I think the easiest why to prove it is disconnect the hot water tank and see if the temp comes down. I knew the impellers haven't been replaced since the seller has owned the boat, I think it would run real hot if that was failing. I'm going to call mercruiser and see what they say?
Click to expand...

That is a lot of hours and time on one set of impellers. I'd be surprised if they aren't severely compromised and that could be your answer. What other service was done?
 
It’s a fresh water boat and not in the water yet. All this information is coming from the marine mechanic who has performed the maintenance on this boat for last three years. He is telling me the port temp is 170 and starboard side 180, once it hits that temp doesn’t move up any higher ( per the mechanic ) . The seller has agreed to replace the bellows and impellers since none of it has been done to his knowledge. I guess the best thing to do is let the engine surveyor tell me what he thinks?
 
Good idea. What is the psi for water pressure in the smartcraft gauges? I'm sure impellers will make a difference but those temps seem high with a 160 t-stat.
 
I have that exact boat and motor set up. Your mechanic is blowing smoke up your skirt. It's NOT running hot because of the HW heater. Now it could if there is a restriction in the loop but not because it's in line. Something else is up, maybe bad manifolds.risers, maybe an inline restriction, impeller needs changed or a bad thermostat. I'd find a new mechanic.

BTW, both of my motors run at the exact same temps.
 
Agree w/ all of the above.

My dash gauges differ by 10 degrees. However, when I hit the engines with an IR thermometer, they are within a degree of each other inspection point for inspection point.
 
Thanks for the feed back!! I talked to the seller and the mechanic again today,both are telling me that the 180 temp on the starboard side has been like this for three years, One other thing they mention was the oil pressure is higher then port side to. The mechanic has flushed the cooling system and also check for hot spots using a IR laser temper gun and found nothing. I'm having a different Surveyor look at both engines. I also called MerCruiser and ask for their opinion? They told me there could be a temp and oil pressure difference from one engine to another but they also suggest replacing the impeller, check the thermostat,temp sensor and the smart gauge it self. I also know there's an exhaust flapper that can fail and cause temper problems. This really sucks this boat only has 227 hours on it ugh..
 
You could try swapping the temp sensors to see if they are reading correctly. My 280 ran at 160 on both sides. How much is the oil psi off by?
 
I was thinking the same thing swap the sensor and see if it changes, The oil pressure is 5 psi higher than port side.
 
My oil pressures are 54 and 56 at 3200 rpm's. Seems like temps and pressures can be a few degrees or psi off but we at around 160 and your at 180. That's a big jump. Def try the sensor switching and a laser temp gun where the sensor is. My stingray cause was off. Always read higher when slowing but laser gun always showed 165 always.
 
Just to echo what others have said. Both my engines run at 160-63 and are almost always in sync. I have a hot water heater. Caveat for me is that I am fresh water cooled.
 
04/16 is the survey I'll check everything you guys mentioned. Thanks for the feed back!!!
 
Take an IR temperature sensor and measure the temperature on both engines right at the temperature sensors. Hold the IR temp semsor at the same distance and same angle in both cases.
The other thing to check is that the ground connection to the bad engine is good, both at the main connection to the block, there are probably 2 and that all the connections in the main connector are good. The oil pressure and temp sensors are just variable resistors to gnd so any additional resistance in the sensor path will affect the readings.
 
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