Need Some Help from the Diesel Gurus

[noelex 77]

The starter motor has 8v.
The glow plugs have an unknown voltage ( but he light dim when they are turned on)

Fix these problems first.

If the engine does not start when these known issues have been addressed then its appropriate to look for other causes such as low compression.

[GrowleyMonster]

Originally Posted by Charlie

* I held a board over the air intake covering up most of it. According to Nigel Caulder this get the engine to spin faster. Engine started.

BRILLIANT! I just learned a cool new trick!

[twistedtree]

I agree that you need to track down the 8V problem. Ignore all the rest until that's fixed.

You mention visually tracing the positive cables, but what about the negative? Follow the whole negative path from the battery back to the starter.

After a visual inspection, you will need to repeat the voltage drop test for various segments of the electrical path to locate the problem. Visually identifying a problem is great, but just because something looks good doesn't mean it is good.

I'd first measure the drop across the negative leads, then the positive. To measure positive, connect the post VOM lead to the starter, then the negative to the neg battery post. Get it on the post itself, not the cable clamp. Doing this you have cut the negative path out of the equation. If you see less voltage than the 8 or so you had before, then the difference is the drop through the negative path. Trace it on cable segment at a time until you find the problem.

My money is on a bag ground/negative connection. That would explain why house lights dim so much. BY the way, you have enough of a voltage drop that you can probably do all the tests just running the glow plugs, not the starter. It might make for easier testing.

[FlyingCloud1937]

Originally Posted by Ryan H

Well Gentlemen,

Its 5:00am for the fourth night in a row, its 17 degrees and I'm crawling around the motor some more. I'm going to try to be thorough to minimize how many more nights I've got to have like this. Wandering my way around several of the web sites provided I'm fairly sure the motor is in fact an M-12, though the pictures I've seen aren't 100% exactly like my motor, I did find an M-25 that is a carbon copy other than the fact that the M-25 has a third cylinder.

Mwahahaha, Making progress already and I didn't even have to get my hands too dirty on that one!

Rummaging through an online manual does show that what I originally thought might be my gear shifter really is the emergency shut off. Before I sound too much like the idiot my nearest and dearest know me to be the cable does run to the back of the cockpit and connects to a shifter. Weird huh? when the shifter is in 'neutral' the shut off is set to half on half off, when shifted to forward its on, and when shifted into reverse its off. I got the back of the boat opened up and found the back of the shifter is directly attached to the shut off via a swing linkage, and the actual shift cable is hanging off to the side doing nothing. For what its worth when I pull up on the real shift cable the motor tried to spin the prop while turning over, which I guess means I don't have a hydro-something or other tranny.

Now, back to the task at hand! I double checked the glow plugs, both showed 1.5 ohms resistance, not trusting it I pulled off each in turn and ground the thread to the engine block and they both heated up beautifully. Glow plugs thoroughly check. Next I opened up the fuel bleeder and ran the fuel pump. Diesel geysered out like it was old faithful, definitely no air in the injector pump. Next I pulled each injector line at the cylinder and ran the pump, wasn't Niagara falls, but squirts were definitely happening.

Several posts said the motor doesn't have a starting solenoid, I'm no mechanic, however theres definitely something next to the starter that looks pretty solenoid like. The positive side gets full voltage (with my buzz box hooked to the battery it was showing 14 volts). When the ignition is turned it sends between 6 and 9 volts to the starter. Thats checking with my multimeter positive lead on the bare wire running from the 'solenoid' to the starter and my negative lead on the block itself, no way I'm snaking both my hands around the belt to test both leads at the same time while on my tip toes leaning over the engine out through the companion way while turning the key with my teeth. That said, I was able to do most of that AND take pictures!

No worries, its a long story but reading it isn't nearly as painful as living it. Despite everything attempted, playing with what I guess I will now call the stop lever, glowing the plugs, covering the air intake, WD40 down the intake, blowing its hair with a hair drier, etc. etc. etc, it still seems to turn slowly, and the lights are still dimming even when I'm hooked up directly to a running car with a 90 amp alternator, two size 25 deep cycle 120 amp hour batteries, plus a starting battery with a cold crank rating of around 800 (not crawling back there again to check the number, but thereabouts). Finally my multimeter is reading next to no voltage drop or resistance at any cable along the whole electrical path.

WHEW!!!!!! Now I'll post some pictures. the 14 volt reading is the solenoid, the 8 volt is the starter which was actually fluctuating from 6 to 9 (I'm somewhat hoping that'll be the key to all this) got a geyser shot of the bleeder valve as well as the injector lines and finally a picture of my weird shifter line holder thats secretly a stop shifter....

Any ideas left?

What you have is a FCUK ie:FrenchConnectionUnitedKingdom

1. the pic #5 showing the throttle handle from the helm side appears to be missing the shift lever. Notice the center bolt.

2. the pic #6 showing the same but from the back side, demonstrates a break in the casting in he middle, and the lower half of said mechanism is free floating.



3. note the indentation in pic#6 above, that is the neutral lock out, so you can't put it in gear with the throttle racing.

4. at 14F not many batteries are going to be able to crank the starter, especial old bats with various of high resistance connections, no matter if you have a charger or jumper cables connected.

5. according to Mainsail's web if you have the Ford plug or 2, running to an amp meter, before it hit's the ignition key switch, then to the glow plugs...based on the condition of the vessel(pics tell the story), along with the lights dimming on energize of the glow circuit...then you have also a wiring circuit issue.

6. it's all good to have free fuel at the injector pump, when priming by hand. If ya don't have the same fuel at the injectors while ticikng over the starter, then a diesel engine will never start no matter what the temp is...glow plugs or not.

In the a post above the pick showing the black cable is the RUN/Stop Lever it should be connected to a choke style push/pull cable.

Lloyd

[noelex 77]

A man is rushed into the ER.
He has been impaled on a large metal bar that is still sticking out of his chest. His blood pressure is dropping and he is slipping into unconsciousness.

Dr Cruiser is called. He is a gifted surgeon. The best hands in the department, but some have questioned his diagnostic skills. A mild case of OCD has been blamed for his tendency to focus on obscure problems.

As the patient labours for breath, blood dripping from his mouth. The interns turn to surgeon for leadership. What should we do first, they cry.

Dr Cruiser quickly appraises the situation
"Lets do a prostate check" he announces.

Solving engine problems are a lot like diagnosing medical problems.

[HappyMdRSailor]

Originally Posted by GrowleyMonster

BRILLIANT! I just learned a cool new trick!

Growley....

Learned this trick so long ago, I don't remember who or when... It can be an absolute lifesaver, and or huge hassle saver... Use something that doesn't make a perfect seal, and that can be retrieved (wrestled from the suction) easily when she fires...

[DumnMad]

He turns the key and the lights dim. That would indicate high current draw-off through a parallel circuit(the starter circuit) i.e. High current going through the starter as it should or even a short circuit within the starter. Not a high resistance in the starter circuit blocking the current. If you try to start the car when you have your lights on the lights dim: - same thing.
I vote burnt out starter or jammed gearbox.

[noelex 77]

Originally Posted by DumnMad

He turns the key and the lights dim. That would indicate high current draw-off through a parallel circuit(the starter circuit) i.e. High current going through the starter as it should or even a short circuit within the starter. Not a high resistance in the starter circuit blocking the current. If you try to start the car when you have your lights on the lights dim: - same thing.
I vote burnt out starter or jammed gearbox.

The glow plugs must be jammed as well

Originally Posted by Ryan H

So here's the symptoms. When I hold the glow plug switch every light in the boat dims,

[forsailbyowner]

Originally Posted by Ryan H

Well I finally got my multimeter back. With jumpers running from my car to bank terminal no.1 I was getting 13.5 volts to both the solenoid and the starter. I bled the fuel lines at both the injection pump as well as the injector lines and found no air anywhere. Despite all this when I start the ignition lights still dim down and I get very slow cranking. Covering the intake doesn't seem to speed up the cranking at all. I did also check for an exhaust valve but haven't found one yet (pretty tight back there).

It seems like everything is starting to zero in on the starter being bad. I've popped the alternator and bracket out of the way so I can sort of get to it now although its proving to be a real pita to get a wrench or socket in there. Once the starter is out is it something an armchair tinkerer can test/rebuild or can I add this to the list of various kinds of professional help that I need?

I got my hands on a computer so I'm going to try posting some pictures again

Thanks everyone!

Yes an armchair tinkerer can definately rebuild a starter. I recently went through a somewhat long drawn out affair with mine. It took some sluething and ordering wrong parts before I figured out the correct bushing combination. There are multimeter tests for just about every component although a "growler" I guess is the definative test for the armature. You can still check for shorts and opens with a multimeter. Once you've been through it though it will be simple next time. Mine showed good or passed the bench test at the local auto place, but still spun waaay faster after new brushes, bushings and small parts kit.

[DumnMad]

Theres a lot of current going somewhere, the lights dim and the motor turns slowly. In a car this might happen if you try to start with the lights on and in top gear. So overheating starter, overheating glow plug circuitry, or turning prop???

[noelex 77]

Originally Posted by DumnMad

Theres a lot of current going somewhere, the lights dim and the motor turns slowly. In a car this might happen if you try to start with the lights on and in top gear. So overheating starter, overheating glow plug circuitry, or turning prop???

The symptoms of dimming lights can be produced by a short circuit ( or near short circuit), causing a "lot of current to go somewhere", or by excessive voltage drop.(for example a poor battery connection or flat battery will produce the same symptoms in a car)
It is impossible to tell from this single symptom of dimming lights which one of the two possibilities is occurring.

However the fact that these symptoms occur in two separate systems ( the glow plugs and starter) suggest that that is it a single problem shared by both of systems. This strongly implicates voltage drop.
Poor wiring shared by both systems
A poor contact shared by both systems
A poor start battery shared by both systems.

Since the battery and most of the wiring is shared by both the start system and the glow plugs a single failure here would produce both signs. This is more likely than separate faults in two different systems.

A jammed starter, gearbox etc would not produce dimming of the lights when the glow plugs were engaged.

It is obviously impossible to make a foolproof decision based on these limited signs. We need to interpret these signs correctly and identify the most likely cause that is consistent with the observations. This should be used as starting point for troubleshooting the problem, rather than an absolute diagnosis.

[CaptainDana]

Originally Posted by charliehows

couple of things - havent seen any mention of a compression test - apologies if i missed it, i mainly read the ops posts only. If the compression isnt up to scratch you can forget all the ancillaries. I'm assuming the engine has never run for the op.

A little parable based on personal experience - starter motor dragging, flat batt. suspected but tested fine, tried a wiggle of the main ht lead to starter mtr, felt solid. After quite a bit of swearing and other creativity i for some reason went to remove the main ht lead to starter - it was very loose but had sort of welded itself to the stud so to a superficial wiggle it felt solid - #%^&!!!!. Tightened it up and the starter took off like a rocket.

look on the bright side - if you ever get this thing running you'll know every inch of it.

Holy moly! I just got done diagnosing this exact problem. If the starter isn't running fast enough, the compression will not occur fast enough and there won't be enough heat to start the engine with or without glow plugs active.

Another clue is the voltage drop ( lights dimming etc). A good battery will stay well above 11volts WHILE CRANKING a healthy starter.

Assuming all voltage drops total to less than 0.7 volts (battery+ to starter B and starter ground to battery-), there are two things that will cause slow cranking and dimming lights: a bad starter or a sulfated battery.

The OP has probably fixed the problem by now but, he might have had both problems. He may have started with a sulphated battery whereby he ruined his starter with all af that cranking.

I highly recommend Diesel Basics and Diesel II classes.

[casual]

tp://www.pbase.com/mainecruising/universal_wiring_harness_upgrade

[daddle]

Note that many small engine starters are "generic". That Kubota starter may well be identical to say some small Nissan or Toyota starters. In other words, cheap to replace.

But I think the problem is elsewhere.

[sanibel sailor]

Does anyone else find it frustrating trying to figure out a engine start problem by laying clean hands on a keyboard?