Sweetpea 266ltd

1995 266ltd with carbd. 7.4 L Bravo One. 3rd season with zero problems thus far. Brought it home from storage a few weeks ago and de-winterized it. Did everything I was supposed to. When I ran it with the muffs (motor flushers) on it started up and ran fine...oil fresh and pressure A-o.k.; but, the temperature gauge never moved after running it a good 10-15 minutes. So, I brought it back home this weekend and put a new thermostat in it with new upper gasket (the one already in there was only 1 year old)...ran it again same thing! Next, found out that my lower gasket needed to be replaced it was worn...also, my lower gasket that is the bigger one that sits on the housing has 2 small metal rivets on each side of it. My brother explained that these act as a ground for the sensors to the temp. gauge - the marine confirmed this. My brother pulled of the sensors and ran a test on the gauge and with the ignition on it went all the way up thus working properly!! However, just put everything back together yesterday including new thermostat, new upper and lower gaskets and even clened and sanded the slightly rusty metal where the lower gasket contacts the housing especially where the metal rivets contact it. Ran it again for 10-15 minutes...gauge may have moved a hair but never came up. After turning off the engine I turned the ignition to the on position about 5 minutes later and it indicated a temp of about 170 degrees...is this a misreading? I have a 160 degree thermostat. Finally, I do have the flushing muffs that are dual so it gets plenty of fresh cold hose water to both sides of water intakes. Also, confirmed that water was flowing out of my prop exhaust and out of both of my Corsa tips through the transom...I could actually stick my hand under the exhaust water and it was warm but not hot. Could it just not be getting warm due to the very cold hose water??? I don't wat to run it at the lake if the gauge isn't working so I don't overheat it!! Please help, planning my first trip Sunday of Memorial Day weekend!!! Is there a problem or is it just not heating up??

88Fount33

I would run the engine again as you did for 10-15 min. then switch off for 5 minutes. Then turn on the switch to see if it does indicate that the temp goes to 170F, then go ahead and start the engine again at this moment at the same time turning the water back on to see if the engine temp stays at the 160-170 reading, if it drops below 160-170 then the new thermostat is either stuck open or there is another problem. I once lived in the frozen north and it sometimes took my engine a long time to warm up with 50 degree well water.

Sweetpea 266ltd

PROBLEM SOLVED! Went by the local marine yesterday and we pulled the proper thermostat parts and assembly up. It was a do-it-yourselfer mistake...I feel like a DA! Anyway my operations/maintanence manual did not actually tell how to put together the thermostat. The proper way is to install the small round cut out gasket, thermostat, then metal sleeve with opening towards front of boat (it can only go that way because it has a notch it fits into) up into the thermostat cover. Next put the larger gasket with the small metal rivets in it on the housing and carefully put the cover on and bolt it down. Man it all made sense once I did it. The thermostat actually sit up in the cover...I had it sitting to low down in the housing! Well, the good news is now I understand exactly how it goes together and I learned something. I don't think I hurt anything since I had water pumping and water flow...I will run it again next week and hope for the best!