volvo 2002 - heavy black soot - stop lever produces throtte responce

This motor is a 1986 volvo 2002 in a Elite 32.

Problem description

To start the motor I can repeatable follow this procedure

The throttle must be placed in the 1/3 advanced position and the stop lever lifted 3 times.

The starter is engaged and the engine proceeds start runing up to rough idle aprox 800 rpm. While belching out black soot upon the water and black smoke into the air

The problem is the throttle can be advanced with to the 2/3 position and beyond no change in RPM
one pull on the stop cable will allow the engine RPM to climb to 2500 RPM.

The throttle can now be fully advanced and 3300 rpm achieved. Prodigious amounts of black and blue white smoke now fill the air – a real attention getter

The throttle can be reduced in a fairly liniar fashion bact to 1000 rpm. If advanced again RPMs will not climb until the stop cable is once again pulled.

The water has a nice oil sheen at the end of this activity.


History

The problem began after the head was removed to repair an injector sleeve which was rising out of its seat. The head was sent out to be remanufactured this time. The boat was on the hard and not load tested after this repair.

The injector pumps were not removed no intentional change to any timing settings made.

So Far

After launching and observing this problem the intake and exhaust were checked for blockages, all fuel filers replaced, the lift pump cleaned, both injectors and fuel return line replaced, the valve adjustment was rechecked, and the throttle regulation box opened and all rods checked for free movement.

A compression test was done which showed only 270 lb compression in both cylinders. Mystery oild was allowed to soak in the cyl to free up possibly stuck ring with no positive effect.

There did not appear to be excessive pressure in the crankcase, or fuel in the oil.

Repair Shop Diagnosis

The only explanation put forward was the rings are bad .

Due to the age of the motor it should be replaced.


This has become a real head banding mystery to me.

It does a not make sense that bad rings would not cause crankcase pressure but only produce incomplete combustion products to exit through the exhaust.

I also cannot understand the relationship between the stop cable activation and RPM increase.


Does anyone have any insights into what could be causing either of these conditions and how to solve it ?

Does anyone have a good replacement motor to sell ?

Does anyone know of anyone who does ?


Thanks for reading my tale of woe.

JL

Sounds like it is dumping fuel.

Chris,

Thanks for the fast reply.

I would tend to agree that it is not the rings causing this situation.

What could be cause the fuel dump ?

During a head replacement is there anything which could be touched which throws off the injector pump timing ?

This model has two injector pumps could one injector pump not functioning correctly effect the other as both cyl appear to be contributing to this problem.

Do you know of any test to help narrow down the offending component(s) ?

JL

I am not familiar with this engine and I cannot direct you.

History

The problem began after the head was removed to repair an injector sleeve which was rising out of its seat. The head was sent out to be remanufactured this time. The boat was on the hard and not load tested after this repair.

The injector pumps were not removed no intentional change to any timing settings made.

If the engine ran fine before this repair was done, then something was not reassembled correctly.

so far I found one assembely error - adjusting the stop cable have given me full trottle responce - the motor runs steady up to 3600 rm in neutral and 2500 in gear - more that enough to obtain hull speed.

it is still dumping fuel - I'm changing the oil after each hour minutes of operation as there appears to be some fuel entering the oil -

has anyone heard of a lift pump getting out of time ? or causing a over fueling problem ? -- could it "drag" on the cam shaft causing the govenor weights to not deploy operate properly ?

it is a the only thing I can find as a common part - as each injector is fed by its own injector pump