She runs!

Ms. Bettencourt's 1980-something marinized 3-cylinder Kubota power plant may not look like much, but when it has clean fuel without air it runs like a clock.

Such was the case this afternoon after I reassembled the fuel system and bled air from the on-engine fuel filter and the injection pump.

The last time this engine had been running was December 26, 2014. Despite having been sitting cold since that date, she turned over and started easily with only 15 seconds of glow plug help.








This close-up (below) presents an opportunity to point out a bit of marine engine historical trivia.

Take a look at the black label on the air intake tube. If you click the photo at right to enlarge the picture you may be able to read the legend:

Universal
Atomic Diesel

In spite of the label, this engine is beyond a doubt a 1985 or later Kubota D-1101 tractor motor. Kubota was using them in its L-245 DT tractor in the 1980s.

Universal was a very successful marine gasoline engine manufacturer that had sold about 40,000 of its Atomic-4 sailboat engines between 1947 and 1984. Then, suddenly, sailors and sailboat builders quit using gasoline engines. Small diesels had become more reliable and were much safer than gasoline engines in marine environments.

Universal needed a diesel product, so they bought a bunch of Kubota tractor motors, painted them gold and sold them as Universal Atomic Diesels. But, they didn't move fast enough. Universal lost market share to other engine firms and ultimately went out of business.

It is still possible to buy Universal labeled parts for these engines, but the smart money avoids the premium price on this stuff and buys most needed parts from the local Kubota dealer.

It is said that these engines, when well cared for, can go about 10,000 hours before needing a major overhaul. Ms. Bettencourt's engine has about 2,500 hours on it.

Newer marine diesels are lighter and quieter that this old piece of iron, but some would say they are more complicated and somewhat less reliable.

But, of course, all of this motor trivia begs the important questions: Have I or have I not found the elusive air leak in the old Kubota's fuel system?

Please stay tuned for test results to come.


UPDATE 1/14/15 Cold engine started easily and idled smoothly. Temps in the low 40sF.

UPDATE 1/16/15 Another easy start and smooth idle.

UPDATE 1/18/15 Started easily. Ran smoothly. Changed oil and oil filter. Declared victory. Awaiting arrival of Spring in full readiness condition.

Cold, cold, cold

Ms. Bettencourt is there, in the water on the other side of the gazebo, obscured by the fog. But I am not going down there. Too dank and chill.

So, what little boat work is being done is happening in the 70F shop, where I think I found the long elusive fuel system air leak (again).

I believe air could have been getting past the o-ring on the secondary fuel filter bleed valve. The take-out o-ring, shown in the clamp in the center of this photo, is the suspected culprit.

If you click the photo to enlarge, you will see the old o-ring is somewhat flattened and deformed, compared to a new o-ring shown in the foreground.

The bleed valve  is in the hex bolt on the top of the filter assembly, shown below on the bench, freshly painted and with a new o-ring installed.

The forecast is calling for warmer weather next week.

If that proves to be true, and if it doesn't rain, I'll go down the ramp to the boat and start putting Ms. Bettencourt's fuel system back together.

Assuming success with this repair, the next job on the list will be a routine oil and oil filter change.

At least I hope it's a routine oil change. Seemingly simple jobs have been having a tendency to turn into protracted dramas around here lately.

Diesel showers

A diesel engine won't run when air gets in its fuel system. I have been contending with the air problem in Ms. Bettencourt's 30-year-old Kubota 3-cylinder diesel for at least a couple of years. Every time I think I have the problem fixed, the fix has proven only temporary.

Only one thing appears to be sure about the air intrusion: It has to be happening some place between the tank and the fuel injection pump. So this time, I disassembled the whole system -- from tank to injection pump.


The first fault I found was not air related, but was a lucky discovery nevertheless. This bracket, bolted to the aft end of the engine, serves as a pivoting point for the throttle and shift cables, and as a mounting surface for the on-engine fuel filter. The filter body bolts into the two large holes in the foreground in this photo. A replaceable spin-on filter canister screws into the bottom of the filter body.

Anyway, if you click on the above photo it will enlarge and you should be able to see the pre-catastrophic crack in the rusty metal. This was a the lucky find. I will get this fixed and will clean up and paint the part before re-installing.

The next discovery was on the filter body itself (left). The mating surface between the filter body and the gasket on the spin-on filer canister was heavily corroded. I wire-brushed the mating surface corrosion, then polished the surface with steel wool. Once re-assembled with a new canister, this part of the puzzle should be air-tight.

And, while I have it all apart ...

... all the fuel lines and hose clamps will be replaced and I will do something about this strange fixture on the top end of the fuel withdrawal tube (shown here laying across the coil of fuel line hose).






Here's a closer look at this funny fitting. The pipe coming out of the solid-looking elbow has a substantially smaller inside diameter than the rest of the fuel system plumbing. It could be a fuel-flow choke point. It could be making the the suction side of the lift pump have to work harder. Perhaps this too could be a part of the air intrusion problem.

My plan is to cut this little tube off and bore, tap and thread this thing so it will accept a 5/16-inch barb fitting such as the barb shown in the assembly at the bottom of the photo above.

After that's done, I'll put the whole system back together and bleed the air out of everything.

That's when the diesel showers will happen. I have never failed to avoid liberal sprayings of bubbly diesel fuel when I bleed air from Ms. Bettencourt's fuel system.

After the bleeding, and probably before I clean my glasses and launder my shirt, I expect the old girl's power plant to start up easily.

Only time will tell if this will solve the air problem. Stay tuned to find out please.