ZR6 Over Heating

[KONAKING]

Yes there is colant in the motor its dexcool and it looks fine. Well there was coolant in the motor I pulled the heat exchanger out again. I am also going to change the ECT. The T stat is new as of last year

[KONAKING]

Also there is temp sending unit and an ECT does the ECT go to the computer and the temp sending unit go to the gauge ? If so I dont think they would both be bad. So my thoughts on a bad sending unit dont hold water.
Someone also mentioned restricted exhaust flow. How do I check that without pulling the risers off?

[AirTool]

Also there is temp sending unit and an ECT does the ECT go to the computer and the temp sending unit go to the gauge ? If so I dont think they would both be bad. So my thoughts on a bad sending unit dont hold water.
Someone also mentioned restricted exhaust flow. How do I check that without pulling the risers off?

One goes to the ECM and one to the boat system for the gauge. Which is which I cannot remember. The parts diagram on line shows them.

[KONAKING]

Today I went thru the system again fresh and raw. I had plenty of water running through the exhaust I pulled the also pulled the plugs on the e manifold and had good water flow. I had good water flow coming out the exhaust from the back also. I did not have the chance to get it on the water though. I checked the water pump and t stat. If it still runs hot I will to admit defeat.

[teamseal]

Dont give up yet! If you have a Sears and Robucks close, go into their tool section and get a hand held infrared temp unit with the lazer pointer they are less than $45.00. Take it back and start your motor and start looking for hot spots or areas in the system that are particular to heat build up or surfaces near the ECT.

Looks like their are a few others that are suggesting changing out the ECT also, It is cheap enough.If nothing else ohm it out and see if it falls into its range, I know that is what I would do. The one that I had problems with I could not get a connection to the Diacom at the access port. this boat was a salt water boat and the connections had degraded to the point of non comunication. went around the system with the temp unit and could not find any thing wrong temp wise luckly we had another 6 liter in the shop and pulled the ECT from it and put in the problem motor Ta-Da ! fixed the problem.

[KONAKING]

Great Idea thanks I will try it. I still have a hard time believing that both my ECT and my gauge sending unit are both bad.

[KONAKING]

bump

[KONAKING]

Ok here we go again. Took the boat out skiing tonight after going through the entire cooling system again. This time I left the t stat out. I also had infrared thermometer with me. The boat gauge never made it above 140/150 and the was about what the infrared thermo showed also. This was t stat and I verified it open in hot water at 160 deg. It was refreshing not to see the temp climb into the 200's. So i will try a new t stat and see how it goes but atleast I have a problem and can work from there.

Thanks for the help great site and my next boat will be a SV-211 soon I hope.