That is my concern, so I am biting the bullet and getting a new one from Westerbeke as they will stand behind it. The Z-400 is what I see as well, but I do not have a Kubota dealer nearby and do not want to hold up the yard's dock longer than needed, nor do I want to give them a tractor part that might have some silly little difference that stops the mechanic in his tracks. All of the input here has been terrific, however. I am still curious as to chicken or egg as cause, but will be sure there is good alignment when all is done. My sense is the odds say the belt broke first, being 25 years old, but we will never know I guess. Turns out my engine panel is a standard model with no low oil/overheat alarm built in. Been sailing now for 50 years and this is my first tow, so I cannot complain.
Blown exhaust not enough I guess
- Thread starter odaydokay
- Start date
More likely than not, the belt failed because the coolant pump was or had failed. The pumps fail for a number of reasons. Corrosion, bent shaft, too much tension in the belt are the three most common. I had mine go out when the boat was about 13-years old. That replacement pump has been working well for the past 23-years.
I got my pump from the local Kubota dealer, but they are also available from many suppliers on-line.
For the M12, it turns out the situation is tricky. There were apparently two different M12 cases, one where the impeller offset from extends from the pump flange 3/8", the other is 1/2" and they are not interchangeable. One has to remove the old one and measure because they do not even go by serial number of the motor! The 3/8" offset requires pump part no. 301336, the 1/2" gets 302756. Both then require the same gasket, 301340. Hansen Marine (NE Distributor) reports about once a year someone tries to "eyeball" the clearance and winds up putting in the wrong one and cracking the casting, so not something to fool with. Those of you with other Universal engines may have it easier.
This turned into 6 hours of shop labor as two of the 4 pump bolts sheared and also the Adjuster bolt on the alternator bracket. The tech's (an old guy who has seen a lot) opinion was that the pump seized shearing the belt not the reverse. Maybe the lesson is if your engine is 20+ years old, change out the fresh water (coolant) pump as you will get no warning such as a drip we see on the sea water pumps.
yesterday was the first test of the repaired pump. I ran the motor for several hours and was surprised and a bit disappointed that it ran around 200 degrees, which is just over the "north end" of the limit. The exhaust water was luke-warm, so I figured she is not going to blow. After cool down I took a look at the anti-freeze level and saw it could take a bit of a topper. It took only 3 ounces but on today's run the temp ran around 180 the whole time, the exhaust water was not really warm, so either 3 oz. makes a big difference in this engine or maybe there was a bit of an air lock that had to be worked out. In any case, I am breathing easier.
I'm guessing you had a little bit of an air lock that cleared itself, possibly when you added the few ounces. The exhaust water isn't a great indicator of the engine coolant temperature. The exhaust will only heat up as much as the heat transfer capability of the heat exchanger lets it. But it sounds like you're at a good running temperature now.
I have found that my M25XP is very sensitive to any loss of coolant. I installed a coolant overflow serge tank so that the system is always full. You can find them at most auto parts stores.
Universal Coolant Radiator Reservoir Bottle Overflow Tank New Dorman 603-001 | eBay
Universal Coolant Radiator Reservoir Bottle Overflow Tank New Dorman 603-001 | eBay
Many thanks to you both for checking in. Very useful thinking from both of you and much appreciate the time you both took!
The dinghy adds a little drag and the rough bottom adds a more significant amount, so those could be contributing to some temperature increase if you’re at the limit of what the heat exchanger can cool. The engine doesn’t really know whether it’s going upstream or downstream though; it just knows you’re going a certain speed through the water. So unless you’re increasing the RPMs to hold a constant speed over ground the current won’t make a difference.
That's sort of what I thought but there it is going up river running 15 degrees hotter, right at normal coming down and on the sound "going flat" Puzzling I guess as I did not increase rpm's, just accepted the lower speed.