Thermostat

[DKR]

I have an OMC Cobra Model 2.3 Litre engine and it overheated. I have put in a new water pump and was wondering if it continues to overheat if the next option is to check the thermostat? How will I know if the thermostat is bad? If I need to replace thermostat, is it a relative easy task? Once I take the bolts from the thermostat housing is it obvious what has gone bad?

 

[APPALOOSA2]

Re: Thermostat

Which water pump ? The one on the engine or the one in the outdrive ?

 

[DKR]

Re: Thermostat

Replaced the one in the sterndrive

 

[APPALOOSA2]

Re: Thermostat

Does it overheat with ear muffs on in the driveway ?
I would pull the thermostat and try it on the lake and if runs cool then I would put a new thermostat in. Don't run with out the theromstat all summer your engine will not get up to proper temp and suck more fuel and build up more carbon.

 

[DKR]

Re: Thermostat

Just put new water pump in today and have not checked it with muffs to see if it is overheating in driveway. I will do that tomorrow - if it is overheating still I assume the next step is replacing the thermostat? Is that a difficult project, replacing the thermostat?

 

[HT32BSX115]

Re: Thermostat

Just put new water pump in today and have not checked it with muffs to see if it is overheating in driveway. I will do that tomorrow - if it is overheating still I assume the next step is replacing the thermostat? Is that a difficult project, replacing the thermostat?

No.

It's not very hard at all. You need to test it though.

Just put it in a pan of water (on the stove) with a thermometer and measure the temp. Determine what temp it opens and if it opens all the way.

Thermostats fail.....but not often.

 

[APPALOOSA2]

Re: Thermostat

Just make sure you snug the thermostat housing tighten firmly ,don't put a lot of force on it or you will crack it.

 

[DKR]

Re: Thermostat

I took out the thermostat and tested it on the stove in boiling water, it opened when boiled and closed when I took it out of water. So if the overheating continues what would be the next issue to consider. I replaced the impeller initially before testing the thermostat.

 

[Bt Doctur]

Re: Thermostat

After checking for a normal amount of water flow, then suspect the manifold or riser being plugged up

 

[DKR]

Re: Thermostat

Do you have to take the manifold and/or riser completely apart to determine if it is plugged and if so which one do I tackle first?

 

[Bt Doctur]

Re: Thermostat

Riser is usually 4 bolts but it may be just 2, not that famliar with the omc`s.
manifold 6-8

 

[DKR]

Re: Thermostat

After putting in a new impeller and checking to see that the thermostat was opening and closing (boiling on stove, it was) I put it back in, took the boat to the lake and it would not start. I brought it back to the house put the muffs on in the driveway and the engine turns over easily. What could be the issue for not starting in the lake but starting easily in the driveway?

 

[DKR]

Re: Thermostat

How can you check to determine if there is a normal amount of water flow as you state?

 

[DKR]

Re: Thermostat

After putting in a new impeller and checking to see that the thermostat was opening and closing (boiling on stove, it was) I put it back in, took the boat to the lake and it would not start. I brought it back to the house put the muffs on in the driveway and the engine turns over easily. What could be the issue for not starting in the lake but starting easily in the driveway?