Hot Water heater

[crieders]

My domestic hot water is not hot ! Yet the engine runs fine at 175 degree approx and all else seems fine.  I know there was a thread on this a while ago. Any suggestions? Thanks. Cliff c34 tall rig, 1022, 1990

[tonywright]

This probably means that you are getting no flow of coolant from the engine through the heater.

There are a couple of potential causes that I can think of:

1) No flow from the thermostat connection. Could be caused by an air lock in the system, or even low cooolant. if an airlock, try opening the bleed valve on the thermostat with the engine running. Some have posted here on ways to "burp" the system to get good flow.

2) Blocked hoses. This could depend in what you are using for coolant. Stu Jackson recently wrote up a project to replace his hoses, and recommends all with boats over 10 years to inspect their hoses. His were in really bad shape, which became obvious when he opened up the floor to check.  Search for Stu's posting on this, it was within the last month, I think.  (See Stu's link below)

Tony

[Stu Jackson]

Here's what Tony was referring to:  http://c34.org/bbs/index.php?topic=3769.0

[Ron Hill]

cliff : Your engine is running a little hot at 175.  It should run at 160 degrees. 
If you needed to "burp" the coolant to the water heater your engine would be running well above 200+.

You didn't mention how long you've been running the engine!!
So' I'll guess that you've got an open thermostat if you only have short engine runs of 1 hr or less OR you have an obstruction in the hoses to the water heater (like Stu mentioned) for longer engine runs.   

[Stu Jackson]

Cliff, Ron's post reminded me of another thread I started on hot water heaters, in addition to the one Tony mentioned.  Try this one, too: http://c34.org/bbs/index.php?topic=3133.0

[crieders]

Thanks for the threads. I usually don't motor much; that is true. I did put new hoses in over the winter but I had the same problem last season. Sooo maybe its time for thermostat replacement. Any advice on how to do that?

[Ken Juul]

When you put the new hoses on did you pour the antifreeze mixture in one one hose until it came out the other?  If that circuit isn't full it won't heat the hot water tank.  A thermostat that is stuck partially open will cause the engine to run hot as well as a dirty heat exhanger.  Think you need to check things item by item until you find the cause and it might be multiple items.

[Ron Hill]

cliff : I assume that you have a M25XP engine???  If you have go to your Kubota dealer and get a 59C (160F) thermostate.  Also get a new gasket. 
Look up the part numbers from the D950 Kubota engine parts list on our web site.   

[Stu Jackson]

Cliff, changing the thermostat is the easiest thing to do on your engine.  The parts can be found from reply #6 on this thread:  http://c34.org/bbs/index.php?topic=3133.0   I ordered them from the Livermore dealer.  You can use any source you want, just avoid over paying for a Universal part, like Ron says, it's a tractor engine.

The thermostat is staring you right in the face when you open the engine compartment.  Two bolts, lift up the housing, take out the old T stat, remove the old gasket, slap a new gasket on, set the new 'stat in the hole, and replace the bolts. 

A picture of the engine identifying the parts can be found at http://www.marinedieseldirect.com/universal/200157/universal-owners-manual-m25-specifications.html

[crieders]

thanks for all the help. I ran the engine for about 1-1 1/2 hrs with the cap off for  a little while and that seemed to do the trick.