Roger Long wrote:
"Martin Baxter" wrote

When I installed it I went over it with a infrared thermometer and
found very little variation in temp from the bottom of the block to
top of the head, may about 5deg C after 10 minutes of idling.


Hmmm. Nearly even temp after 10 minutes. Maybe that's why 5 minutes is
such a common recommended warm up interval for diesel engines of this
class, close enough to evenly warm but not running excessively at no load.

Indeed, but Volvo says nothing about not running for extended periods at
idle. They do seem to almost brag about how much charging current one
gets from thier souped up alternator at idle.

Cheers
Marty

On Mar 25, 12:56 pm, "Roger Long" wrote:
Refresh my memory or check this. Is the hunting only at full RPM?

Typically when it is acting up it can hold ~1000 pretty steady even
with a load but looses power above that if any load is applied and
starts hunting. The cycle always starts with a loss of rpm and may
drop all the way off to slow idle and then a slow recovery. As things
warm up the dips become smaller and smaller. I know what it sounds
like but... I am thinking of taking Wayne's suggestion of getting a
bit of 1/4" clear hose and putting it between the filter and the
injection pump just to confirm my strong belief that the system is air
tight. And at some point I suppose I will drop $25 on the diesel
group. Working the throttle back and forth and lubing the axle did
free things up noticeably. It will be interesting to see if it is
better in the morning.

Cheers,

-- Tom.

On 2008-03-25 20:09:32 -0400, " said:

On Mar 25, 12:56 pm, "Roger Long" wrote:
Refresh my memory or check this. Is the hunting only at full RPM?

Typically when it is acting up it can hold ~1000 pretty steady even
with a load but looses power above that if any load is applied and
starts hunting. The cycle always starts with a loss of rpm and may
drop all the way off to slow idle and then a slow recovery. As things
warm up the dips become smaller and smaller. I know what it sounds
like but...

With this restatement, I'm thinking along the lines of a restriction.
Remember that Roger stopped needing the electronic pump when he
replaced the rubber hoses.

Is it possible that the hose is kinked or has something resting on or
against it that could restrict flow? Is it old enough that the interior
of the hose could be swelling up?

You might be able to swap hoses to see if the problem switches engines.
I'd blow out the lines to clear any foreign material while I was at it.

--
Jere Lull
Tanzer 28 #4 out of Tolchester, MD
Xan's pages: http://web.mac.com/jerelull/iWeb/Xan/
Our BVI trips & tips: http://homepage.mac.com/jerelull/BVI/

On Mar 25, 3:41 pm, Jere Lull wrote:
Is it possible that the hose is kinked or has something resting on or
against it that could restrict flow? Is it old enough that the interior
of the hose could be swelling up? ...

Well, its all still fairly new, but I'll go over it again. There
certainly aren't any obvious kinks and the hoses look like new from
outside. The total length of hose from tank to injection pump is less
than 10 feet. I can't see bothering to swap hoses but it wouldn't be
a big deal or a big expense to replace them. Good thoughts. Thanks.

-- Tom.

Roger Long wrote:
"Marty" wrote

Indeed, but Volvo says nothing about not running for extended periods at
idle. They do seem to almost brag about how much charging current one
gets from thier souped up alternator at idle.

Could be marketing or it could be that the engine was designed and set up to
be more tolerant of idling than most small marine diesels which were
developed before electrical loads on small craft were anything like what is
common today.

The latter makes sense, the design is quite new and the advertising
specifically mentions todays higher electrical loads. The motor's
emissions meet or exceed EU and California Standards. I only installed
it last fall, put maybe 4 hrs on it before winter lay-up. It does beat
the tar out of the old single cylinder Yanmar, smoother, quieter, more
powerful, yet I think easier on fuel.


Cheers
Marty

"Roger Long" wrote in news:47ea2372$0$1113
:

A fuel restriction problem should only show up above a
certain RPM.

Noone has addressed my post about an AIRLEAK on the suction side of the
primary fuel pump.....bubbles will drive it crazy.

On Mar 26, 7:42 am, Larry wrote:
"Roger Long" wrote in news:47ea2372$0$1113
:

A fuel restriction problem should only show up above a
certain RPM.

Noone has addressed my post about an AIRLEAK on the suction side of the
primary fuel pump.....bubbles will drive it crazy.

The tank is gravity feed. The fuel pump was fine when last
disassembled and inspected and the problem pre-dates that, but in any
case it isn't required. I could run the fuel line directly from the
tank to the engine's fuel filter... Would that mean anything?

I got a new and worrying symptom today. Yesterday when I was feeling
around in the inspection port one of the cranks fell away with a
"plink". Of course, I'm very aware that the only way to get in there
properly is to remove the gear case and so I was not thrilled by that
development. However, moving the throttle crank back and forth did
bring the missing crank back up to the injection limiter and I figured
ok, maybe the weights just fell back or something. So, with some
trepidation, I turned the beast on and it worked perfectly. Cool.
Now, I just ran it again after letting it sit for the night and it
worked wonderfully for about 15 minutes. I was able to load up the
alternator with a bunch of stuff hooked to the inverter and some fans
etc and had perfect throttle control and was getting ~100 amps out of
the thing in either fast idle or in gear and pushing against the dock
lines... Smoke free and purring smoothly. Then, it started its
hunting again and when I removed all the loads and let it sit a while
it didn't get any better. Hmmmm... What is going on? It has never,
ever done the hunting thing after it has started running correctly
before.

-- Tom.

On Mar 26, 12:20 am, "Roger Long" wrote:
... Even though you have a gravity day tank, the
mechanical pump on the engine could be having an effect on fuel flow.

Hmmm. I'm sitting here listening to the engine run now. It seems ok
and is putting out ~40 amps. But, I'm thinking you may be onto
something. Could it be that the fuel pump is occasionally jamming
with the diaphragm compressed? It would be odd as I have had the
thing apart and all the bits worked nicely and it didn't seem to have
an effect... Still. Anyway, off to put some more load on the thing.

Cheers,

-- Tom.

On Mar 26, 9:04 am, " wrote:
Anyway, off to put some more load on the thing.

And, it's working fine... It is running with about 80 amps of load on
it right now at about 2100 rpm and looks, smells and sounds sweet...
Not, that I'm ungrateful for that, but I sure am confused...

-- Tom.

On Mar 26, 9:53 am, "Roger Long" wrote:
If it continues to run right, I'll be ready to pronounce that the tweaking
and exercising of the governer parts worked out what little left over
manufacturing burr or flake of rust had gotten in and jammed something.

Thanks. I keep hoping it will cure itself. I'm not convinced it has
done that though as the order of events goes:

Fiddled - tested ok
left to sit overnight - tested ok for a bit and then failed still
hunting when shut down
left to sit a bit - tested ok did not hunt on start-up...

I'm stumped. And I've kind of given up on the injection limiter per
se. I'm not convinced yet that it isn't some intermittent failure of
the governor but it is a puzzle...

-- Tom.