Lou C
Supreme Mariner
- Joined
- Nov 10, 2002
- Messages
- 11,913
I'm posting this on the Merc board even though I have the OMC because I feel I'll get more responses and its a generic question.
OK I've had the OMC for a long time, and all their engines came with a 160 stat as did most Volvo engines, whereas Merc did use a 140 stat in their older applications. I have read and heard that for raw water cooling in salt water (which is all I do) you should have a 140 stat, because at higher temps the salt starts to drop out of suspension and causes deposits. Well when I took my engine apart, I didn't really see evidence of this, but wanted to try a 140 anyway. Sierra makes one for Volvo applications which fits the OMC perfectly because they used the same thermostat housing. In additon, even though its a Sierra, I think the same company makes them that makes them for BRP & Volvo because they have the same markings, same patent # etc.
So tested it in the pot of hot water, with my old school radiator thermometer. Sure enough opens at 140* and seemed to open more than 160* stats I have used. Now I installed it and idling on the water hose, all I am getting for temp at idle is 130*. With the 160* I got 155-165*. I have not launched the boat yet but my question: is this typical for a 140 stat idling on the water hose? I know for sure it opened and close to spec, tested it several times. What say you Merc folks?
OK I've had the OMC for a long time, and all their engines came with a 160 stat as did most Volvo engines, whereas Merc did use a 140 stat in their older applications. I have read and heard that for raw water cooling in salt water (which is all I do) you should have a 140 stat, because at higher temps the salt starts to drop out of suspension and causes deposits. Well when I took my engine apart, I didn't really see evidence of this, but wanted to try a 140 anyway. Sierra makes one for Volvo applications which fits the OMC perfectly because they used the same thermostat housing. In additon, even though its a Sierra, I think the same company makes them that makes them for BRP & Volvo because they have the same markings, same patent # etc.
So tested it in the pot of hot water, with my old school radiator thermometer. Sure enough opens at 140* and seemed to open more than 160* stats I have used. Now I installed it and idling on the water hose, all I am getting for temp at idle is 130*. With the 160* I got 155-165*. I have not launched the boat yet but my question: is this typical for a 140 stat idling on the water hose? I know for sure it opened and close to spec, tested it several times. What say you Merc folks?
