I have a 50 HP 4JH engine which is suffering about a 30-40% loss of
power. I cleaned the fuel, changed the Racor and the engine filter,
and cleaned the fuel injectors. THe engine will run up to 3500 RPM in
neutral but in forward or reverse only about to 1500 RPM, thus I am
only getting about 25 or 30 HP, if that.

A new high pressure fuel injection pump costs about $1500 or I could
have it rebuilt for about $800. One thing is that the manual
lever-operated fuel transfer pump which hangs off the side of the high
pressure pump does not work. I installed an electric fuel transfer
pump. The final fuel filter is a non-Yanmar filter. I am going to
bypass it just to see if I am getting a high presure drop across it
when I need a higher flow rate.

One other possibility is that the transmission is bad. I got salt
water in it twice via the external salt water oil cooler, but there is
no way to check it that I know of. I installed a clear plastic tube
on the return line from the cooler so I can see what color the fluid
is. (Salt water turns the oil the color of Pepto Bismal - pink and it
froths).

I am on my boat on a remote Colombian island called Isla San Andres,
about 200 miles north of Colon, Panama. Parts are imposible to get
here. I am considering sailing the boat to Colon where I can get any
parts I need. It might be a good idea to rebuild the transmission
first to see if that is the problem. My son is looking into a rebuild
kit and service manual for a Borg-Warner velvet drive transmission
model number 1017014. He can send it to me in Panama. Everything that
is sent to this island goes through customs in Bogota and is held up
for 2 to 3 months, thus the reason to sail the boat to Panama. It is a
down hill two-day run there with a good following sea and a beam reach
all the way, so I will not need all 50 HP.

I have traded some e-mails with the Yanamr service tech at Mstry
Engione Center in St. Pete, FL but not much help (basically sent it
back for a rebuild is the response).

Any help would be appreciated.

Jerry Poore
S/V Pelleas
Isla San Andres, Colombia

Jerry,

I do not know if this may help but there may be a filter on the electric
fuel pump. Mine is a small cylinder on the end of the fuel pump cylinder.

Also I wonder why you would get full revolutions when in neutral and not
when in gear if the transmission is bad.

Sorry I can't help further.

Good Luck

Ansley Sawyer
SV Pacem

On 25 Jun 2004 08:16:00 -0700, (Jerry Poore) wrote:

I have a 50 HP 4JH engine which is suffering about a 30-40% loss of
power. I cleaned the fuel, changed the Racor and the engine filter,
and cleaned the fuel injectors. THe engine will run up to 3500 RPM in
neutral but in forward or reverse only about to 1500 RPM, thus I am
only getting about 25 or 30 HP, if that.

A new high pressure fuel injection pump costs about $1500 or I could
have it rebuilt for about $800. One thing is that the manual
lever-operated fuel transfer pump which hangs off the side of the high
pressure pump does not work. I installed an electric fuel transfer
pump. The final fuel filter is a non-Yanmar filter. I am going to
bypass it just to see if I am getting a high presure drop across it
when I need a higher flow rate.

One other possibility is that the transmission is bad. I got salt
water in it twice via the external salt water oil cooler, but there is
no way to check it that I know of. I installed a clear plastic tube
on the return line from the cooler so I can see what color the fluid
is. (Salt water turns the oil the color of Pepto Bismal - pink and it
froths).

I am on my boat on a remote Colombian island called Isla San Andres,
about 200 miles north of Colon, Panama. Parts are imposible to get
here. I am considering sailing the boat to Colon where I can get any
parts I need. It might be a good idea to rebuild the transmission
first to see if that is the problem. My son is looking into a rebuild
kit and service manual for a Borg-Warner velvet drive transmission
model number 1017014. He can send it to me in Panama. Everything that
is sent to this island goes through customs in Bogota and is held up
for 2 to 3 months, thus the reason to sail the boat to Panama. It is a
down hill two-day run there with a good following sea and a beam reach
all the way, so I will not need all 50 HP.

I have traded some e-mails with the Yanamr service tech at Mstry
Engione Center in St. Pete, FL but not much help (basically sent it
back for a rebuild is the response).

Any help would be appreciated.

Jerry Poore
S/V Pelleas
Isla San Andres, Colombia
Jerry -

Since you have internet access, check he

http://forums.torresen.com/sailing/

Torresen is the Yanmar distributor in the northeast US. They are
worth 2 of Mastrys, but Yanmar in their wisdom makes me buy from
Mastry. The forum at the link above is excellent.

I'm no expert, but if the engine is failing to reach rpm due to load
issues like a foul prop or a binding tranny, I'd expect to see black
smoke at full throttle. If not, I think it is more likely that you
have a fuel system problem. My 3GM30 behaved like yours when my
electric lift pump bit the dust, FWIW.
__________________________________________________ __________
Glen "Wiley" Wilson usenet1 SPAMNIX at worldwidewiley dot com
To reply, lose the capitals and do the obvious.

Take a look at cpRepeater, my NMEA data integrator, repeater, and
logger at http://www.worldwidewiley.com/

The following letter appeared in Latitude 38's June edition. You may find
it very helpful:


THE ENGINE PROBLEM IS FINALLY SOLVED


We finally have a happy ending to the trials with our injector pump
which, you may remember, caused us to be late to the start of last year's
Ha-Ha. Readers might find it interesting in that it demonstrates how
complicated it can be to solve some engine problems.


The Problem: In normal conditions our 88-hp Yanmar diesel would power up
to 3,400 rpm under the load of our 20-inch Max Prop on our Tayana 52. But
we experienced a problem with the diesel auxiliary not powering over
2,000 rpm under the same load. The max output without load is 4,200 rpm.


The First Occurrence: We had no problem motorsailing into heavy weather
coming down from Anacortes, Washington, to San Francisco at 2200 to 2800
rpm - with 3,400 rpm on demand when we crossed breaking bars. On the
delivery from San Francisco to Newport Beach, we ran at 2,600 rpm until
Point Conception, at which time we slowed to 2,000 rpm for six hours.
When we tried to speed up again, the diesel would not go over 2,000 rpm,
even under full throttle. And the turbo would not spool up.


The Diagnostic Decision Tree: We quickly ran through our simple skills
without results. Through the efforts of a series of professional diesel
mechanics, we created the following diagnostic flow for debugging this
problem. Some of this was so simple, yet creative, it was worth taking
notes.


Suspected Problem - Restricted Fuel.


Step #1 - Visual inspection to see that there was plenty of fuel in both
tanks.


Step #2 - Visual inspection to see that the fuel filters didn't have air
or contamination.


Step #3 - Replace filters. Still no change in power.


Step #4 - Run engine off one gallon day tank connected to hose from the
top of the secondary filter. Still no change in power.


Step #5 - Replace secondary filter again. Still no change in power.


New Suspected Problem - Overpitched Prop.


Step #1 - Replace Max Prop with fixed 3-bladed prop that was originally
shipped with boat. No change in power.


New Suspected Problem - Restricted Air Flow


Step #1 - Remove exhaust pipe from engine and run under load. Still no
change in power.


Step #2 - Visually inspect turbine vanes by removing air breather.
Turbine spooled freely. Still no change in power.


New Suspected Problem - Lift Pump Failure


Step #1 - Hook up fuel straight to the injector pump by bypassing all
filters and lift pumps, and using a small electrical pump. Still no
change in power.


New Suspected Problem - Bad Injector Pump


Step #1 - Remove pump and bench test at specialty shop. Tested to specs.


Step #2 - Reinstall injector pump. Still no change in power.


New Suspected Problem - Bad Vacuum to Governor


Step #1 - Visual inspection. Hose all right.


Step #2 - Blow into hose. No air leaks. Still no change in power.


New Suspected Problem - Bad Injectors


Step #1 - Remove and POP test at mechanic. Tested all right. Still no
change in power.


New Suspected Problem - Bad Compression


Step #1 - Test each cylinder while injectors removed. Tested all right @
380 PSI.


New Suspected Problem - Bad Injector Pump


Step #1 - Remove and replace with new pump from Yanmar. Engine ran at
2,500 rpm and turbo spooled up. But still cannot achieve full power under
load.


New Suspected Problem - Overpitched Prop


Step #1 - Remove fixed 3-bladed prop and replace with Max Prop. Full
power at 3,200 rpm. Finally!


The lessons we learned:


1) At each step, the mechanic thought he had the problem solved. The
injector pump "never fails," and it tested OK. A mechanic did say
sometimes they test OK but don't work under real load conditions - which
are apparently hard to replicate on the bench. In any case, that was our
problem. We exhausted every other avenue before buying another injector
pump because it cost $1,600 - plus airfreight. We also had to wait for a
second replacement pump because the first one arrived with a hard
failure.


2) I always thought that boats that don't make the Ha-Ha or start late
were guilty of not trying hard enough. Well, we airfreighted two injector
pumps, and the first replacement one was bad. We drove to FedEx to pick
it up. We airfreighted the fixed 3-bladed prop to try it in place of the
Max Prop. We had two divers replace it while Beach Music was tied to the
Balboa YC, as there wasn't time to have the boat hauled. We used four
different mechanics to repair the engine because we had to move to San
Diego before the problem was fixed in order to make the start. After all
this effort and expense, we still had to start two days late - but we did
catch the fleet at Turtle Bay in time to make the beach party. In the
future, I will have new-found respect for other boats with technical
problems - rather than assuming they didn't try hard enough to make the
start.


3) Perseverance, time and money ultimately brings results.


Having been in Mexico for the season, we agree that cruisers down here
are obsessed with the weather. Even those who were groomed by the strong
winds on San Francisco Bay seem pretty timid.


We've been enjoying Profligate's reports from the Caribbean.


Kirby & Pam Coryell
Beach Music, Tayana 52
Northern California / Mexico