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"Thelonious"

Ericson 38--Fuel Injectors Service

Rating: 1 votes, 5.00 average.
Small diesels are renowned for their simplicity. They have no ignition system and in a pinch they'll run on cooking oil. Diesel fuel doesn't aspire to be napalm, and unlike gasoline feels almost natural on the skin. Diesels work forever with minimal maintenance and seldom a complaint. What's not to like?

Well, they can be hard to start. It's mostly an issue in cold weather. The sea trial of Thelonious II was done on a foggy, 60-degree morning in the dead of Southern California winter. It took two applications of glow plug --maybe 30 seconds each--before the Universal 5432 four-cylinder engine kicked over, sputtered, and ran like a top. We put the delay in firing down to the extreme cold. Yes, in my world people begin to stamp their feet and blow into their hands when the temperature goes below 65.

The engine surveyor was Martin Ball of Long Beach, who found no issues after a two-hour inspection. I do routine engine maintenance myself-- changing oil and fuel filters and keeping tabs on raw water impeller, zincs, fresh water coolant, water heater and leaks, of which there shouldn't be any.

What else can I do, Martin?

"Well, you can have the fuel injectors checked out. The engine is 30 years old and probably nobody ever did."

That went on the to-do list at place #278 and never got above #200. Two summers later I was 100 miles offshore on the way to Oahu, and when I went to start the engine it took five tries cranking before it fired up. We were on a howling beam reach at the time, shrouded in spray and everything damp and cold. Hmmm. Only 5,000 miles to go.

As the passage progressed the engine became more and more reluctant to wake from its slumber, until on the final leg I was holding the glow plug button down until my finger fell asleep. The batteries were fine (diesels are high compression engines and do require a strong spin by the starter motor). To preserve fuel and keep the noise down in the cabin I had put on many 5-knot motoring hours at 1700 rpms, sometimes less. Normal cruise is 2300 rpm and 6.5+ knots. Was I lugging the engine? By chugging along was I encouraging carbon to build up? Does anybody have more question marks than a solo sailor with a numb glow-plug thumb?

Safely home again the engine was still slow to start. Two 30-second glows at least, sometimes more. Time to deal with the fuel injectors. The job turned out to be easy enough:

--Carefully clean the engine block with brushes and shop vac. We can't let crud fall into the exposed cylinders.
--Remove fuel blow-by hoses between injectors and the lines to injector pump and fuel tank.
--Remove as a unit the steel injector pipes connecting injector pump to injectors. Try not to bend them much.

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A 15/16th wrench may be required if the injector frees before the top nut does

--Remove the top injector nut and "double nippled fitting".
--Remove the fuel injectors. I used a Husky 1 1/16th" deep socket on a breaker bar. It just fit over the injector body. Kubota sells a special socket that permits removing the injector with "double nipple fitting" still attached. One forum member used a grinder to modify a deep socket so it would fit over his injectors. (All Kubota parts are metric, but the right metric wrench may be hard to find on a shelf.)

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Testing diesel fuel injectors requires specialized equipment which the local boatyard probably doesn't have. I drove mine to Becs Pacific in Whittier, an hour away. There are Internet diesel-injector-by-mail services that promise a rapid turnaround, and the postage may be cheaper than your driving time. Such services check the spray pattern and usually provide a printout and an estimate of repairs.

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The report from Becs was that the spray patterns of my 33-year-old injectors were fine. They suggested cleaning and changing the heads. Price: $50 each. In case a new injector is needed, advice comes in a chorus: don't buy from Universal/Westerbeke! Our diesels are based on Kubota tractor engines, and Kubota parts can be a quarter of the Westerbeke list price.

Here's a Universal-to-Kubota parts list: http://www.ericsonyachts.org/infoexc...ht=#post109778

I was advised to carefully bag and mark each injector so they could be reinstalled to the same cylinder. I did. Becs gave them back to me loose in a box. Oh well, it didn't seem to matter.

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At lower right, replaced injector head

Reinstalling the injectors is straightforward, but new injector hoses may not be so simple. For one thing, the Kubota hoses are very unlike anything on the shelf of a marine diesel shop, a specialty hose company, Autozone or anywhere else I could find. No choice but to order them by part number.

I was able to reuse most of my old injector hose, excepting the return fuel line from injectors to tank. Turns out that the fitting on the fuel tank is much larger than on the injectors, so a Kubota fuel line won't fit anyhow. I made do with stock 1/4-inch fuel line for the return line (its wall thickness is twice that of Kubota's). A passing mechanic said he runs into the issue of different sized fuel hose fittings all the time.

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After this job the diesel needs to be thoroughly bled. I used my usual trick of simply turning on the auxiliary electric fuel pump.

The engine started all right--with the sound of serial nuclear explosions punctuated by earthquakes. I concluded I should shut it down. The decision took 1.3 seconds. However, it was 10 minutes before I could breathe again.

Martin Ball answered my panicked telephone call on the third ring. "Ho Ho," said Martin in his unflappable Englishman way. "You still have some air in the system, don't you think?"

One thing I don't do while working on engines is think. I follow instructions. So, Martin, the instruction, please?

He said to use the starter to prime the injectors. An electric pump can't do it. The injector pump only works if the engine is turning over.

The next day, while my spouse cranked the engine (with the raw water intake turned off), I loosened all four fuel pipes at the injectors, and when fuel spurted out tightened them back down.

The engine started right up. No banging, no smoke, no fuss.

All there is to it, fellows.

Do the rebuilt injectors make for faster starting? Yes. One 20-second shot of glow plug is now all that's required for an instant start. Previously it had been up to four tries of 30 seconds each with 10 seconds of cranking in between.

I used to figure my Universal 5432 burned 3/4 gallons an hour. Still not a bad ballpark estimate.

However, my actual fuel burn at 1700 rpms for 142 Hobbs hours was .49 gallons an hour.

That's 700 miles of motoring without bunkering. It's why we have a diesel.

Here's Kubota on bleeding the injector lines: http://www.orangetractortalks.com/20...njector-lines/

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Updated 11-05-2017 at 01:07 PM by Christian Williams

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Maintenance and Mechanical

Comments

  1. Loren Beach's Avatar
    Have you ever replaced the glow plugs? I have not done that, but did have the injectors fitted with new tips about a decade ago.
    We preheat about 12 seconds most of the time. One winter I started up when the ambient was about 20 or 25 degrees F, and it took 30 seconds or a bit more.

    Simple engines, but that 'simple' list of parts is really important.
  2. Christian Williams's Avatar
    I did on the previous boat. Report here.

    I think if the voltmeter dives when the button is depressed they're probably operating OK.
  3. Kenneth K's Avatar
    Great write-up. Thanks. Injectors are about #278 on my list, too, which means I'll probably be needing this info a lot sooner than one would have guessed.
    Updated 10-10-2017 at 01:34 PM by Kenneth K
  4. supersailor's Avatar
    If the engine is running fine after startup (eg: no smoke, revs fine) the starting problem is probably in the glow plug circuit. The engine on Terra Nova needed a full minute at least of glow plugs to start then still started hard with belches of smoke. When I finally got disgusted with the factory system that had been grossly altered by P.O.'s, and ripped it all out and redesigned it all everything changed drastically. I put the glow plug circuit on a heavy duty relay so the heavy current path is under 3' from the battery to the glow plugs. The result was a dead of winter start at 28 degrees ambient after 10 seconds of glow plugs and no smoke, missing or other diesel antics. The original setup had the heavy current traveling over 30' with too light a gauge wire (original harness). It was also passed through the ignition switch which was at it's current limit. The voltage drop in the original circuit was to 9.1 volts. The drop on the new circuit is to 11 volts. The result is energizing. I also separated the start and glow plug circuits. The plugs aren't needed when the engine is warm and having to push both was irritating.

    Bob
  5. Christian Williams's Avatar
    Hmmm. Makes sense. I'll take a look at my wiring this weekend.