Yamaha 3GM30F intermittent starter

BCC Forum
1

Here’s a diesel question for Marty Chin or anyone who’s experienced & solved
this particular Yamaha 3GM30F problem.

  1. 90% of the time, I press the button, solenoid clicks in, starter turns
    over, engine starts.

  2. Last summer, after a nice sail north from Solomon’s on the first leg of
    our cruise to Maine I turned the key, hit the button, heard a faint click,
    nothing more, no start. This was after many months of no-problem starts,
    nary a problem with it. So we tucked into the Rhode River, anchored for the
    night and started investigating.

  3. Figuring that it might be a solenoid problem I shorted across the battery
    cable lugs on the starter and sure enough it turned right over and started.
    Let it run for a while to charge the batteries, turned it off, let it cool
    down a bit and then tried to start it again. Push button, click, but no
    start.

  4. The starter switch connections on the solenoid looked a bit oxidized so I
    cleaned & retightened them, hit the starter button and she started right up.
    Problem fixed? No.

  5. On the trip to Maine & back she usually started normally, but on a
    totally capricious schedule it had the same problem about one out of every
    ten starts or so. I can always get her running by shorting across the
    solenoid lugs, and after that she usually starts normally for at least a few
    times, then reverts to the same problem.

  6. If this was one of the “old load” $100 cars I used to drive many years
    ago I would just replace the solenoid. Cheap, easy, and if it turned out to
    be something else, not much time or money down the drain. But the 3GM30’s
    starter & solenoid seem to be an integrated unit, not friendly to
    disassembly and repair. I’m not sure what’s inside that Yamaha solenoid,
    but some of the old automotive ones had a copper disc inside that rotated a
    little bit everytime the Bendix engaged and thus presented a different and
    theoretically less-oxidized and pitted surface to the internal contact
    points. If a stout whack on the outside didn’t jar it enough to make a
    fresh contact, they were easy enough to take apart and clean. Or replace.

On the way back to the Chesapeake we stopped for fuel in Mamaroneck and the
diesel mechanic at the original Post Road Brewer Yard said something to the
effect of “Oh, a lot of those Yanmars have that problem, probably not a
tired solenoid, you just need a heavier gauge of wire from the starter
switch to the solenoid, that’ll fix it.”

So. Solenoid? Starter switch? Wire gauge? Gremlins?
What’s the most likely problem/solution to address before I just start
disconnecting inaccessible wires to check resistances, or replace the switch
& starter/solenoid assemblies. Anyone had this intermittent problem?
TIA,
Scott
(Itchen, BCC 73)

2

Hi Scott,

We have a pretty new 3GM30 which has this exact problem. It took us
a while to pinpoint what was happening as we also had a flat battery
a couple of times.

About one start in 8 or 10 - and entirely unpredictably - we just
get a click. Our solution is two-fold: switch straight to the glow
plugs for 40-60 seconds and then start and if all else fails open
the decompression levers. It always works. I haven’t even
investigated the solenoid. I’m afraid I can’t shed any light on the
cause.

Do you have any trouble with the “3GM30 Death Rattle”? Our engine -
and it is apparently well known to Yanmar that this happens - goes
into a death rattle if you rapidly come from a moderate or high rev
level to idle. You would think that the engine is going to shake
itself off its mounts. The Yanmar dealers reckon that they can
largely fix the problem so we’ll see.

Regards

Mike

3

Hi Scott

I had that same problem on my Nor’Sea 27. It turned out I had a bad ground.
I would increase the wire size and make sure the ground is more than
adequate. It is a wiring problem.
Fair winds
Bob

4

Scott:
Since you say that you do hear a “click” when it fails to work, the secondary contacts of the solenoid are suspect. I’d replace it. (Some solenoids have reversible contacts, you might check that.)
If you don’t hear a click, then start by jumping the?secondary input (battery terminal) of the solenoid to the primary input; if that works, then your problem is probably upstream of the solenoid to the switch, to the battery. The switch could be bad, the connections corroded (you said you checked that,) or the wires could be corroded inside the insulation. In the case that it isn’t a corroded connection, replace it all, switches and wires. It’s a little known fact that wires conduct current mostly on the outside of the wires; when the wire surfaces corrode, the resistance goes up noticeably.
Bob’s comments about a grounding problem are valid, also, and easy to check.
Failing that, you might be in for a new/rebuilt starter. If you’re a real do-it-yourselfer, and have the time, you might be able to rebuild it for the cost of parts, like brushes, bearings, etc. Start out by checking the wear on the brushes.
Pax.

5

Quoting Mike

Hi Scott,

We have a pretty new 3GM30 which has this exact problem. It took us
a while to pinpoint what was happening as we also had a flat battery
a couple of times.

About one start in 8 or 10 - and entirely unpredictably - we just
get a click. Our solution is two-fold: switch straight to the glow
plugs for 40-60 seconds and then start and if all else fails open
the decompression levers. It always works. I haven’t even
investigated the solenoid. I’m afraid I can’t shed any light on the
cause.

Well, when trying to start with low batteries and coooold November/December
temperatures the decompression levers have always saved the day for us. But
glow plugs? Unless I’m missing something my 3GM30 has none. Helped a friend
bring a Cabo Rico down the coast in the Fall a couple years ago and it’s
Universal had glow plugs – and that was very welcome when starting cold.

Do you have any trouble with the “3GM30 Death Rattle”? goes into a
death rattle if you rapidly come from a
moderate or high rev level to idle.
Regards

Mike

There’s a real racketey rattle for a few seconds when starting, but only
when it is cold and it smooths out right away. Never happens when throttling
down our Yanmar, as you describe.

Scott

6

Pax and Bob,
Thanks, I think the evidence points to an excessive resistance problem
between switch and solenoid contacts, since the starter itself works fine
once it gets enough current. The engine and wiring are all clean and well
maintained, but some of the switches and connections are fairly old. Guess I
will do some checking with my multimeter and see what turns up --there may
be more than one bad connection, all together adding up to insufficient
current at the solenoid’s electromagnet to pull the contacts together firmly
enough. Since it is unpredictably intermittent it would seem that the
switch, button or solenoid contacts are all prime suspects, maybe abetted by
not quite robust enough wiring. One other bit of evidence is that the
solenoid usually clicks – but sometime not (!). That would point to a
problem upstream of the solenoid magnet.

In any event, sooner or later before we go too far a-field I guess it would
make sense to pick up a new starter/solenoid unit and rebuild the old one to
keep as a spare. I don’t think that the solenoid can be replaced separately
but I’d be glad to find out that I’m mistaken in this.
Regards, Scott

7

Scott:
It still sounds like the secondary contacts are suspect. They always fail intermittently. You should be able to replace just the solenoid. A downloadable Yanmar manual is available at: Seloc Marine Repair Manual Online: Yanmar Diesel Inboards 1975-1998 For available parts, try googling “yanmar marine engine parts”.
Pax.

8

Yanmar “death rattle”
?
Not necessarily specific to Yanmar, I have seen this on a number of engines where improper idle speed and throttle cable adjustments caused a “death rattle” when returning from mid-upper RPM range. Problem occurs when the idle speed screw is set to low and the throttle cable is being used to set the idle speed-Improper procedure.
?
Using a digital tachometer and reflective tape on the crankshaft pulley, start and run your engine until warm, stop engine and disconnect the throttle cable. Take a reading using your digital tachometer, should be between 650-850 RPM, if not readjust.

Raise and lower your engine RPM by flipping the throttle arm on the engine, set it pop back naturally, do this several times to make sure the throttle lever is seating against the idle stop screw. Recheck your idle speed several times when the engine idle speed levels out.

If the idle speed is incorrect, readjust and repeat step 3 and recheck idle speed. Continue until idle speed remains within limits in step 1.
Move your shifter until the throttle lever is in the neutral if single lever/dual function lever or to the idle position.

Readjust your throttle cable at the engine, recheck idle speed after reattaching the throttle cable, if it stays constant you have a good fix.

Most Yanmar engines are supplied with a spring-loaded terminal which attaches to the end of the throttle cable and inturn attaches to the throttle arm on the engine. If used, insure the throttle cable terminal is adjusted so the spring pressure of the terminal is the only pressure used to push the throttle arm to the idle position. Allowing the cable to fully compress the terminal and forcibly push against the throttle arm will eventually damage the throttle arm and associated internal components.
?
Starter problem:
In addition to the information emailed to me off site, please check your battery voltage using an analog multi-meter, digital units react to slowly to be effective. With a fully charged battery 13V across the terminals.

1, Check your battery voltage at the battery terminal and record your results, should be 13V.
2. Check the battery voltage at the starter where the battery cable attaches. Should get 12.5-13V.
3. With the meter set on the Ohm setting check between your ground terminal on the battery and to the block near where the ground cable attaches to your engine, should be zero ohms. If not remove the cable and clean terminal lug and block where attached, recheck results, if still showing high ohms replace the cable. Yanmars have had a lot of grounding problems associated with paint coupled with corrosion and in some cases related to where the ground cable is attached to the engine.
4. Check your Yanmar manual and relocate the ground cable to the spot above and aft of the starter as specified in the manual.
5. Check Ohms between the bell housing and the base of the starter, should be zero ohms, if not remove the starter and clean the starter base and bell housing, do not grease or paint this surface. Wire brush and 3M scrubber pads work great.
6. Check voltage at the battery while someone else attempts to start your engine, If your battery voltage drops below 10.5 volts, replace your battery. If your voltage is 10.5 or higher see step 4
7. Check voltage at the starter as described in step 2 while some one else attempts to start your engine. Again should be above 10.5 volts, If step 5 stays above 10.5 volts and step 6 goes below 10.5 replace clean terminal and recheck, if clean already, replace the cable.

If all above checks ok:
Using a remote starter switch, remove the ignition wire from the starter solenoid, attach one lead of the remote starter to the solenoid ignition terminal and the other lead to the starter positive post. With the remote starter switch, attempt to rotate your engine sever times, if all goes well your starter is ok.

More often than not, the problem is in the control panel start button or ignition switch, these will have to be ohm checked with the DC power shut off. Should be zero ohms when testing these circuits.

Believe it or not Yanmar and most engine manufacturer control panels are not warrantied once you take possession, are not water proof! Unless a wire is cut in the harness or water has created corrosion in the terminals at the back of the panel or at the connector plug at the port aft rear of the engine, Yanmar harness seldom have any problems, larger wires/conductors are never needed.

To set up the idle properly, disconnect the throttle cable. Run and warm the engine to full operating temperature.

Good luck on your projects
Marty Chin, BCC Shamrock
Bay Marine Diesel

9

Thanks Marty, that’s all very useful including the off-list info on the
non-serviceability of the solenoid (that will save me some time). I think I
will start by checking the condition & resistance of the ignition key and
starter button since that’s the one area I have not yet opened up to have a
close look at and as you point out, it is pretty exposed to the weather. On
my list of “someday projects” is to make a protective cover or flap to ward
off rain and give that panel and the key some protection from accidental
impacts. I’ll check the other resistances also. The batteries are getting
along in years and though they still do pretty well, the cumulative effect
of low voltage and one or more marginal connections could be source of the
problem. However the failure to start seems as likely (or more so) when the
batteries are freshly charged as when they have been sitting so I’m voting
for it’s being a bad connection or the switch.

I think I will print out all your very detailed BCC & Yanmar maintenance
tips and bind them into a troubleshooting manual for the boat! Not to make
work for you or someone else, but wouldn’t it be nice to have them as part of
a FAQ for the BCC owner’s website?
Thanks again,
Scott

10

Scott -
?
A FAQ spot might be really interesting - I’ll see what kind of work that entails.
?
Cheers,
Nica