Winter Thermostat

[BenCT]

Hi, when I’m winterizing the cooling system with anti-freeze if I have this valve do I still have to take out the thermostat? I ran the coolant through the engine with the switch up and down.

Also, if I do take out the thermostat, after disconnecting the tubes and taking the bolts off, do I just use a flathead screwdriver pry off the top?

Thanks

[zellerj]

If you drained the block first with the pipe nipple behind the alternator, you should be good to go. If you did not drain the bock of water, then I would be suspect that the antifreeze is the correct potency to prevent freezing. You do not have to remove the thermostat to winterize the engine, but moving the valve open and close assures that no water is trapped in the valve.

[BenCT]

I ran fresh water to get the salt water out, I let it run all the fresh water out keeping an eye on temp and listen for the water to decrease from exhaust and then ran over 5 gallons (think 6 or 7 I over bought) of the pink stuff mixing the valve up and down (more of the time down as that is when it cools my engine so going through the block).

[zellerj]

I think you will be good with that much antifreeze going through the block. However if you want to save some money, if you drain the block using the pipe nipple behind the alternator, and then start the engine with the water pick up hose in a jug of pink antifreeze, you will see pink coming out the exhaust after about 1 gallon. Then I switch the water intake hose to the second gallon, and pour marvel mystery oil down the air intake of the carb to fog the engine and cause the engine to stall. I use the rest of the gallon to winterize the head. I don not have to winterize anything else on my boat.

[BenCT]

I was wondering about fogging the carb…thanks for that explanation. I am weighing fogging vs taking it off and cleaning and putting it in a bag. As I had some issues that may have been carb related at the end of the season I want to get to know my carbeurator a little better and taking it off seemed like a good weigh to do that.

[hanleyclifford]

By all means take it off and to your home. Clean in detail and get a rebuild kit from Moyer Marine. Before removing the main (brass) jet take the time to grind a screwdriver to be an exact fit in the slot. Do the same for other brass jets if needed. Take your time.

[BenCT]

So I decided to pull the thermostat to take a look at it. Looks like a new thermostat is long overdue. This explains why my engine would get too hot when the valve was open and I could only have a reasonable temp with the valve closed as the thermostat wasn’t working at all.

[BenCT]

Any thoughts on buying a Moyer marine thermostat vs just getting an off the shelf thermostat that is significantly cheaper? Also any ideas on how to make it easier to remove the thermostat in the future? I had to cut the tubes leading in and out. I guess will be easier with new tubes, but should be some way to make it easier if I’m going to do it annually for Winterization.

[hanleyclifford]

https://moyermarine.com/product/ther...e-csth_01_134/ If you are going to stick with the late thermostat arrangement this makes a lot of sense.

[msmith10]

If you reverse the water flow through the exhaust manifold by routing the hose from the thermostat cover to the far end of the manifold (closer to the reversing gear) then run the hosing from the forward end of the manifold out to the wet exhaust T, the extra length of hosing makes it easy to remove the thermostat cover without removing any hoses. This also helps keep the manifold a little cooler at the forward end.
And if it were my boat, I'd replace that thermostat cover as well as the thermostat.
The thermostat in your photo is not the expensive 2 stage thermostat. It can be replaced with an off-the shelf unit as long as the dimensions and opening temp work. Your cover has been modified (with a spacer) so you can use a cheaper one with a longer reach. Moyer used to sell those modified covers and cheaper thermostats but I don't see them on the site anymore. You have to enlarge the forward mounting hole to accommodate that elongated nut (maybe called a shoulder nut?)*but that's an easy job. Reuse the spacer.
Zellerj is right on with removing that drain plug. However, after snapping off that 6" nipple once (fortunately an easy remnant removal with an easy out) I do this with extreme caution.

[edwardc]

Originally Posted by BenCT

…any ideas on how to make it easier to remove the thermostat in the future? I had to cut the tubes leading in and out. I guess will be easier with new tubes, but should be some way to make it easier if I’m going to do it annually for Winterization.

A heat gun works wonders on old stiff hose.

[BenCT]

I’ve read a bunch of old posts and I realize that a lot of seasoned Afourians have run the engine without the thermostat for years. I like that idea a lot. It simplifies a lot of things. I think I’m just going to clean up the interior a little more, put on new hoses and omit a thermostat. I’ll paint the cover. I’ve run it without the thermostat functional all season with the bypass loop closed. Per getting hoses off I recall with my seacocks people use a product on the metal barb to remove the hose easily. I have to figure that out. I also read somewhere that the silicone hoses are easier to work with. I explored that and went with my old West Marine hose as I wasn’t sure which silicone brand to use and didnt want to take any risks.

Thanks for all the feedback.

[Dave Neptune]

Do not close off the bypass when running without a t'stat as the engine will run to cold. Install a valve so you can adjust the temp to around 130 ~ 140 at your higher cruising speed. The higher temp is better for running efficiency and oiling of the internals. The other nice thing is if she starts running hotter you can close the valve a bit more and continue on. This does two things. It tells you that something is going amiss in the cooling and allows you to get home safely to rectify .

I ran for 35 years without the t'stat and 4 times it informed me "SAFELY" that it was time for a vinegar soak. Never once overheated except when I lost my intake screen and sucked up something about 10 miles out. I blew the crap out with my fire extinguisher and continued on for a nice weekend at Catalina Isl.

Dave Neptune

[BenCT]

Sorry, meant using my valve to close out the bypass, this year I will try and use it halfway and play around with it. Last year with the valve in the closed position and now I know a most likely dysfunctional thermostat (I have not done the boil test) my engine temp would get to around 150/160 and stay there. But it would take a while. It would hover at 100 until I was in gear for 5 to 10 min. Keep in mind I have a brand new exhaust manifold, raw water pump and strainer so water was moving through pretty well. If I switched it to open the bypass valve my engine temp would sore up to 180 very quickly and I’d flip the switch to closed since I was scared something bad would happen.

[hanleyclifford]

Originally Posted by BenCT

I’ve read a bunch of old posts and I realize that a lot of seasoned Afourians have run the engine without the thermostat for years. I like that idea a lot. It simplifies a lot of things. I think I’m just going to clean up the interior a little more, put on new hoses and omit a thermostat. I’ll paint the cover. I’ve run it without the thermostat functional all season with the bypass loop closed. Per getting hoses off I recall with my seacocks people use a product on the metal barb to remove the hose easily. I have to figure that out. I also read somewhere that the silicone hoses are easier to work with. I explored that and went with my old West Marine hose as I wasn’t sure which silicone brand to use and didnt want to take any risks.

Thanks for all the feedback.

I was one of those who ran no thermostat for years but used a T valve bypass set up. It worked but I was always adjusting the thing and I finally succumbed to the Indigo remote unit. Since then the engine stays rock solid at 175.