overheating problem with my 4.3 lx mercruiser

[wknd@bernies]

I have twin 4.3 lx engines in my 1989 sundancer. I went out this weekend and the port motor was running about 175 to 180 degrees normally runs 145. First of all impellers were changed in the beginning on the season. I then changed the thermostat with no sucess. pulled the hose off the thermostat housing from outdrive intake and got plenty of water with motor running. Then backflushed oil cooler and nothing was obstructing it, still running hot. Iam now lost and looking for suggestions. Would appreciate your input.
Thanks in advance.


Bill
,

 

[sideways]

Does it get up to 175 at idle or only under load?

How old are your manifolds?

Silly Question... You do have 140 deg thermostats in both motors...

Try swapping themostats between motors if unable to identify..

 

[mperlst216]

My normal is 170.

 

[magstang1]

Sounds like the thermostat was stuck open causing you to run cooler than normal at 145 degrees. Now it's working correctly and getting you to 170-180.

 

[GrandMaster]

Agree with above...4.3's should run 170-180 range

 

[Sangster]

Mine runs 170ish also

Sent from my SM-N900V using Tapatalk

 

[eweise]

Mine also run at 165-170.

 

[wknd@bernies]

Thank for the replies appreciate all the help. I am on Lake Michigan where the water temp. Is only about 67 to 70 degrees. I put in a 140 temp thermostat, and a new intake water hose on the out drive , new sender unit replaced the nylon balls in the thermostat housing. I noticed that when I start the engine when cold the temperature gauge seems to rise quite fast on that motor. I purchased a laser temperature gauge and after taking the boat out on the lake the gauge goes to 180 or so but the laser reads 128-130 on the thermostat housing but got a reading of 200-210 on the risers when running on plane. But running at the dock the risers stay about 128-130 degrees. Any suggestions would be greatly appreciated.

Thank you,
Bill