m 35-B thermostat

[tommyt]

We are experiencing some over heating issues and beleive we have a bad thermostat as the problem is inconsistent. I beleive the Universal is a Kubota but in my search cannot find the Kubota model #. Wanting to get a part quickly a tractor supply will be faster in our area.
Thanks for any help.

[KWKloeber]

The Kubota parts manual for the sister engine to the 35B is on the tech wiki -- see "manuals"

Early "B" and sister Kb engines used a 38 mm diameter thermostat, later the thermostat housing was enlarged and takes a 44 mm thermostat.

[Stu Jackson]

Yup:  http://c34.org/bbs/index.php/topic,3133.msg20069.html#msg20069

[tommyt]

OK, with the help of this site wegot the Kubota thermostat and gasket to mate with our engine. That was with 0 help from the local Kubota dealer.

Nowm the manual says that the gasket should be sealed, but it does not say with what! ?The Kubota guy says they don't seal theirs. So, having no faith in him, I ask the board for help again. What should we seal it with?

[Ron Hill]

Tom : I'd just make sure that both metal surfaces are clean, insert the new thermostat, put on the new gasket and evenly tighten the bolts holding the thermostat housing together.

If you have a leak, then I'd use some #2 non hardening Permitex on the surfaces., but first I'd try to seal it together without sealant.

A thought

[KWKloeber]

0 help from the local Kubota dealer.

manual says that the gasket should be sealed, but it does not say with what!

Tom,

Did you go to the dealer w/ the Kubota part numbers?
Which manual are you referring re: "should be sealed"

It helps to be specific and complete as possible so we can help you.

ken

[tommyt]

The Universal M-35B manual says to use swealant on the thermostat gasket.

[KWKloeber]

The Universal M-35B manual says to use swealant on the thermostat gasket.

WHICH?  the Service Manual?

Give us a hint where to look

[tommyt]

yes, the service manual,

[KWKloeber]

yes, the service manual,

Tom

Ok, so

the manual says that the gasket should be sealed, but it does not say with what!

Then I am confused then, the SM states:

Apply a liquid gasket (Three Bond 1215 or equivalent)
only at the thermostat cover side of the gasket.

If you look on Amazon and elsewhere, 3 Bond is there. A web search will also identify substitutes.

I'm also confused about the thermostat -- the Kubota part numbers are there on the Wiki in the Kubota parts manual, and from Stu's link to the old forum post, we just need to use the engine date to determine which thermostat fits.  We can order the part online without any dealer info or help at all.  Messicks.com is a great US based source for Kb parts.

Unfortunately, not all Kb dealers are the same but JTSO, we can't really blame them.  We don't have Kubota engines with Kb serial numbers or model numbers, we have Universal engines.  They deal with Kb equipment model numbers and Kb tractor part numbers.  Sure some go out of their way or are more knowledgeable (maybe have dealt with marine parts before?)  But if we expect them to "know" Universal models and their parts, would be akin to trailering a SeaRay to a Caddy dealer -- and asking for parts for a Crusader engine. Ya, they're both GM and might share a short block, but.....


all JTSO
kk

[Stu Jackson]

Before the advent of the internet, all I was "armed with" was 11 years of Mainsheet magazines, many tech articles discussed "How to Change a Thermostat."  Mine came with paper gaskets.  One cleaned both surfaces "religiously," put the paper gasket in, and tightened the bolts.  A later thermostat came with a ridged (NOT "rigid") gasket.  I tossed it and made my own gasket from a paper supermarket bag.  Same, essentially identical, engines.  Not rockets.  C'mon skippers...   

[Scott Hibbs]

To head off any confusion, Tom (who started this thread) is the PO.  He thought it was time to stop sailing, and I purchased the boat.  Tom joined me on the initial spring "assembly" and shake-down sail, and we found a lot in common - including wives that only tolerate sailing.  So, Tom has the best of both worlds...sold the boat, and continues to sail her!  Splitting dock fees, and other expenses, makes it a win-win both ways.

Now to the issue.  Thermostat replaced.  An easy job, even the bleeding.  But, the replacement thermostat has a higher operating temperature (180) than the thermostat removed (160).  Purchased a 160-degree thermostat from CD, and was ready to swap it out, until I did a fair amount of reading on diesel engines.  I recognize we are dealing with a marine diesel.  However, the Operator's Manual for the Universal M-35B that came with the boat (1st Edition, dated January 2000) specs an operating temperature range of 170-190.  Rev 2 of the Operator's Manual (dated February 2010), which is posted on our site, lists the operating temperature range at 150-170.

Sailnet had a good thread on normal operating temperatures, with the consensus being 180 as a better temperature for complete combustion resulting in improved engine performance.  Feed to the heat exchanger is fresh water (Lake Michigan), so no concerns on salt deposits at higher temperatures as some may see with a sea water feed.

Reading is helpful, but nothing beats experience.  Leave the 180, or replace with the 160?

[KWKloeber]

 Scott,

Diesels enjoy the higher temperature. 180 is better for you since you are on a GREAT lake.
I'm unsure however what the rating is on the high temperature alarm switch.   When I asked a couple years ago my distributor thought it was 205 or 210 so you should be fine.

Salt, use 160.