Merc 4.3 cooling ?

[wood45s]

Merc 4.3 cooling ?
I bought it with new/rebuilt engine ? has not been in water. It's a 1995 model.
Running on water hose connected to engine waterpump inlet at low rpm, after it?s warmed up the starboard hose to the riser gets pretty warm, but the port side hose only gets a little warm. Is this normal or a problem?
It has the 6 hose thermostat housing with the spacer installed as shown in the factory Merc manual.
Is there a certain way that spacer should face? I think I have the opening in the spacer to the rear now.

The stern drive is currently not on it ? taken off for water pump/ gimbal brg, etc.
After first cranking of cold engine, as it warms up the temp guage moves to the mid position. Then it goes down a bunch as the thermostat opens. I?m used to seeing this initial warming and the thermostat open in a car, but goes up higher in this boat engine than I usually see in my small block chev pickup.
I put new dryjoint exhaust manifolds on it.
Thermostat is currently a new 160 that I checked on stove with thermometer.

thx,
wood

 

[Scott Danforth]

first, you do not have a complete system assembled and you are on the trailer, running on idle. if one manifold is slightly higher than the other because your trailer is leaning a bit, one manifold will be so much warmer than the other.....this is normal because water finds it level

yes, there is a certain way the spacer should face. there is also a notch in the housing and a tab on the spacer. the opening in the spacer must face the openings in the housing.

your boat and your truck are two different animals. you are trying to compare a potato to a pineapple. correct your thermostat spacer issue, finish assembling the motor, go boating.

 

[Bondo]

Running on water hose connected to engine waterpump inlet at low rpm,

Ayuh,.... Welcome Aboard,.... To add to what Scott said,...

You should be feedin' the water into the t-stat houisin', at the hose from the outdrive, not to the circulatin' water pump,....